Huberman Lab - Improving Male Sexual Health, Function & Fertility | Dr. Michael Eisenberg

Starting point is 00:00:00 Welcome to the Huberman Lab podcast, where we discuss science and science-based tools for everyday life. I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. My guest today is Dr. Michael Eisenberg. Dr. Michael Eisenberg is a medical doctor specializing in urology and an expert in male sexual function and fertility. He is both a clinician who sees patients, as well as a research scientist, having published over 300 peer-reviewed articles on male sexual function, urology, and fertility. And he is considered one of the world's foremost experts in male sexual health. Today we discuss a broad range of topics important to all men, including erectile dysfunction and function. We also discuss prostate health and

Starting point is 00:00:48 urinary health. We discuss fertility and sperm count. We discuss even topics seemingly esoteric, such as why penile lengths are actually increasing over time while sperm count seem to be decreasing. Today you'll also learn some very interesting surprises, such as the fact that a very, very small percentage of erectile dysfunction actually stems from hormone dysfunction. Rather, the vast majority of erectile dysfunction stems from issues that are either vascular, that is related to blood flow or neural.

Starting point is 00:01:19 And today you'll learn about a large variety of treatments for erectile dysfunction. Dr. Eisenberg also dispels a lot of common myths that you hear out there, both on the internet and in popular culture, that relate to male sexual health and function. By the end of today's episode, I assure you that you will have a thorough understanding

Starting point is 00:01:37 of what male sexual health is, how it relates to other aspects of health, and how to think about treating, maintaining, and improving all aspects of male sexual health, fertility, and function. Before we begin, I'd like to emphasize that this podcast is separate from my teaching and research roles at Stanford.

Starting point is 00:01:54 It is, however, part of my desire and effort to bring zero cost to consumer information about science and science-related tools, to the general public. In keeping with that theme, I'd like to thank the sponsors of today's podcast. And now for my discussion with Dr. Michael Eisenberg. Dr. Eisenberg, welcome. Thank you. Good to be here. I've been looking forward to talking to you for a long time because these days we hear a lot about the diminishing quality of sperm, which in some way seems to be tacked to the conversation

Starting point is 00:02:24 about diminishing quality of environment, people, intelligent, you know, there's a lot woven into this statement that sperm quality is declining. And some of it, I think people assume is related to environmental changes. Some of it, I think people assume it are related to changes in behaviors. So maybe less exercise, less sunlight. Who knows? Hopefully you'll tell us what's really going on. But the first question I have is, is sperm quality actually declining?

Starting point is 00:02:59 and regardless, what is sperm quality? Yeah, great question. So I think it's very controversial, I think, as your question alludes to. So I think we'll start by just talking about what sperm quality is and why it's important. So for reproduction, as you've covered on the podcast before, a man makes semen, and that has sperm in it. And so when we're talking clinically about a semen analysis, there's a few things we look at. We look at the amount of ejaculate semen that comes out. We look at the sperm, how many there are.

Starting point is 00:03:28 We look at their motility or movement. We look at their morphons or shape. There's some more advanced testing that's done in rare cases looking at fragmentation of DNA, for example, or there's some newer tests looking at epigenetic profiles of sperm. But essentially, these are all markers or fertility. So fertility in itself is a team sport, right? So it's hard to label a man as fertile or not fertile without knowing about his partner. But nevertheless, based on these different parameters, we try and quantify how. how likely a man is to be able to achieve a pregnancy.

Starting point is 00:04:01 So the World Health Organization every decade or so looks over the existing literature and defines these different cut points of what's normal or what's subfertile for those levels. So that's sort of the backdrop of what semen is and how these tests are done or what these tests represent. Now the question of whether they've declined over time has been a question for a number of years.

Starting point is 00:04:24 There was a landmark paper in the early 90s by Carlson and a group, and Denmark that showed this temporal decline over the last 50 years from that time point. And so what the investigators had done is looked over the literature for studies that reported semen quality around the world and noted that, you know, the quality in the earliest studies, like in kind of the mid-20th century, were here, and then over time they had sort of declined, the more recent studies. Now, that study was very controversial.

Starting point is 00:04:54 There was questions about waiting from different studies, because you can imagine imagine there's not a lot of early studies, so putting a lot more importance on those rather than some of the later ones. And so since then, there's been many other studies that have come out in time. And even today, it remains very controversial. I think, you know, if I were to say that I believe there's a decline, some of my colleagues and friends would be very upset with me. If I say, I don't believe it, some of my colleagues and friends would be very upset with me. So I would say that, you know, my opinion really varies based on whose paper I've read. And there's some very convincing, you know, studies on each side of it. You know, they're most recently just in the last year

Starting point is 00:05:35 or so, there was a met analysis of, you know, tens of thousands of men where they looked at, again, a host of these studies over the last number of decades all around the globe. So prior studies who really just focused on the Western Hemisphere, Western countries, because there was more data from that. But more recently, we've gotten a lot of data from Africa, from Asian countries, as well. And those also support this decline. So, you know, one of the counter arguments to why we're seeing that is just sort of an evolution of techniques over time. So that's one of the, sort of the popular questions about whether there's really a true decline. You know, I think as you're alluding to why there would be a client is also, you know, unknown. But you've sort of

Starting point is 00:06:21 labeled, you know, perfectly that kind of most common hypothesis. So whether there's some environmental exposures, right? A lot of things have changed over the last 50 years. And I think, you know, chemical exposure is certainly one of those. And there have been some fairly convincing, you know, preclinical studies. So, you know, mostly done in animals that show that like exposure to different chemicals, thallates, um, or BPA, other things may actually harm, you know, reproductive function for men and for women as well. And so it may be that, you know, these chemicals, you know, that are, that we're being exposed to as kids and adults or even probably more sinisterly when we're, you know, kind of developing in utero.

Starting point is 00:07:03 That may be kind of the most harmful exposure. But there's also been, you know, an obesity epidemic as well. And there's a strong link between a man's reproductive function and body weight. And so that's also thought to play a role in some of this, too. So I think there are convincing studies. But the other, I guess, aspect to this is that there's variations in semen quality around the country and around the world. There's geographic variation. And so that's also sort of an unknown explanation.

Starting point is 00:07:35 You know, there could be different sort of genetic, you know, compositions of men. And so there's different reproductive potential in that source. There could be different environmental exposures, diet, exercise, lifestyle. And there's a famous study done. a number of years ago where they looked at semen quality among fathers. So these are men that achieved a pregnancy. And at the first, you know, prenatal visit, they had the fathers give a semen sample. And so this was then four centers around the country. I think it, one in California, there was one in the Midwest. There was one in New York. So they basically found that semen quality

Starting point is 00:08:13 was sort of highest in the urban centers. In New York tended to be the highest numbers where it was, you know, lower in the Midwest. And so the hypothesis was potentially because it was a more rural setting, maybe there was pesticide exposure and that had led to these lower numbers. But, you know, another equally plausible explanation may be that, you know, different, sort of a different population. And maybe, you know, that could explain these differences. So I think it's, it's, you know, very important. And I think, you know, one of the sort of lacking things in this is there's not really longitudinal data. One of the greatest things would be if we just started tracking semen quality around the country, just like we do obesity, like, you know, Anne Haynes, a CDC's survey of health

Starting point is 00:08:52 in the U.S. if we added semen quality onto that. That way you could really see, you know, how it varies around the country and, you know, sort of compare like to like to see over time if there's really this progression. You know, one of the only studies to do that in Denmark that have started around, you know, around 2000 and tracked semen quality among, you know, volunteers that came in when they were conscripted for military service in Denmark, they were offered the opportunity to participate in this study. And so some men did. And what they found is actually that semen quality was fairly uniform over about 20 years where they had data. But sort of another very interesting part of that study is that only about a quarter of those men had normal semen quality.

Starting point is 00:09:34 So it was sort of very concerning. You know, it was I guess reassuring that it wasn't further declining, but very concerning that only a quarter of Danish men had, you know, normal semen quality. And they're one of the, I think, thought leaders in this field just because sort of a reproductive crisis there. You mentioned that some of this apparent decline in semen quality might be related to the fact that the tools to measure semen quality are getting better and better. And that would make sense if, for instance, one is just looking at total volume, morphology, which means shape, I should have clarified that, how many forwardly motile sperm there are,

Starting point is 00:10:09 and then also adding in, you know, a very sense. measure such as DNA fragmentation. Essentially, as the instruments get finer and finer, you discover more and more details. And if you are rating quality along a number of different dimensions, then it would make sense that those would tear out into different levels. So if one were to simply ask four couples who want to get pregnant and assuming that egg quality is not the issue, what percentage of failures to achieve successful pregnancy are the consequence of deficient sperm, deficient in any way. And is that number increasing over time? Yeah. So I think that's really key. I think when couples think about fertility, usually it's thought of as a female problem. And I think there's just historic reasons for that.

Starting point is 00:11:03 You know, if you look at data in the U.S., when couples do seek care for fertility, the man has bypassed probably a third of the time, even though when you look at the reasons for infertility, man contributes probably half of the time to infertility. So I think there's a half, half, yeah. So I think there's a huge need just to understand and evaluate the man. And one of the reasons for this, I think, is that, you know, one of the main treatments for infertility in the U.S. is IVF, which is very powerful. I think one of the greatest marvels of medicine in probably the last, you know, quarter century is our ability to mix a sperm and egg and dish and create a of life. It's really remarkable. But because it now takes just a single sperm, you know,

Starting point is 00:11:44 through something called inter-isidoplasmic sperm injection where you can inject one egg or one sperm into an egg, you know, the bar has gone down dramatically. You know, for couples just trying without, you know, any assistance, probably need 20 to 40 million moving sperm. But now with, you know, these remarkable techniques, you just need one sperm. And so because of that, you know, I think a lot of our innovation and research on male fertility has probably gone to the wayside. just because clinically, you know, we just need, you know, a few dozen sperm for most couples. What about testosterone levels? Are those also declining? We hear this. And when I look at the literature, I can find evidence for that. But the question is also whether or not the amount

Starting point is 00:12:28 of decline in testosterone levels is significant in a way that impacts, let's say, fertility, but also vitality in other ways, energy, mood, sexual health, et cetera. What's the story with testosterone levels? Are they indeed declining on average across the male population in the U.S. and elsewhere? I think there is pretty convincing evidence that that is happening. And I think the reason for that, again, is probably not certain. But, you know, there have been, you know, some pretty nicely designed cohort studies where they recruited, you know, men in the 2000s, the 90s, the 80s.

Starting point is 00:13:03 And you can see that depending on when these men are recruited, just matching age for age, these testosterone levels tend to be lower. And then N-Hains, which is, again, this sort of longitudinal study run by the CDC, that has also shown looking at testosterone levels over, you know, decades, that testosterone levels have declined over time. So there, you know, chemical exposure is one possible explanation. Again, either in adult or adolescent life or in utero. But obesity, I think, is also sort of a convincing explanation,

Starting point is 00:13:33 It's we're more sedentary, you know, we get bigger. That's one of the places that testosterone can decline. I think there's different sort of explanations for that. You know, as testosterone is produced, it's aromatized in peripheral tissue, you know, and fatty tissue, fat has a lot of this aromatase. So that converts testosterone to estrogen. So it necessarily, you know, lowers the testosterone level that's circulating in our body. Also just insulating the testicles or thighs get bigger, insulating the testes can also

Starting point is 00:14:01 sometimes lower the efficiency of production a little bit too. Because of heat effects. Because of heat effects. Yeah. I was going to ask about this later, but I'll ask about now since we're talking about my heat effects and sperm and testosterone, the heat of course being not good for sperm health and testosterone, which is I've read a meta-analysis. I don't know how high quality it is, but that explained that there is some evidence that there is some

Starting point is 00:14:31 evidence for either heat effects or possibly non-heat-related effects of cell phone, you know, smartphone in the pocket, impairing sperm health, maybe even testosterone levels. Now, you hear this more often in kind of biohacky, I don't know, circles, which, you know, I'm not a fan of the word biohacking. It's not clear what it means, but it sounds like it means something about taking a shortcut using one thing for a purpose it wasn't intended. But, you know, it also makes sense to me that a smartphone could generate some heat, some radiation that might impair testicular function and therefore impair sperm quality and or testosterone levels. But is there any real solid data

Starting point is 00:15:21 that carrying your cell phone in your pocket, let's assume on, that the cell phone is on, is bad for sperm health or testosterone levels? Yeah. So, I think there's not convincing evidence that it's going to help testosterone levels. I think that, you know, it's going to hurt testosterone? It's not going to hurt, yeah. So I should, you know, make clear that I think that in terms of production and heat effects, you know, sperm production is much more sensitive than testosterone production. But there have been some studies looking at cell phone exposure because, again, you're getting this,

Starting point is 00:15:52 whether it's heat, whether it's sort of the, you know, radio frequency, you know, waves coming in. I think you could posit sort of different explanations of why that may be harmful. So there have been some studies that, you know, looked early on, you know, men that used cell phones more or less, they had lower semen quality if they used it more. But you can also imagine there's huge differences in men that do and do not use cell phones. So, you know, it's a hard experiment to design. But there have been some studies doing this in vitro. So in the laboratories, so taking, you know, sperm in a cup, basically, and putting a cell phone next to it or not next to it to try and see if that played a role. There have been studies done where they sort of normalized.

Starting point is 00:16:31 the heat, you know, they kind of put on sort of a special stage so that it's not heat necessarily, but maybe it's RF exposure. So those studies, I think, don't show sort of a clinically meaningful change. But there have been some studies that say that maybe DNA fragmentation of sperm can go up a little bit if there's close proximity to a cell phone. So I think, you know, when patients ask me that, which is a common question I get in clinic, obviously, patients are coming in and they want to do, you know, whatever they can to try and improve their chances. So I think generally, I think the data is not convincing. But, you know, if it's easy enough, certainly to be aware of it, you know, I think putting a laptop on a desk rather than in your

Starting point is 00:17:10 lap, I think for heat exposure is probably the biggest thing that we want to minimize. About a year and a half ago, I did an episode about testosterone and estrogen where it's manufactured in the male and female body, et cetera. And I found a very interesting graph in a textbook on behavioral endocrinology by a guy named Randy Nelson, who I happen to know through. the field of behavioral endocrinology as it's typically studied in animals. So most of that book centers on animal studies, but there's a fraction of the studies that center on human data. And there was a very interesting graph that showed testosterone levels as a function of age in males. And as one might expect, testosterone levels were on average much higher in late teens, early 20s, 30s. And there

Starting point is 00:17:55 was a progressive decline. But what was remarkable to me about that graph is that even when exploring the scatter plots, because they showed individual points, they didn't just show the averages of testosterone levels in men in their 50s, 60s, 70s, 80s, even 90s, there were these outliers, these guys who had testosterone levels that were on par with testosterone levels of men in their 30s, but these guys were in their 50s, 60s, 70s, 80s, even 90s. So do you observe this clinically? Do you observe that men are coming in, you know, who are older than 40 and have testosterone levels and presumably free testosterone levels as well that are still very high?

Starting point is 00:18:40 You know, the reason I ask is that I think we've all been told and we presume that testosterone levels decline with age and one would expect some outliers. And of course, we don't know whether or not those guys in their 90s who have the testosterone levels of that matched the averages of men in their 30s didn't have even greater testosterone levels in their 30s. But given that they were sealinged out around 900 nanograms per decilator, you know, toward the high-end normal, depending on the scale, already at age 90, it's kind of hard to imagine that earlier they were walking around with, you know, 2,000 nanogram per deciliter testosterone. So do you see this? Are there some, is there just a lot of natural variation in

Starting point is 00:19:16 testosterone levels of men who walked into the clinic at any age? And of course, what is special about these individuals that are, you know, maintaining high normal testosterone levels into their later years? Yeah, that's a great question. I think this is such a common question. Anytime we talk about testosterone, I think anytime we talk about most sort of clinical tests that we do, you know, what is average, what is normal. So we do see great variation.

Starting point is 00:19:42 I mean, I think just like you're saying, I usually let everybody know that, you know, usually testosterone peaks, you know, kind of early 20s, and it tends to go down probably. probably 1% a year forever. But there are people that have very, you know, very, very high levels. You know, just mirroring, you know, that graph that you describe, I certainly have patients. You know, we screen four testosterone levels, you know, when patients come in with complaints where we're worried about that, low energy level, you know, low libido, some of the symptoms of low testosterone, sexual dysfunction. And, you know, to my surprise, sometimes these men, you know, I've seen 80-year-olds that certainly have the highest testosterone level I'll see, you know, for six

Starting point is 00:20:18 months. You know, why that is, I think, is not certain. Maybe it has to do with, you know, everything, with everything, there's probably sort of a bell-shaped curve and everybody's a little bit different. But androgen sensitivity, you know, sensitivity of the receptor, you know, they make it more efficiently. But I have not really noticed, again, because at least in clinical practice, you know, when patients come in, they come in with a complaint. And so even men, you know, with very high levels, they may have some of the same dysfunction men with low levels. So I think with low levels, you can try and treat that, and that may be the solution. But for men with, you know, these what we would consider high levels, you know, there may be other issues going on.

Starting point is 00:20:56 Let me frame the question I was going to ask a little bit differently. When someone comes in to your clinic and you measure their testosterone levels, as you mentioned, they're likely coming in because they have some issue, prostate issue, sexual function issue, et cetera. But you do get a read on their, you know, sort of crude measurements. morphology of their body, right? So you could visibly determine whether or not they're likely to be obese or not, regardless of age. So earlier you mentioned obesity as a risk factor for lowering testosterone and sperm quality. You mentioned that fat aromatizes testosterone into estrogen, so that's at least one mechanism by which that could happen. But if you were to just step back and

Starting point is 00:21:38 say, okay, if somebody who walks into my clinic tends to be, let's say healthier looking, you know, not obese, let's just put the cut off at what you would presume is obese. Is there a higher probability that their testosterone levels are going to be within normal range? Conversely, when somebody walks in and they're obese, do you fully expect their testosterone levels to be subnormal? Or are you sometimes seeing obese people walking in with high testosterone? And the reason I'm asking this is not to create confusion is that I think that everybody out there who's thinking about sperm quality and testosterone levels and this apparent decline, trying to figure out, you know, okay, what can we do in order to maintain the health metrics that are going to, of course,

Starting point is 00:22:26 increase fertility, but for those that don't want to have kids or already have kids, are going to at least maintain or improve vitality, is obesity really the thing to avoid? So is there a not one for one, but is there a tight correlation between obesity and testosterone levels? I would say that you cannot predict. I think that sort of would be the take home. And so I think that, you know, more information is always better. You know, when I see patients in clinic, you know, some patients are walking around, you know, with, yeah, everything is totally normal and they're very healthy. All the numbers come in at the normal range. But sometimes when men, you know, look totally normal, they talked about taking care of their life. They exercise, you know, five, seven days a week. Their testosterone levels can be very low. So even despite, you know, having what we would consider should really give them, you know, you know, symptoms. They're able to compensate. Maybe they've lived their whole life in that they don't know what normal is. Now we get them to sort of normal levels. A lot of times they feel better again because they had no idea how they should feel. But I think that that's just sort of important that everybody, you know, should be screened. I think that, you know, testosterone,

Starting point is 00:23:31 semen quality, there have been shown to even be barometers of health. So, you know, men with lower testosterone levels of higher risk of, you know, heart disease, diabetes, mortality. the same studies exist for semen quality as well. And, you know, again, they may have sort of a similar relationship and explanation why that may be. But I think it's hard to just predict, you know, based on appearance, what, you know, testosterone will be, what semen quality be, what testicular function will be without actually getting some objective data. And actually, if you look at the trend of test,

Starting point is 00:24:01 of semen quality decline over time kind of getting back to some of those earlier points you're making, if you were to overlay that on the known association between obesity, its effects on semen quality. That actually doesn't explain the whole decline because the purported decline in semen quality is about 50%. But if you were to say, well, what would we expect if we look at,

Starting point is 00:24:24 because we were able to track exactly how much fatter we are now than we used to be, that actually only explains about a 10% decline. So I think there is, to your point, something more. And it is not something that you can just identify by high. What are the do's and don'ts? as it relates to, I don't want to use the word optimizing. It's gotten me into trouble before because the word optimize or optimal suggests that there's

Starting point is 00:24:48 an perfect number that one should all attain, if possible. But in reality, optimal is a day-to-day thing, at least. But what should people avoid in order to get their sperm quality as high as possible, their testosterone level? Again, here I will have to be careful. I don't want to say as high as possible because some people, might not want excessive androgen, but at the high end of normal, perhaps would be the ideal for many people. What should people do? What should they avoid? And here I'm setting aside

Starting point is 00:25:24 any prescription clinical treatments such as testosterone injections or things like Chorionic gonadotrope, human corionic genotropin, things that we can talk about a little bit later. But what should every male be doing in order to optimize these health parameters? Yeah, so I think that there are some risk factors that we do. Like, we'll start with steam and quality. So we talked about heat. I think that's a big one. So like hot tub sauna is trying to avoid those, some, you know, light data on sea warmers.

Starting point is 00:25:50 Anytime, you know, we kind of get this external heat source to the scrotum, you know, the testicles are outside the body because they need to be a little cooler. So anything that warms them up can certainly be a problem. Could I just briefly interrupt there to ask? We've done episodes on sauna and some of the health benefits of sauna. is it sufficient for somebody to bring in a cold pack to the sauna and put that up in their groin? I actually have suggested that. That's actually what I do when I go into the sauna.

Starting point is 00:26:17 And I have suggested this on podcasts not just for people who are trying to conceive because it seems like heat, as you mentioned, is bad for sperm, not quite as bad for testosterone levels. But is it also true that heating the testicle too much is generally bad for endocrine function? in males and therefore if one is going to go into a hot sauna for 20 minutes or more to essentially cool the scrotal area. Yeah, I mean, I think the spermatogenesis or sperm production is certainly a lot more sensitive. You know, whether you can sort of thwart the effects of external heat with a cooling pack, I think it makes sense. There are studies that have looked at different ways to cool the scrotum and have compared, you know, semen quality before and after, and there's some data that may help. It just depends how long you're going to spend in the sauna and how cold, you know,

Starting point is 00:27:06 that pack is going to remain. So ice pack and in the sauna for 20 to 45 minutes. And is the ice pack still cold afterwards? Yeah. Yeah, they actually sell, and by the way, I have no relationship to any of these companies, but they actually sell cold packs that are designed to be worn in your shorts. So if you go to a, you know, I'll go to a Russian Banya every once in a while now. I guess I'm outing myself. Yes, I have a cold pack in my shorts when I go to the Russian Banya. But, but they have a sort of an insulation so that you're the cold the very cold surface is cold enough but it's not right up in contact with the scrotal skin because that could get um i want to make a bad joke and say you could get sticky uh that situation you don't want it getting so cold that it actually

Starting point is 00:27:49 would stick to the skin and then it could potentially damage the skin when you try and remove the cold pack so it has a thin insulating layer um and uh yeah that's essentially what it is yeah i mean frostbite the scrotum is not theoretical. It can certainly happen. So you do want to be careful. So, I mean, in theory, that should be adequate to sort of, you know, to decrease the risk of that particular effect. You know, I keep coming back to health, how important that is to maintain, you know, adequate sperm production, because I think these two are very linked. You know, there have been studies that show that men with more comormid conditions, so obesity, hypertension, hyperlipidemia. As these sort of stack up, we see a decline in testicular function, so lower testosterone

Starting point is 00:28:29 levels and lower sperm quality. So I think, you know, taking ownership of your health, I think, is important as well. You know, a lot of times fertility tends to be one of the first touch points that some men have with health care, you know, because generally what brings men to the doctor, it's usually pain or, you know, kind of a problem. So, you know, if men are in their 20s and 30s, getting ready to start a family or 40s in some cases, sometimes they haven't, you know, seen a primary care doctor. So some of these things, some of this relationship has not been established yet. So I think, you know, thinking about ways to start that, I think would be important too. And then I know you don't want to talk about testosterone, but testosterone is actually a

Starting point is 00:29:06 fairly common problem that we see in fertility clinics. I would say that, you know, estimates say maybe about one in 20 and fertile men are that way because of testosterone. So I think when, you know, people get testosterone in different places, and hopefully, you know, whatever provider you're getting it from tells you that one of the side effects of this is lower sperm production. It's actually been tested as a contraceptive. And, you know, with some other agents, it can actually be fairly effective. So we just want to make sure that, you know, if men are starting testosterone, they're doing it for the right reason, they're doing it safely. I think about testosterone replacement therapy. Although, as we were talking about before we started recording, I am really on a push

Starting point is 00:29:44 now to rename what people call TRT, testosterone replacement therapy, because indeed some people have low testosterone and need it replaced, the R and TRT. But I think what you're referring to, if I'm not mistaken, is that there are probably millions of young men and older men taking exogenous testosterone, injections, creams, pills, pellets, you know, any number of nasal sprays now, you know, any number of different routes of delivery of exogenous testosterone. And that dramatically reduces one's endogenous testosterone production and dramatically reduces one's sperm count and maybe even quality. We'll maybe talk about this a little bit later, but maybe even can there's, I've been told that it can perhaps introduce a DNA fragmentation within the remaining

Starting point is 00:30:36 viable sperm as well. So do I have that, Craig? You're saying that you see 1.20 men have issues with fertility because they are taking testosterone. Right. So their testosterone levels presumably are going to be high in normal or more, but they are doing presumably not testosterone replacement therapy, but they're doing what I call testosterone augmentation therapy, meaning they were somewhere in the 300 to 900 nanograms per deciliter range, but decided to start taking testosterone anyway, and then their sperm count essentially diminishes to nil or close to it. In some cases, yeah.

Starting point is 00:31:12 So, I mean, I think there's various reasons that you would take testosterone. I think, you know, some people have been treated, you know, years ago, and so they do need to replace testosterone, you know, but some people do it for augmentation. I just usually say testosterone therapy, just so it's correct. You kill the R. I like that. That's better than the T-A-T, which doesn't have very good. Okay, just testosterone therapy.

Starting point is 00:31:32 Yeah. Okay. But if you had, you know, for example, we take 100 of my infertile patients that come in to see me in clinic, at least five of those men will be infertile because they're on testosterone therapy. And some of them do, you know, have that suspicion. They say, you know, I'm going to level with you. This is why my levels are probably low.

Starting point is 00:31:49 But a lot of men were not told that, you know, when they started therapy. So I think certainly for reproductive age men, that's in a very important conversation to have because there can be some other ways that we kind of maintain sperm production. I think sperm cryopreservation is a good option for these men as well. Or there may be other therapies they can think about just because of reproductive toxicity. What about HCG, human corionic gonadotrop? And I hear about a lot of people who go on testosterone therapy who take HCG every other day or so. typically the dosages that I hear about because people write to me about the stuff all the time really it's one of the most commonly asked questions um i get many questions about many topics but i would say a full 10 to 20 percent of them are about um penises or testosterone um well is perfect then right exactly um so a number of those guys who are taking testosterone will be prescribed hcg and to stimulate sperm production, endogenous sperm production to maintain healthy sperm, presumably,

Starting point is 00:32:55 because they either want to conceive or intending to conceive in the future. Is that the best line of treatment for maintaining fertility while people are taking testosterone therapy? Yeah, that's one of the therapies that we use, and I think it can work well. You know, just a low dose, usually, again, for those that know, 500 to 1,000 units every other day is usually adequate. I'd like to take a quick break and acknowledge one of our sponsors, Athletic Greens. Athletic Greens now called AG1 is a vitamin mineral probiotic drink that covers all of your foundational nutritional needs. I've been taking Athletic Greens since 2012, so I'm delighted that they're sponsoring the podcast.

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Starting point is 00:33:54 are optimal and vital for microbiotic health. In addition, athletic greens contains a number of adaptogens, vitamins, and minerals that make sure that all of my foundational nutritional needs are met. And it tastes great. If you'd like to try athletic greens, you can go to athletic greens.com slash Huberman

Starting point is 00:34:11 and they'll give you five free travel packs make it really easy to mix up Athletic Greens while you're on the road in the car, on the plane, et cetera. And they'll give you a year's supply of vitamin D3K2. Again, that's athletic greens.com slash Huberman to get the five free travel packs and the year's supply of vitamin D3K2. So if somebody is not taking testosterone exogenously, they gotten their body fat level down to a point where they're not considered obese. So they're hopefully doing some cardiovascular exercise each week, maybe doing some sport

Starting point is 00:34:43 it was some resistance training too, with the intention of maintaining all around good health. Stave off, you know, cerebrovascular, cardiovascular issues. What are some of the other don'ts? I'm going to assume that smoking cigarettes or vaping cigarettes is bad. Are there any studies that have looked specifically at vaping and sperm quality or testosterone levels? And is there any evidence that smoking cigarettes is good for testosterone levels or sperm production? Because I'm guessing the answer is no.

Starting point is 00:35:12 I feel like nowadays we just say don't smoke, but the data or the data, who knows, maybe nicotine can help sperm. I have no idea. Right. It's possible. I don't think we have the data on that yet. But yeah, I mean, I think to your point, I think lifestyle factors are certainly a big one. And, you know, some of these, you know, potentially, you know, kind of unhealthy habits. So smoking is certainly something you should not do.

Starting point is 00:35:33 There have been, you know, lots of studies that do link that to, you know, lower quality. Again, all the different measures that we look at. Also looking at fertility, these men tend to have all. longer time to get pregnant. Alcohol, I think, is another very common question that we get asked as well. And I think for that, there's, you know, I think less of a strong association that we've seen. So there, you know, there have been some studies that show that very high levels of alcohol, and I guess that's sort of subjective what some would consider higher or not. But, you know, when you get above maybe 20 drinks a week, there have been some effects. But usually...

Starting point is 00:36:06 That's a lot of drinking. I would think that's a lot. Yeah, but some people don't. But yeah. I did an episode on alcohol. I think anything more than two, I know people are going to, you know, bulk at this, but, you know, I think any more than two drinks per week is where you start to see some negative effects on some health parameters. But, you know, I'm not a teetotaler. So, yeah. Yeah.

Starting point is 00:36:26 But when you get to this 20 drink, that's when we started to see some effects on semen quality. But, you know, the thing about that is that usually if these men are drinking 20, they're doing other things, too, smoking. There can be other drug use as well. So it's hard to tease that out. But in general, that's, you know, I think certainly anything in moderation is probably, you know, it's probably better. And so that's how I counsel patients. I think, again, it's very rare that I see men that are at that level, but I certainly let them know what I do. There's some new data coming out of that we've started to work on looking at if there are different sensitivities to alcohol.

Starting point is 00:36:59 So, you know, some East Asians have a mutation that leads to flushing. And so that may put those men at higher risk. When they mix alcohol, we may see some, you know, slightly lower sperm parameters. You mean skin flushing because they don't make alcohol dehydrogenase? Exactly. Yeah. And is it, I've heard about that in Asian cultures. Is there an Asian population, excuse me, but is there any evidence that other populations might have slight variance on alcohol dehydrogenase that perhaps maybe they don't lack it

Starting point is 00:37:30 all together, but they have, I don't know, they're hypomorphs for whatever genes. means alcohol dehydrogenase and therefore they don't metabolize it as well and therefore the toxic form of alcohol is active in their system longer. Is there any evidence for that? No, I think you're exactly right. I mean, I think the one that we think about is East Asian cultures where it can be, you know, depending on, you know, the region like Chinese, Taiwanese, probably about 40 to 50% of the population has, you know, mutation in the ALDH2 gene. But other populations and people of African ancestry. There's a rate of mutation, I think, I'm not going to remember the exact percentage, but I think a few percentage points, some individual with Hispanic ancestry, Ashkenazi Jewish ancestry.

Starting point is 00:38:17 So in this particular gene, there's a mutation, not the same one that East Asians have. But, you know, again, I think it gets to why a mutation, you know, where we see sort of negative effects would persist. And the hypothesis that, you know, millennia ago, potentially it, you know, gave some sort of benefit for maybe an infectious disease or something similar to cystic fibrosis why you know again this mutation would persist in our population if there's not you know some sort of advantage to those carrying it but we do see another you know other men as well so i think if you know it's a simple question do you flush if you flush then maybe alcohol may have you know more of a harm than than someone else and then you know i get kind of getting along the lines i think

Starting point is 00:38:57 drug use is also something that we should try and you know we do counsel patients about because that can also negatively affect semen quality. Do you think it's fair to say that, okay, moderation is best, but if somebody had the option to either not drink or drink in moderation, that they should not drink, would that be even better? Is there any evidence for that? I mean, it seems like nowadays we take the stance that not smoking at all is better than smoking a little bit.

Starting point is 00:39:24 Actually, when I was a postdoc at Stanford from 2005, yes, 2005 to end of 2010, you could still smoke on the Stanford campus. I'm not a smoker, but there was this collection of, I have to be careful what I say here. There was a particular group on campus of postdocs and graduate students that would colonize this little area outside the hospital and smoke because that's where you could smoke. That was eventually eliminated as a possibility.

Starting point is 00:39:50 You can't smoke on Stanford campus as far as I know. But they would smoke right outside the hospital. Actually, a lot of the hospital workers would take a cigarette on their break. This is very common. The irony, yeah, exactly. Yeah, and this was common all over the country, right? This isn't unique to Stanford. But nowadays, you just don't see that because it's not allowed.

Starting point is 00:40:06 And we hear don't smoke. It's terrible for XYZ and everything, every other letter of the Alp. But with alcohol, we tend to hear that if you're going to drink, drink in moderation, it's not clear exactly what number that is. But is it possible that zero alcohol is better for sperm and endocrine health than any alcohol? Or is that not a fair assumption? I mean, I think it's a good question. I think, you know, your point about tobacco is an excellent one because I think any smoking is bad. But alcohol, I think we don't have that data for yet. And so I think

Starting point is 00:40:41 it's harder for me to make that recommendation to patients, especially because, you know, people do it for different reasons. And if it's not necessarily going to help them, you know, it'll harm them in social situations or other things. Yeah, I usually just, I usually give the moderation one. Unless, again, for the very high drinkers, I definitely talk about that. other drug use, I'm going to assume that unless prescribed for post-surgical pain or something like that, that benzodiazepines, heroin, opioids, if any kind, are just bad for sperm and testosterone. I think we could probably make that a short discussion, right? Yeah. You know, I can't imagine any of that would be good for reproductive health. Yeah, that's true. I mean,

Starting point is 00:41:25 there's, again, you'd imagine, or maybe not, but there's not a lot of data on it. It'd be difficult to enroll or maybe easy to enroll, but a lot of those studies have not been done. But there's limited ones of, you know, people in rehab where they have shown, you know, these associations with, you know, addicts or users and lower quality. So, yeah, that's how we talk to patients. What about cannabis? I did an episode of this podcast about cannabis, and I did highlight some of the medical applications of cannabis. I also highlight that very high THC cannabis may predispose, especially young males, to later psychiatry. episodes. There are more and more data coming out about that all the time. I got a lot of flack for

Starting point is 00:42:05 saying that, but that's my take on the data. And I know a lot of people use cannabis recreationally and in a kind of pseudo-therapeutic way. I say pseudo-therapeutic because I think a lot of people use cannabis to manage their anxiety and as an alternative to alcohol for a number of reasons. What is the relationship between cannabis use and testosterone and sperm production, or I should say sperm quality, excuse me? Yeah, so this is also a very common question. Again, with a wave of legalization across the country, I think more and more men and women are exposed to it. So again, there's data that the more men are exposed to it can lead to some harm in terms of sperm morphology and sperm numbers as well. You know, one of the

Starting point is 00:42:57 sort of landmark studies was about 1,200 men, and it found that men that used cannabis daily had significantly lower concentration, motility, morphology compared to those that didn't use it. So I think that's generally how men are counseled, but there's also, you know, other data that shows really a null effect. And I think that it's, it goes into probably the composition, how men are taking it, the frequency, because a lot of that data is not well teased out in a lot of these studies. So, you know, I think I sometimes struggle with this with patients because some of them are taking it for, you know, some what they consider legitimate reasons, anxiety, sleep, pain. And if there's not sort of very convincing evidence that it's going to help, and they're taking

Starting point is 00:43:42 it maybe lower than the threshold where I know that there's good data that'll cause harm. You know, I guess I'm trying to be sort of honest about where we are. But I think with a lot of things related to sperm, I think our level of evidence is not great. Are there any common over-the-counter medications that can negatively impact sperm quality and or testosterone? Things like non-steroid anti-inflammatory, drugs, talanol, ad-vill type stuff, you know, ibuprofen acetaminophen, things of that sort that I and others might not be aware of. I'm not probing for anything in particular here.

Starting point is 00:44:17 I just, I know that, you know, a lot of over-the-counter drugs have. effects that we're just simply not aware of yeah i mean i think we probably need more data but i think currently we think all those are safe i'm curious about the pituitary pituitary gland as many the listeners of this podcast already know is a gland that receives signals from the brain um the gland sits near the roof of the mouth um i think that's fair um and releases critical hormones into the bloodstream that control the output of testosterone from the testes as well as output of hormones from other glands. I know a number of people will end up playing sports like football or rugby or even lacrosse or

Starting point is 00:45:01 even soccer I've read. There are data on this. You know, they're heading the soccer ball quite a lot or martial arts or they get a head injury at some point. And I certainly hear a lot from people who played these high contact sports and that to their surprise, later they have diminished testosterone levels. I also work with a number of military groups that talk about this, you know, that they leave and maybe it's from combat-related stress, et cetera, but they wonder whether or not there's any traumatic head injury or maybe

Starting point is 00:45:36 pituitary injury related impairment to the reproductive access that includes brain, pituitary, and the testes. Do you see that? And if somebody played a contact sport, in particular contact sport where the head was hit or they were hitting things with their head often, or if they have a TBI or had a TBI, that their reproductive health can be impaired. That's fascinating. I have not. I mean, I think, you know, it's interesting, I guess, you know, what the pituitary does. You've obviously covered this before, but it does go to a lot of our therapies.

Starting point is 00:46:11 I mean, so, you know, for your listeners, you know, that pituitary produces two hormones, LH, lutinizing hormone, and FSAH, follicle stimulating hormone. which then stimulates the testicle. So the lutonizing hormone stimulates the latexels to make testosterone, and then the follicle stimulating hormone, or FSH, stimulates sperm production. So both of those are very key in terms of production. And interestingly, when exogenous testosterone is used, you know, it shuts down that axis, as you know.

Starting point is 00:46:38 So we get less of these gonadotropins, this LHFSA to stimulate the testicle. And the other sort of reason that sperm production is lost with exogenous. testosterone uses it is actually the intracisticular testosterone is much higher than serum levels. So, you know, our serum levels are, you know, between 300 to 900 nanograms for decilator on average. But in the testicle are probably tenfold higher at least. So when men are given exogenous testosterone and they're not producing their own, the levels of testosterone in the testicle, which are necessary for sperm production are much, much lower. But it's interesting because I think I'm not aware of sort of how traumatic injuries would do that.

Starting point is 00:47:23 Okay. That's good to know. I'm curious about the non-endocrine, non-chemical effects on sperm quality and testosterone levels. So here I'm thinking about a bunch of news stories we heard a few years ago about how bicycle seat pressure on the prostate, or maybe it was other portions of the, it was the nerves running to the penis itself or surrounding areas, maybe it was pelvic floor related and somehow you'll tell us, I'm sure,

Starting point is 00:48:00 was impairing sexual function? Was it impairing sexual function in any way by impairing testosterone levels, cutting off blood flow to the testes? And here, perhaps the most important thing to ask straight off is riding a bicycle bad for male reproductive health and sexual health. Yeah, these are great questions.

Starting point is 00:48:20 Again, living in the Bay Area, working in the Bay Area, cycling is very, very popular. So these are questions that I get a lot. So I think, you know, in general, like we talked about before, anything that's good for your heart, it's going to be good fertility. So good diet and exercise, maintaining good body weight. And so I always try and encourage physical fitness. I think that's important. But, you know, it may be possible that some particular activities may put men at more risk.

Starting point is 00:48:47 So I think cycling could be one of them, but it would sort of depend on exactly why we think that may be a problem. So I guess the theory is heat. If you're in the saddle for a long time, you know, for these prolonged, you know, rides that men take, you know, on weekends, you know, hours. That may be if there's too much heat exposure, that may be the mechanism where sperm production would decline. So there have been some studies say maybe five hours a week would be, you know, that may be too much. So if you're above that level, the sperm counts shown to be lower. If you're less than that, that may be okay. So when I talk to patients about it, I try and just encourage them to, you know, stand up in the saddle to try and, again, sort of air things out to try and dissipate heat.

Starting point is 00:49:26 If that's the mechanism we're going to think. Regarding sexual dysfunction, that is thought to be pressure, as you're alluding to. So, you know, the way that the saddle is configured, ideally all the pressure is put on our ischial tuberosities or our sit bones. That's what I'm sitting on now. But on the saddle, you know, there's obviously kind of the rigid nose. And if there's too much pressure on that, that actually squeezes between the iskeletuberosities where, you know, the main blood flow to the penis goes and the main nerve supply is, too. And so if there's compression on this, you get this sort of lack of blood flow or ischemia,

Starting point is 00:50:01 and you can get a neuropraxia as well if you crush these nerves. And so that over time can lead the problems. So, you know, some patients will say that, you know, after I cycle, you know, things are numb down there for 30 minutes or a day. or I don't get erections for that sort of the same amount of time, or sometimes, you know, men just sort of, you know, ride through it. And, you know, hopefully things come back in a day or two. So that's, that could be the mechanism.

Starting point is 00:50:27 There are some saddles that, you know, hopefully it will be a little safer. And, you know, I think that this sort of first was noted probably around 2000 or so. And there is a big redesign in terms of saddles to try and make them a little bit more, you know, anatomically correct to try and minimize some of this. And there's cycle fit that can be done or saddle fit, rather, that can be done at some of the cycling shops. To try and, you know, look at your body position, look at your size, and try and find a saddle that's safer. You know, not this doesn't happen to everybody. I would say maybe if you were to survey cyclists, maybe 20 or 30 percent of men and women tend to be susceptible to this.

Starting point is 00:51:06 So I think if you are having discomfort when you cycle, whether it be pain, numbness, or you notice dysfunction, I think certainly you should, you know, think about changing saddles or think about changing writing style. There's other strategies they're sometimes used, but, you know, it's absolutely something that everybody should be aware of. I meant to ask this earlier, but I seemed to recall a study that drew a correlation between amount of walking, and maybe it was sperm quality, but I think it was testosterone levels. Maybe some other metrics of male sexual health. Forgive me, I'm not recalling the details now.

Starting point is 00:51:42 Is there any evidence that walking more, standing more, maybe even using a standing desk, is beneficial for pelvic floor health, blood flow, prostate health, who knows, could be any and all of those things in some way that is beneficial for sperm quality, testosterone level, and or overall male sexual health? Yeah, I think, you know, one of the ways that we can characterize activity is step count, I think I have a watch that tells me that something that I look at every day and kind of strive for. And it turns out that the more active you are, it's been shown sort of looking at, you know, large national data pools across different age ranges that it is associated with testosterone levels.

Starting point is 00:52:25 So being more active, I think, is very important. And that's another thing that, you know, everybody can do to try and improve sort of testicular function broadly, but testosterone specifically. And do you know whether or not that can be separated out from the relationship between being more active and less obese? I mean, is this something that's independent of obesity? In other words, can we incentivize people to walk more simply on the promise of improved sexual health? Well, I don't know. Sexual health will be a different one, but we can, I think, there is association between testosterone levels and step count across different BMI straight up.

Starting point is 00:53:02 So I think, you know, whether you have the ideal body weight, whether you have a few pounds to lose, perhaps, if you walk more, you will see higher levels of testosterone. Okay. And another question I meant to ask earlier, and then we can close the hatch on exogenous testosterone therapy, at least for the time being, maybe we'll come back to it, is assuming that somebody can maintain adequate sperm production through the use of HCG or some other therapy, or perhaps they don't care if they're still making sperm because they've already had children or they don't care to have children. Maybe they've banked sperm in any event. assuming that somebody takes testosterone therapy because they were prescribed that, let's say in your clinic. Let's just use you and your clinic as an example. And they are happy with the psychological and physical consequences of that and they are comfortable with the tradeoffs.

Starting point is 00:53:54 Is there any increased risk of, say, prostate cancer or other forms of cancer? And here I'm going to assume that this person is keeping their lip-off. levels in check, because you hear about some hyperlipidemia with testosterone therapies. Let's assume that they're either taking a statin or they're not taking a statin and they're getting enough cardiovascular exercise that things are in check in terms of LDL, HDL, APOB, and all of that. And their testosterone levels are now high normal and they're feeling better. And they don't have to worry about sperm production because they're either maintaining it

Starting point is 00:54:27 or it's been banked or they don't care about that. Is there an increased risk of prostate cancer? My understanding is the answer is no, but what's the real deal? Does taking testosterone therapy, assuming all other things are being held in check, in a healthy check, does it increase the risk of any kind of cancer? Yeah, I mean, this is another great question because I think there's a lot of myths around testosterone, and that's one of them. You know, the origin is that prostate cancer is thought to be or is sort of androgen mediated. You know, one of the Nobel Prize, you know, again, decades ago, was awarded because it was found that when we lowered, a man's testosterone, the prostate cancer would regress dramatically. So that put that association between

Starting point is 00:55:09 testosterone and prostate cancer. So then the concern began if we were to either replace testosterone or augment testosterone and give a man testosterone, is that going to alter his risk or increase his risk. So I think we have pretty convincing data that that's not the case. You know, there's lots of longitudinal data spanning decades where if man is given testosterone, it doesn't change his risk. The reason for of that, in sort of seeming contradist, you know, this contradiction between, you know, prostate cancer, a therapy where we lower testosterone, where if you give a man testosterone doesn't change this prostate cancer risk is not certain, but there's this popular model called the saturation model, so that once there's enough testosterone in the body, and it tends to be a fairly

Starting point is 00:55:52 low level, that all this sort of the prostate testosterone receptors, you know, you can kind of think of as have been filled. So if you were to give man more testosterone, doesn't change anything regarding the prostate cancer, prostate growth, any of that. So it is safe when we're looking at prostate cancer as an outcome. Getting back to prostate health and neural innervation of the penis and blood flow to the penis, you mentioned the bike seat-related issues. Are there other things that men should do in order to maintain prostate health, stave off prostate diseases, and to maintain healthy blood flow and neural innervation of the penis for obvious reasons,

Starting point is 00:56:35 and we'll get into the specifics of those reasons in our later discussion. Yeah, I mean, I think that, you know, I always kind of think of the penis as a user or a loser organ. So that doesn't mean necessarily you have to have sex. But, you know, normally we get erections every night, so that should be maintained. And if there's any reason to sort of suspect that that may not be going on, And usually in my practice, that would be from, you know, some pelvic surgical intervention or something like that. Sometimes we can intervene to try and maintain that.

Starting point is 00:57:03 You're talking about spontaneous erections during sleep. Right. So, and short of assigning one's partner to check frequency and tumessence, what is the way that men would know that that's happening? Are you talking about waking up with an erection? Is that requisite for knowing that nocturnal erections are? occurring? Well, yeah, I think you kind of caught me. I think that's a good question. So I think a lot of times you won't know, but I think if you have sort of normal response, you know, when

Starting point is 00:57:33 either by yourself, with a partner, I think that generally means that you are going to get normal erection. So I think, I guess when I say use it or lose it, it doesn't mean necessarily that the man has to stimulate himself or kind of make sure that he does have, you know, adequate function. because usually most of that normal function just occurs, you know, with this nocturnal penile tumetum essence, which we all get. You know, I think sometimes men do notice when they wake up at night. Sometimes in the morning you wake up with an erection and men notice that. But the absence of that doesn't mean it's not happening. It likely is just, you know, most people sleep through it, which is normal.

Starting point is 00:58:07 Otherwise, men would never get any sleep because it happens many, many times at night. So I think, you know, again, if you're not having normal function, I think that's something you should probably see, you know, a physician about. And then same for like urinary function. I think if it bothers you, if there's, you know, if you're waking up at night, if you have to go to the bathroom often, if your stream is getting weaker, those are all sort of complaints that we hear about. What is often? My understanding is that it's normal to wake up perhaps once during the night to urinate.

Starting point is 00:58:38 And this is, of course, assuming, and again, forgive me for all the caveats, but I've done this long enough that, you know, if I don't get really granular about some of this, then she was like, well, what if I drank, you know, 32 ounces of fluid right, before sleep and I'm urinating three times per night. Well, we're assuming that people are tapering their liquid intake as they approach bedtime. And that waking up once, maybe twice, but once in the middle of the night to urinate is normal for somebody, let's say, age, I don't know, 18 to 40. And maybe from 40 to 100, that number might be in the one to two times per night. Is that about right? Yeah, I mean, I think once a night, yeah, is normal for most men. And then I think if things start

Starting point is 00:59:19 to bother you, I think you could certainly see somebody, but it's hard to get better than once or twice a night for most men. My understanding is that there's a pretty good relationship between the nocturnal erection and the amount of REM sleep, rapid eye movement sleep that one is getting. This tends to be more frequent toward morning as the proportion of rapid eye movement sleep increases. I don't know if that's true or not, but I found a couple of studies that at least point in that direction, no pun intended.

Starting point is 00:59:46 So that raises a bigger issue that we haven't talked about yet, which is getting adequate amounts of quality sleep each night. And I think for most people, that's seven to nine hours, ideally, which means getting sufficient slow wave, deep sleep, as well as rapid eye movement sleep. But nowadays, a lot of people, including young people who are not working excessive hours, are getting four, five, six hours of sleep per night. But is there a direct relationship between getting less than sufficient amounts of sleep and sperm quality testosterone levels and sexual health? Yeah, I mean, I think certainly there's reasonable data for semen quality. And there tends to be, you know, we call like in science sort of a U-shaped relationship so that it's not sort of linear.

Starting point is 01:00:34 So as you get more sleep, things are better. There's sort of there's this concept of too much sleep and not enough sleep. So the ideal, I think, as you pointed out, is seven to nine hours. And for men that are not getting that, semen quality tends to be lower. And then for men getting too much, we also see a decline. And, you know, why that is, is, again, not certain. Again, if you're able to get that much sleep, maybe there's other things as well that we should look at. But so I think kind of getting in that ideal sleep amount is best for semen quality

Starting point is 01:01:04 and probably for broad to stick out function as well. You keep bringing up semen quality in a way that makes me wonder whether or not, Is semen quality a proxy for overall vitality and health? Or is testosterone level a proxy for overall vitality and health? It sounds like semen quality is the metric that you keep coming back to in a way that I have to assume reflects your, you know, your clinical experience and the many papers that you've authored in this area. I think for people that hear semen quality and who are not interested in conceiving children now or who are. which of course could include people who've already had children or who don't want children, semen quality sounds like something that relates to fertility.

Starting point is 01:01:54 But is semen quality something that is a good goal for those who are interested in overall male vitality and health? Is it one of the better metrics of overall male vitality and health? Well, I think, you know, I think it's an excellent marker for overall health. I think there are studies that support it can be a measure of how healthy you are. You know, if you look at men with more health problems, they can have lower semen quality, but also if you look at semen quality just by itself and then you look into the future how these men tend to do. If they have higher semen quality, they tend to live longer, need to go to the doctor less, lower rates of cancer.

Starting point is 01:02:33 So I think there's a lot of different ways that semen quality may be a good barometer of health. you know, why that link exists, I think, is not known, but there's lots of theories. So one is that, you know, probably about 10% of the male genome is devoted to reproduction. And so it makes sense, given that we only have about, you know, 24,000 genes in the body, that there's a lot of, you know, overlap. So one gene that plays a role in reproduction may play a role in, you know, the cardiovascular system or the neurological system. And so if we get the first, you know, sort of sign that reproduction is not perfect, there may be some other health consequences down the line. Another sort of hypothesis is that, again, sort of going along this line, that reproduction is one of the first things that we see is that, you know, gestation is sort of very critical to our, you know, existence, right?

Starting point is 01:03:26 And if perturbations to that system have prolonged, you know, effects, sort of the so-called sort of developmental origin of adult disease or the bark hypothesis. And so we know that, you know, premature children have higher risk of cardiovascular disease or urban studies to show that. But we also know that, you know, these gestational effects can also play out on reproductive function too. So that also may be kind of a link, you know, sort of early seating of reproductive function. And then that's maybe the first marker that we're going to have for other health effects later on. There are also just sort of inherent sort of similarities between reproduction and some other sort of social effects. So, you know, kind of one sort of confounding factor, when we're looking at some of these

Starting point is 01:04:11 studies I talked about looking at mortality, for example, and semen quality, is that, you know, there's sort of factors that necessarily involve reproduction. So your children and having a partner. And having a partner prolongs life, having kids prolong life, even though it feels like kids are killing you. If you look at studies, men with kids tend to live longer. So, you know, that's another possible explanation. But I think, you know, really sort of this health, you know, link between fertility, I think is sort of a powerful one.

Starting point is 01:04:43 So I do think it should be a barometer. I think that, you know, it should be sort of when I've given lectures on this, I call it the sixth vital sign. I think it's something that we should probably check because if there is, you know, sort of lower levels, that may tell us about something else going on. You know, when men come in for infertility evaluations, a lot of time we do diagnose. you know, these new medical problems. Sometimes we diagnose cancer, you know, sort of alluding to some of the questions you've asked, diabetes, and some other, you know,

Starting point is 01:05:10 very significant genetic conditions as well. And, you know, the first way that we would identify it is reproductive failure because their sperm counts are low and other things. So it is something I think that it's sort of, it's very important, I think, for people to realize. And it would be great. I think, you know, another, I think,

Starting point is 01:05:29 advantage to like the Centers for Disease Control, for example, tracking it? Would it be a good idea for males in their 20s and 30s to get a sperm analysis, just to have a baseline? I confess I'm 47 now. One thing I wish I had done in my 20s was to get my blood hormone profiles and lipid profiles done when I was in my teens and 20s because I'd have something to compare to. I started doing that in my mid-30s, and I'm so glad I did because I can now compare to my mid-30 levels. I started including sperm analysis about eight years ago. with the intention of freezing sperm and did that because I was also reading at that time

Starting point is 01:06:07 about the increased risk of autism in offspring of males older than 40, something that I really would like your take on. But it seems like it's inexpensive enough to do a sperm analysis. I think now people can get it done at home. They have mail mail kits, although I don't understand how the motility could be maintained if you're mailing your sperm back at room temperature or it's heading through the post office now everyone's imagining all these sperm traveling through the postal service it's out they're out there folks um yeah what are your thought should um should people invest the i think it was a couple hundred dollars to get a sperm analysis more costly to get the DNA fragmentation then you get up into the low thousands um but if people

Starting point is 01:06:54 have the disposable income is it a good idea for them to do i mean i think it's a worthwhile test. I think more information is always good. You know, I think sort of one of the same reasons that, you know, you're talking about checking like lipid levels or we tell, you know, men and women to get blood pressure checked. I think, you know, getting that sort of early health indicator, I think can be important. I think, you know, going back to not knowing exactly why semen quality is telling us about health, what the exact link may be, you know, means that if somebody is coming in with a low sperm count or completely absent sperm count, it's hard to know exactly how to counsel that person other than the maybe reproductive difficulties.

Starting point is 01:07:33 But I think just as sort of a marker for reproductive potential, I think it's useful. And like you said, I think it's become a lot easier. One of the innovations in the space, and, you know, somebody that, you know, is in the reproductive world, I think it's just really great to see sort of this influx and capital and new companies coming in that trying to just decrease the barrier to, you know, getting a cement test. It used to be you have to go to a lab, schedule an appointment. sometimes they would send you to a bathroom which can be uncomfortable you know because people are doing you know what people do in a bathroom just next to you or you're trying to collect

Starting point is 01:08:04 oh they would send them into a in a common space bathroom they wouldn't even give them the quiet room with the with the red light which is uh right what i hear they do now yeah some of them do have videos so there are some higher level oh i didn't even mean videos i just i think that um okay yes i've done this i'll just say i mean i'm trying to normalize things related to all aspects of mental health physical health. So, yeah, I decided to free sperm and basically they sent me to a room. I went to a university-based clinic. It actually wasn't Stanford, but different university.

Starting point is 01:08:35 And, yeah, they put the cup through the window. They give you the cup. They closed the door and they tell you that as long as that red light is on over the door, no one's going to walk in. And then they leave. And I think the assumption now is that you figure it out one way or another how to provide the sample and then you put the sample back through the thing. And then one thing these clinics really need to work out is that anytime you're walking out, you see the people processing

Starting point is 01:09:01 your sample as you walk out. So there's all this feigning of, you know, anonymity. But really, it isn't there, you know, because they're like, see you later. And you're like, great, you know, they rarely ask you questions on the way out. But it's a pretty simple process overall. And I must say that the data are informative. You get the, you know, you get the volume. number motile, forwardly motile. I did opt for the DNA fragmentation data. And I just love data. So I think it's really interesting. But again, maybe this is a good time to flag this, this set of findings. I believe that there seems to be a small but statistically significant increase in the number of autistic births due to pregnancies where the male was over 40 at the

Starting point is 01:09:48 time of conception. So I figured, you know, why not freeze some sperm and it's relatively inexpensive. Yeah. Yeah. So I think paternal age is also, you know, something that's increasing in this country. So over the last 40 years or so, we've seen that the average paternal age has increased from about 27 and a half to about 31. And I should say that this is all fathers.

Starting point is 01:10:13 So birth certificate data, birth data, is collected at a maternal level. So, you know, when a child is born, somebody comes to. in to collect data on the birth. So they ask, you know, all the characteristics of the mother, and they also ask characteristics of the father, you know, age, education, obviously, region of the country, the child was born. So we don't know, you know, what number child that was for the father. We know it for the mother. They do ask, you know, this is your first, second, third, et cetera, child. So the father, unfortunately, we just have data that sort of all lumped together. But over the last, again, 40 years, we've seen that increase.

Starting point is 01:10:46 Interesting, over the last 40 years, the youngest father was 11, and the oldest was, 88. 11. Quite a span. Yeah. 88. Goodness. Unrelated.

Starting point is 01:10:56 I don't know. I assume. Goodness. It's anonymized data. But 11. I have to ask this. Sorry to take us on a slight tangent, but what is the average age of puberty in males in the United States now? Yeah.

Starting point is 01:11:13 So you're asking about, I guess, sort of sperm-marky, when like sperm production begins. So. Yeah. There are a lot of markers of puberty. secondary sexual character is beard growth deepening of voices. They happen at different rates and different people. But yeah, thank you. At what point are males undergoing puberty at the level of that we're talking about here?

Starting point is 01:11:35 Yeah. So it's, yeah, there has been data that we're going through puberty a little bit earlier now than we used to. But it really varies. So, you know, I think it's not, you know, just like testosterone ranges between like 300 and 900. That's a wide range for anybody. I think for most individuals, you know, puberty is, you know, probably 12 to kind of 15, 16 in general. So I just give sort of a very wide range when we're going to say that's okay. And, you know, some of the data I'm basing it on is when sperm production begins in boys.

Starting point is 01:12:04 And it's actually, you know, not that simple to be able to figure that out because, you know, we don't generally talk to, you know, young boys about how to master, how to collect and then check on that. But there's something called first morning voided urine where we can actually look at that. And there have been some studies done, and they see if there were sort of nocturnal emissions, whether there's sperm in there. And so generally, it probably starts around the earliest would be kind of 11, 12, 13, but usually most is probably a little later. So maybe I'll refine that puberty and move it a little bit later, probably 14 to 16, is

Starting point is 01:12:39 when probably about 70, 80 percent of boys are going to have produced, started producing sperm. My understanding is that in females, puberty is also shifting earlier. perhaps at a more dramatic rate than appears to be the case for males. Well, I think there is some data for males too. I think, but again, for your listeners, I don't want to have this onslaught of pediatricians seeing kids that haven't, you know, when boys haven't gone through puberty by a certain age. So I think it's still fairly wide. Let's get back to age of the father and issues like autism.

Starting point is 01:13:15 What are the data there? this to me is a practical issue because I think if there's one obvious takeaway from our discussion today, it's that males should probably not wait until they're trying to conceive in order to assess their reproductive health at the level of sperm quality, testosterone levels, perhaps, but at least sperm quality. But perhaps men should also be freezing their sperm if, in fact, conceiving children after 40 places their children at far greater. risk for autism. My understanding is that the rates of autism are somewhere between 1 and 80. You'll hear as high as 1 in 50 male bursts, but I think it's probably more like 1 in 60 to 80,

Starting point is 01:13:57 is that about right? And that the age of the father is a risk factor. Yeah, I think that this gets into sort of the larger issue of, you know, how men sort of perceive fertility. So, you know, we know that as women age fertility declines, but the oldest father ever is 96. So the biologic potential certainly persists. Wait, I want to know how long here. He lived to see how long his child to grow up. He conceived at 96. Supposedly. Supposedly, yeah.

Starting point is 01:14:25 Well, I'm assuming he did not meet his grandchildren, at least not the grandchild of that child. So, wow, how long did he live? You know, well, so this is a man in India. It's just sort of a famous story. But supposedly he had a child. He had that child with him on, like they're waiting at a bus stop. He fell asleep. The child was kidnapped.

Starting point is 01:14:46 I led to divorce. so yeah dreadful sort of a horrible end but the wife was also old not not that old but in her 50s so yeah wow um tragic and and incredible story for separate reasons um okay i'll get my head around this 96 year old uh conceiving a child okay um please continue yeah uh so people i think or men think that the sort of the um you know they're you know for fertile road is sort of infinite. But I think that's very much not the case. So as you're alluding to, people have looked into risks for older fathers. So, you know, about 100 years ago, was first noticed that dwarfism or chondroplasia was more common in lastborn children.

Starting point is 01:15:31 So eventually that link was made. And since then, other conditions, too. So there's like these neuropsychiatric conditions you're talking about, like autism is certainly one, bipolar schizophrenia. People have looked at and also linked that with older age, you know, less attainment in school, you know, failing grades, all that has been shown to be a little bit more common with older fathers. So, you know, why I think all these exist, there can be sort of different explanations. You know, one explanation for the autism association, I'll talk about, you know, some of this more genetic or kind of mutational reasons, about one thing that some people say is that, you know, it could be sort of a hereditary trait. And so it may be that, you know,

Starting point is 01:16:15 you know, men that display some sort of autistic characteristics. You know, maybe they take a little longer to meet a partner, and so it sort of delayed childbearing. So maybe that's one possible explanation. But I think, you know, there's been a lot of convincing evidence that there could be, you know, real epigenetic changes that occur with age and mutational changes that occur with age. I think I read a statistic and you would know more being a neuroscientist

Starting point is 01:16:40 that 84% of the genes in our body expressed somewhere in the central nervous, system? Is that? Sounds about right? Yeah. Yeah. I don't want to stamp my name to that. But that sounds about right. So it's estimated that every year we generate about two mutations in our, you know, sperm DNA. So you can imagine that, you know, a 40-year-old is going to have, you know, 20 or 40 more mutations than a 20-year-old. So that rate does go up. And if you're just randomly sprinkling mutations, you know, in, you know, a genome that they're more likely that sort of manifest in, you know, maybe neuropsychiatric conditions. So there are, you know, data, convincing data that shows that that does occur. Now, again, there's billions of base pairs in the body, so these random mutations likely

Starting point is 01:17:32 most of them will not result in anything, but there can be some meaningful ones. So, for example, a chondroplasia's due to a mutation in fibroblast growth factor receptor. And what's interesting is that this condition is not that rare, right? Based on sort of these rare mutations, you'd expect this would, you know, occur maybe about one in a hundred million, but it turns out these conditions occur in about one and I think 30 to 50,000 or so. So there's sort of the discrepancy based on sort of mutational rate that we expect based on age and the rate that we actually see. So the explanation for this is something called selfish spramatogonal selection. So what this suggests is that some of these mutations that occur randomly occur in proliferation pathway.

Starting point is 01:18:14 And so it gives the sperm that contain these sort of advantages over their, you know, brothers and sisters that don't have them, for example. And so then they outcompete the other sperm. And so they're more likely to lead to a child rather than sort of a random smattering. And you can actually see that some of these mutations are more common in older men than younger men. If you look, you screen for some of these mutations and, you know, some of these pathways. Again, the longer that we're exposed to life, there's just more likely to be, you know, different chemical exposures or other exposures. And so people have looked at epigenetic signatures, sort of these signatures that, you know, that dictate which genes are going to be expressed and which aren't.

Starting point is 01:18:50 And there are different patterns between older and younger fathers. And, you know, what triggering those is not known, but there are differences. So those could also potentially explain, you know, some of these risks that we see. You know, it used to be that people thought that, you know, if you're an older father, maybe there's a lot of advantages, you know, for the kids, right? Because if you're more resourced, right, I always tell patients that, you know, when they come to see me, correction problems or anything. I always say nothing gets better with age, right? And that's mostly true, although they pointed out that salary often goes up with age and wisdom goes up with age.

Starting point is 01:19:21 So you'd imagine if you're more resource, maybe the kids are going to also have an advantage to that. But, you know, again, there's a lot of convincing data that that's probably not the case. There's even there's one study that I saw that showed that if you look at MRIs of brains, of children, just after birth, they're actually a little smaller for older fathers compared to younger fathers. So I think there are some, you know, sort of talking about kind of neurocognitive development, some of those effects. And there's also been studies looking at cancer risk too. So higher risk of breast cancer, prostate cancer, and adult children, higher risk of, you know, leukemia or CNS cancers in children as well. So I think the more we look, the more we find out of these associations with paternal age.

Starting point is 01:20:08 So I think it's something we certainly be aware of. I think you're talking about mitigation strategies, I think sort of education would be important for couples to try earlier, individuals to try earlier to conceive. You know, if we think it's a mutational reason, I think, certainly freezing sperm, I think, is a good option as well. My understanding is that analysis of DNA fragmentation in sperm does not allow for selection of the best sperm on the basis of DNA composition, translated to, English, what I mean is in order to tell whether or not the DNA are mutated in a sperm,

Starting point is 01:20:43 you have to kill the sperm, basically. So, and since in a given pool of sperm, so to speak, there will be forward motile, non-motile, twitchers twitching in place, dead sperm, some percentage of dead sperm or immotile sperm is presumably normal, some small percentage, hopefully, and that some might have some DNA fragmentation, some might not. So, is the way to address this averages. What I'm hearing here is that if you haven't already had kids or if you want more kids, that you might want to know about your sperm quality, I would say you do, and that if you can afford it, you might want to take a look at DNA fragmentation data.

Starting point is 01:21:28 But having done this, what one receives is a chart that goes from red, bad, to green, good. And then they put the arrow, hopefully in the green zone. And then you say, oh, good. I'm in the green zone. I don't have fragmented DNA in my sperm. But really, that's an averaging of all the sperm, right? It could be that as you age, that some percentage of those sperm have fragmented DNA. And if one of those is the one that successfully wins the egg, so to speak, fertilizes the egg, then that fragmented DNA containing sperm is going to propagate that into your offspring. So are there any technologies that can allow men to

Starting point is 01:22:09 select or for or improve the DNA of their sperm, not just the motility? Yeah, I wish, right? That's sort of the holy grail. Because I think you pointed out sort of a variant of right, the Heisenberg uncertainty principles that we can't, if we identify which sperm is bad, we're necessarily going to destroy it. So to tell, you know, which one is harboring these mutations would be great. But I think we're not there yet. I mean, one thing that we do do is wash sperm. So we do sort of select the most modal sperm. We clear out the dead ones. And I think embryologists are pretty good at telling which sperm they think are better. But again, we don't have any real objective data to try and understand, you know, which you're harboring something or other.

Starting point is 01:22:48 But I think if we understood more about this link with age or, again, other conditions, hopefully we would be able to stop some of this pass through. Let's get back to the prostate, this incredible gland. Tell us about the prostate. I think we hear about the prostate. We hear about prostate cancer. people might have heard that it's involved in the ejaculatory response. It's involved in erections. It's involved in a number of things. If you give us a, you know, a catalog of things that the prostate does, I mean, you spent a lot of time thinking about this gland. What are some of the cooler things that it

Starting point is 01:23:22 does that we don't know about? You know, how do we keep it healthy? And what are the consequences of not keeping it healthy? Yeah. So the prostate is a gland about the size of a walnut. It sits behind the bladder, and it's involved in reproduction. It produces some of the proteins, enzymes that are necessary for, you know, sperm to be supported and, you know, the ejaculate to kind of keep the sperm healthy in the female reproductive tract. So, you know, it functions in reproduction. And then basically after reproduction is done, it doesn't really serve any useful function. So then it just becomes a problem, essentially. So the erythra, which is where we pee through, so it connects the bladder, you know, to exits the body, runs right through the prostate. And as we age, the prostate does get

Starting point is 01:24:07 bigger. That's sort of a known thing. And as the prostate gets bigger, it creates sort of more resistance in this pipe. And so it makes the bladder out to work harder. And that leads to a lot of the symptoms, you know, that we've been talking about already, you know, waking up at night, week stream, this need to urinate urgently, sometimes feeling like you're not emptying all the way. So it's sort of a consequence of the prostate sort of being there. In terms of ways that you can keep the prostate healthy, I think that there's really nothing that, you know, necessarily you can do. I think that, you know, one thing I talk to patients about when these sort of symptoms start is to know some of the triggers. So, you know, like you mentioned drinking a lot before you go to

Starting point is 01:24:45 bed. So if you don't want to wake up at night, that's not a good practice. You know, may even want to go into bed sort of a little dehydrated just so you can try and last the night. There are some, you know, particular drinks or foods that tend to be more irritating. So like spicy foods, acidic foods, those can sometimes irritate the lining of the bladder and make you have to pee a little bit more. You know, caffeine is a diuretic, so it makes us urinate more, and it also can also irritate the bladder and give you that sensation of alcohol. We'll do the same thing. So I think, you know, kind of knowing some of those triggers may kind of stay off some of the symptoms a little bit. But, you know, again, if you enjoy those vices and you're willing to

Starting point is 01:25:21 tolerate it, that's okay, too. I'm hearing more and more about a practice of people taking low dose to Dallifil, Cialis, low dose, meaning in the neighbor. of 2.5 to 5 milligrams per day, not necessarily for erectile dysfunction, but for prostate health, and was somewhat surprised to learn that those drugs were actually developed first for treatment of prostate health to increase blood flow to the prostate. Is that true? And is there good reason to think about taking 2.5 to 5 milligrams of to dalafil per day simply for maintaining blood flow to the prostate and thereby maintaining or improving prostate health. I mean, certainly it can do that. It can definitely help with some of these urinary symptoms

Starting point is 01:26:10 that we've been talking about. You know, looking at placebo-controlled trials, sort of a high level of evidence, does show that, you know, low dose of to dalafil, these two and a half to five milligram, these daily dosing can help with these urinary symptoms. So I think that not necessarily as a preventative measure, but for men that are bothered, you know, otherwise I think most men probably wouldn't want to take a pill every day, but certainly if you have some of these symptoms, it can definitely help with urinary bother. And then the added benefit, as you also alluded to, is it can help with erectile function as well. Even at the 2.5 to 5 milligram dosage. Interesting. Yeah, my experience is that there are a lot

Starting point is 01:26:45 of people who would love to take pills every day. There seems to be a kind of binary distribution where, and here I'm just thinking about the males that I hear from, because I hear from, of course, males and females. But I get a lot of questions about what can I take, what can I take, what can I take. But as you point out, there's also a category of men who seem to not want to take anything, not want to measure anything, not want to take anything, but especially not take anything. And then there's the other group. And the other group somewhat surprisingly seemed to be the younger, excuse me, population,

Starting point is 01:27:19 who maybe grew up in the YouTube era or maybe in the era where sexual health was discussed more openly than it was certainly when I was in college. I mean, the extent of sexual health discussions at my high school, and I went to a very good high school were it only takes one sperm, which as you pointed out, is true for IVF, but more is better if you're trying to conceive naturally. And there were discussions about communication and consent, obviously, super important. And then they just kind of turned us loose to learn from our friends and other sources. I mean, and family sometimes had the discussion, sometimes didn't.

Starting point is 01:27:56 Different families, different discussions, obviously. So very little information. Nowadays, I think there's a lot more discussion about these things. And so the 20 to 40-year-old male crowd seems to be the crowd that are asking, yeah, what can I take? These are also the people who are getting on testosterone therapy early, perhaps without the need. I just want to flag that because I think, if I understand correctly, you're seeing a lot of testosterone therapy that perhaps people don't need. Is that right? Well, I think it's a mix. Some people probably do need it, but I think that, you know, before starting it, everybody should be aware of all the risks. And you've kind of highlighted some. But testosterone, any medication, right, is going to have some risks.

Starting point is 01:28:41 And so everybody needs to be aware of what those are. And for testosterone reproduction is certainly one of them. And if they're not already doing all the other things, getting adequate sleep, limiting their alcohol intake, not smoking, getting exercise, et cetera, seems that testosterone therapy would not be the primary entry point, like first work out all the. all the basics i think that's the big difference i think nowadays the what should i take question comes up early when people aren't necessarily doing all the other things um that they could do to promote their

Starting point is 01:29:08 health anyway this is observational on my part um you're the one who's clinic they're showing up uh too um i have a question about uti's urinary tract infections um in women pretty often um do men get uti's if they're getting more than one UTI per year, is that abnormal? Should men be examined for this bladder, urethra, prostate, penile architecture? I know there are ways that people can come in. I was reading about this prior to this episode that can ingest a dye, and then they can dye image the whole apparatus. Is that right?

Starting point is 01:29:49 That's true. Without having to cut anything, is that right? Is that worth people doing, or is that only under conditions where people are experiencing some vexing issue. Yeah, I think that some of those tests should only be done if there's a problem. But I think a male urinary tract infection is rare enough that it should be evaluated. So women have very short urethras, but men have a very long eryther. It has to go through the entire penile erythro, the prostateic urethra up into the bladder.

Starting point is 01:30:15 And so the way a urinary tract infection would happen, you know, one way would be that a bacteria actually gets all the way, you know, back. And that's just a much longer trek. And so if something rare like that does happen, we look for anatomic causes for that. So there can be different scar tissue in the urethor, for example. There can be stones in the bladder. There can be stones in the kidney. Sometimes men aren't emptying their bladders all the way.

Starting point is 01:30:38 So those men should be evaluated because there can be some pathology that we could hopefully identify and correct. Let's talk about erectile dysfunction. I put out the call for questions in anticipation of this episode. and no surprise, at least 30% of the questions from males were about erectile dysfunction. Or questions about what's normal in terms of libido level. Kind of interesting, right? And we'll deal with the first question first. But what are the most common causes erectile dysfunction?

Starting point is 01:31:15 Are they hormonal in nature? I think that's a common belief that if people are experiencing erectile dysfunction, erectile dysfunction that it's because their testosterone levels are too low. Hence, all the interest in testosterone therapy. Or are there other, say, blood flow related, pelvic floor related, neural brain to body neural connections that are responsible? I'm guessing it's all of these things. How do we parse this? And tell us about erectile dysfunction, what you most commonly see, what you most commonly do, in order to treat it. Yeah.

Starting point is 01:31:52 So, you know, erectile dysfunction, as you know, is sort of the inability to consistently achieve and maintain an erection. And it's fairly common. You know, of all the conditions I see, that's definitely the number one. So, you know, if you look at men over the age of 40, over half we'll have some trouble with erections.

Starting point is 01:32:09 Under age of 40 is probably about 15 to 20%. So this is a very common condition that we see. In terms of the etiology, it can vary a little bit. You know, we used to think that they were primarily psychogenic, but that was, years, that was decades ago. Now we know that most of them are organic. So it's actually a blood flow issue. So the most common conditions, just sort of nationally, would be the same things that cause blood flow problems anywhere in the body. So I have blood pressure, diabetes, you know,

Starting point is 01:32:34 atherosclerosis, anything that sort of can impair blood getting, you know, to the end organ. And sometimes, you know, there has been data that, you know, trouble with erections can actually predate other more, you know, serious, you know, vascular conditions. So the blood vessels and the penis, the penile arteries are about one millimeter, you know, and the heart and the brain, they're much larger. So, you know, it's much easier to occlude a small vessel than a large vessel. So that's why there have been some studies to support that it's sort of an early marker for vascular disease. So I think looking at those risk factors, you know, sort of lifestyle, obesity, again, is another, is a common one. Endocrine disorder is actually fairly small. It's probably less than 10%,

Starting point is 01:33:15 probably around 5% or so. Pelvic cancer treatment is another very common one after, you know, treatment for prostate cancer, whether it be radiotherapy or surgical therapy, bladder cancer, sometimes rectal colorectal cancer, that treatment also. Anytime we're, you know, involving some of the nerves and the vasculature and the pelvis, that can also impact erectile function as well. What about hernia? Hernia, that should be separate.

Starting point is 01:33:43 So sometimes if they're, you know, I always say that in medicine, you can never say never. But, you know, generally if that was going to manifest as erectile function, it would probably be due to maybe some pain symptoms can rarely happen during just the early postoperative period. But the blood supply, the nervous supply is separate. So you said something very important for people to hear. So I'm going to highlight it. You said that less than 10% of erectile dysfunction is due to a hormonal issue. I don't know how much time you're spending on YouTube and the internet, but that is going to be a shocker for a lot of males out there because so much of the discussion around testosterone is around libido and sexual function. So it's key for people to hear that.

Starting point is 01:34:29 It's also key for them to know about this other 90%. When you say blood flow issue, then what is the common first pass for treatment? And again, and forgive me for listing this off over and over, but we are assuming here that people have gotten their body weight down. They're sleeping enough. They're not ingesting excessive alcohol. They're not smoking or vaping. They're not smoking cannabis or doing the edibles,

Starting point is 01:34:55 although maybe we should talk about edibles and cannabis and endocrine effects. We'll do that later. Doing all the things right, avoiding doing the wrong things too often or at least completely. So we're assuming they're doing all that correctly. Their testosterone levels are somewhere in that, 300 to 900 nanogram per deciliter range. That's typical for the so-called reference range, at least in the U.S. I think it goes up to 1,200 or maybe 1,400 in other countries, but as other countries like to point out.

Starting point is 01:35:25 But it starts at two. No, I'm just kidding. But assuming they're doing everything correctly and it's not a testosterone issue, then if it's a blood flow issue, meaning they haven't had treatment for some pelvic cancer, what is the first line of treatment? Yeah, so assuming that lifestyle and all that has been optimized, medical treatment has been optimized, there's a lot that we can do. I always tell men, as long as you have a penis, we can always make it hard. So there's a tremendous amount. I'm sure that you're the most popular doctor in your field as a consequence.

Starting point is 01:35:58 Yeah, that usually does kind of ease everybody. So usually we start with oral therapy, so phosphatosterase inhibitor therapy. So that would be like seldenafil or Viagra, to Dalafil, Cialis, Avenifil Stendra, or Verdinifil libidra. Would you be wanting to talk about some of the specifics there? Are you, is the typical thing to put people on this 2.5 to 5 milligrams per day low dose or to give the higher doses that are more commonly used for erectile dysfunction per se? I think it depends, you know, why we're putting them on it and how much sex they have, too.

Starting point is 01:36:31 You know, on average people probably have sex, you know, partner sex maybe one. months a week on average, you know, when we're looking at men in their kind of 30s and beyond, you know, sometimes it can be a few more times a week than that. But, you know, if they're having sex every day or very often, that sometimes a daily dose can be useful, but generally, most men are on just on demand because they're going to fall into that, you know, maybe about, you know, a few times a month category. So that's usually where we start. And, you know, there is sort of a titration that can be done. You can go slightly, you know, higher doses or lower doses. So usually we start in the middle to the higher doses.

Starting point is 01:37:05 And, you know, we talk about some of the side effects they may have. But those probably help 60 to 70% of men. And they work well. You know, in terms of another common question is how do we decide which one we're going to start? Sometimes insurance will tell us which one we're going to do. That's a common one. You know, all these medications tend to be somewhat similar. One difference tends to be the time of onset, you know, how quickly they reach peak levels in the body.

Starting point is 01:37:28 And then also how quickly they're cleared from the body. So, Tidalphil is somewhat different, and then it lasts longer. The half-life is about 20 hours or so. So it's sort of marketed as a weekend pill. So some people like the idea of that, you know, taking a pill on Friday, so having some left on Saturday. But for others, you know, we start with one of the other ones. The fact that these drugs like Tidalphil also called Cialis, right? Is Cialis, the brand name?

Starting point is 01:37:55 Right. Okay. And Viagra is that a brand name? Right. stands for, what is the generic name? Oh, sylidinophil. So because they are effective in such a large percentage of cases, what does that say about the vascular system of all these males

Starting point is 01:38:11 that are having erectile dysfunction, but then it's getting resolved by these drug treatments? Is that, in other words, somebody comes into your clinic, they're having this issue, you prescribe one of these drugs, they come back and say, everything's working great, or maybe they don't come back, they just, you know, send an email, say everything's great. But do you need to have a discussion with that person about their overall vascular health?

Starting point is 01:38:36 Because a few minutes ago, you told us that the fact that they weren't getting erections due to what now appears to be a vascular issue can be resolved for the penile tissue. But is it going to solve their other vascular issues or should those people be on the lookout for cerebrovascular, cardiovascular disease that can potentially cause things at least as bad as erectile dysfunction or maybe. worse. Yeah, absolutely. Well, I think they should be screened. So, you know, sometimes I'm diagnosing in the first doctor that they're seeing in a long, long time. But otherwise, I do encourage them to see a primary care doctor to be screened for, you know, blood pressure, lipid levels, you know, fasting, blood glucose, all those things, again, sort of for early markers of some of these. Sometimes they're identified, sometimes not. But I think it's, you know, I think we kind of talked about sort of the ideal patient that's perfect body weight, nothing else

Starting point is 01:39:23 is going on. But that's, as you know, a very rare entity. So usually there's something that can be done to be optimized. And I don't, I try not to be alarmist about this, but I do want to, you know, encourage men to sort of take ownership of the health, because that sometimes can't improve, you know, some of these conditions. But again, we have terrific medications for, for men in whom we cannot. What are the common side effects of these drugs? So they're vasodilators. They open up blood vessels. So we get some off target effect. So headache, facial flushing, back aches, leg cramps, indigestion, nasal congestion. Those would be the most common. Before the last Super Bowl, There was some press about the fact that a lot of the players were taking these drugs at low dosages before the game,

Starting point is 01:40:03 presumably to increase blood flow to their muscles and brain. Is that what the rationale was? I think so. Yeah. You know, another is we talked about sort of how cycling may lead to erectile problems or sexual problems. There has been some data looking at taking like Biagra or one of these medications, the Alistadalphil, before a ride, again, to try and increase circulation to decrease the chance of any of the negative effects of prolonged saddle pressure. So it sounds like just increasing blood flow and lowering blood pressure slightly is just a good thing all around. Yeah, I think there's certainly a benefit. Yeah, because these medications were originally, I think, as you're alluding to, were developed as a blood pressure treatment. And this was sort of an amazing off-target effect that has turned into a billion dollar industry.

Starting point is 01:40:44 So you mentioned about 10% or less of erectile dysfunction is due to endocrine issues. Was it 60 to 70% can be resolved with these blood. flow enhancers. I know it's a terribly non-clinical, non-scientific way to describe the Viagra Sealis, Adelphal, et cetera. What about the remaining percentage and are there other treatments that you prescribed or given in which cases do you need to resort to, I guess, more invasive approaches? Yeah. So another therapy we have is erythal suppository, so you can actually put a medication and the tip of the penis is then absorbed by the rest of the penis. Also inject, it's suppository.

Starting point is 01:41:30 A suppository or a gel, or a jelly, yeah. So it's also a basidilator. Sort of the concept is very similar. Sometimes that, you know, is okay for men. And they tolerate it. It's safe for partners as well. It can tingle a little bit. So we definitely let men know because one of the main medications does cause like a little bit

Starting point is 01:41:50 of a burn as well. Why would somebody do this as opposed to taking the pill form of, the drugs we were just talking about. Mostly efficacy would be a big one. And so this can sometimes help where others cannot. So that's one. Penile injections are another common therapy. So the efficacy of penile injections

Starting point is 01:42:09 are probably 80 to 90 percent. Again, we're injecting basidilators into the penis. So the idea just opens up blood vessels easier to get and to keep erections. You can imagine there's a huge psychological barrier to putting a needle in your penis. Is this something that the patients are doing for themselves at home or that you're doing

Starting point is 01:42:25 Is it long lasting? Is that something you do with the clinic and then they come back every few weeks or so? No, yeah, this is an on-demand treatment. So we teach them how to do it the first time I do it with us in clinic. Ideally, we try and get an erection that lasts probably 20 or 30 minutes. So we usually start at a low dose. And then they just increase at home until they get, you know, an erection that lasts for that amount of time. Is it injected subcutaneous or actually into the, goodness, the meteor tissue of the penis? That's right, into the erectile bodies directly. Yeah, and they, you only have to inject one side. They do communicate with each other.

Starting point is 01:43:00 Most of them say it's fine. It's a small, it's a very small gauge needle, about as big as, you know, a few strains of hair. I have an appointment over in ophthalmology, and I've seen injections into the human eyeball, and it is incredible how fast and how painless that procedure is when it's done by the right person. Nobody should try that at home on their own. But when it's done by a skilled ophthalmologist, it's just striking. You know, you think about needle in the eye, you know, what's worse? It's like the childhood rhyme, right?

Starting point is 01:43:24 stick a needle in my eyes. I can't think of anything worse. But maybe, you know, an injection in the penis sounds almost as bad. But you're telling me that if patients are prescribed this, that they can do this with limited, if any, discomfort. Well, it does have a high dropout rate. Surprise, surprise. Yeah, I think no one's excited about it. You know, it's, I guess the mood can sometimes be affected. But a lot of couples are very comfortable with it. Again, it's very efficacious. The man can do it. His partner can do it. So it does work well. And I guess here we're sort of ascending the list of invasiveness. Right.

Starting point is 01:44:00 What is at the sort of top tier of invasiveness for erectile dysfunction? So then we go into penile implants. So there's actually a surgical procedure we can do to put a device inside the penis that can help men be hard when they want to. And that comes in sort of two main forms. There's either non-inflatable or inflatable. So the non-inflatable is sort of a bendable. It has sort of a metal core. and so when men don't want to have sex, they bend it down.

Starting point is 01:44:27 When they're ready for sex, they can kind of bend it up. It's really just there on demand. Yes. Yeah. Interesting. Yeah. So it's very simple to use. Sort of the more, I guess, kind of natural form would be the inflatable.

Starting point is 01:44:40 So when you're not using it, it's deflated. And then when you're ready to use it, it's inflated. And you inflate it with basically a pump that's in the scrotum. So all this is sort of surgically implanted inside a man all under the skin. You know, unless you know what you're looking for, it'd be very done. difficult to tell if a man has it or doesn't have it. But when he's ready, he pumps it up and it moves fluid from a reservoir, which usually is also surgically implanted into the penis to get a rigid erection.

Starting point is 01:45:06 What is the relationship between psychological arousal and erection as it relates to these technologies? I mean, the way you're describing it sounds purely mechanical, right? We're talking about nocturnal erections, which I suppose people could be having erotic dreams, but I don't think that's a prerequisite for nocturnal erections at all, right? So is the idea that if adequate blood flow is achieved, then any signal from the brain can initiate a cascade of blood flow that creates the erection? Or is it the case with some of these treatments that sounds like blood flow is almost autonomous?

Starting point is 01:45:45 Right. Well, I think a lot of these, yeah, the blood flow is not adequate, And that's why we're having to, you know, sort of go beyond. But generally, as you point out, there's different stimulation, whether it be, you know, visual, tactile, or factory that sort of starts that cascade that releases neurotransmitters in the penis that leads to this vasodilation, you know, naturally and men get erections. A few years ago, I was reading about vasopressin inhalants. You know, there was a bunch of stuff hitting the market. By the way, I don't suggest that people get experimental with this stuff. You know, as a neuroscientist who also knows the thing about neuropeptides and neurohormones that

Starting point is 01:46:22 can impact the hypothalamus, you know, I just cover my eyes and kind of cringe when I think about people inhaling vasopressin thinking, oh, yeah, you know, there's a study that vasopressin increases sexual desire or something like that. But nowadays I'm reading a lot more about a really interesting peptide treatment, which I think is a FDA-approved prescription drug, which is relates to a melanocyte stimulating hormone that comes out of the medial pituitary that is used to increase sexual desire. It's prescribed for women, but men are starting to take it. And it seems to have, at least from what you read on the internet, a pretty profound impact

Starting point is 01:47:05 on libido and on erectile frequency and persistence. Is this something that you know, you're using in your clinic? Yeah, what about these peptides that people are inhaling and injecting? And some of them are taking an oral form, but most often I think it's nasal inhalant or it's a subcutaneous injection. Yeah, so those are not ones that we use in clinic. But I think, you know, looking at sort of just sexual dysfunction broadly, there are a lot of things that, you know, we do try and help.

Starting point is 01:47:40 And one of the things sort of that kind of relates to that, that is it's, been a proposed treatment for it is this concept of delayed orgasm or delayed ejaculation. So I think everybody's familiar with premature ejaculation, right, where men ejaculate too quickly. But on the other end of the spectrum, there's men that takes, you know, a long time to ejaculate. And, you know, what that is is sort of defined differently. But generally, most people would say, like, sort of two standard deviations above the average.

Starting point is 01:48:06 So on average, probably around five minutes or so, two standard deviations would be kind of 20 to 25 minutes. So for men that take that long to ejaculate, that would be considered delayed, or sometimes they don't ejaculate every time that they, you know, have relations. So for those, I think there is a need for treatment because there's no FDA-approved therapy for that. And so that's why I think, you know, providers are trying some of these other, you know, more experimental things. There's some that we use, just not that one in particular. There's also some devices that have been trialed as well. But it's a challenge because, you know, I certainly really feel for these men. And it's one of the pleasures in life.

Starting point is 01:48:41 And some of them are never able to have sex or only, or sorry, never able to orgasm. And some are only able to do it very rarely. So we do want to offer them benefit. What about pelvic floor health more generally? The topic of pelvic floor health is something that comes up more often around female reproductive health and urology. You hear about kegels, kegels, kegels, I don't know. I guess we'll have to ask him because it turns out, Kegel was a person who named the exercise after himself.

Starting point is 01:49:15 Whether or not he did them or not, I do not know. But my understanding is that Kegels are a pelvic floor strengthening exercise. And my understanding is that some people experience urinary or sexual dysfunction because of a overly relaxed, aka weak pelvic floor, but that some people have the exact same problems. because of a hyper-contracted, aka overly tense, tight, strong pelvic floor, meaning don't run out and start doing kegles

Starting point is 01:49:47 just because you heard about them. They're not good for everybody. They might be bad for certain people. But what about pelvic floor health? I mean, should men be paying attention to pelvic floor health? Should men be doing pelvic floor exercises? I mean, I think it's really key that you say that because, you know, not everything you hear about is good.

Starting point is 01:50:01 And I think it's not good for the right person. So there are certainly men that I see that have very, you know, just a lot of tension, and a lot of anxiety. Sometimes these men, you know, urinate every hour. I mean, there's other things and you can just tell they're just sort of very wound up. And I think for that man, you know, one of the issues you kind of allude to is he probably needs to relax more. So, you know, pelvic floor physical therapy can still benefit you because there are some just different feedback exercises that could be done to help with relaxation. So, you know, in the eurrologist's

Starting point is 01:50:28 office, there's usually a list a lot of different providers around the region that can help with some of these. Kegel exercises, though, can be useful, you know, for example, for, like, prostate cancer rehabilitation, some of these men, where we're trying to kind of rebuild some of the strength or maintain or improve continents in these men. We do want to strengthen some of these muscles so that they can sort of recreate or replace what was lost when the prostate was removed. So I think for the right man, they can be useful, but, yeah, it could be a dangerous tool in the wrong hands. And you mentioned that if people want to learn more about pelvic floor therapy, they can

Starting point is 01:51:02 contact their local urologist and find a good pelvic floor. good male pelvic floor specialist. Do they tend to specialize male, female? They're usually pretty much gender or sex agnostic, so they usually are able to help all. And forgive me for asking for an abridged anatomy lesson here, but could you describe the pelvic floor muscles and how they relate to the bladder prostate urethropenus anatomy

Starting point is 01:51:30 that you talked about before? because I have the picture of the bladder urethroprosate penis in my brain. I know my life experience where the testes and scrotum are relative to all of that, but now I'm trying to figure out how, like so the pelvic floor, a bunch of muscles that are attached to the pelvis, but how do they interact with those organs? Yeah, it's a good question. So they sit beneath, you know, the sort of in the perineum,

Starting point is 01:51:58 so the area between the scrotum and the anus and back beyond. too. So they basically support all the structures there. They support, you know, the base of the penis, the prostates, the bladder, the rectum. And, you know, they're, they kind of keep main, you know, adequate tension to keep all those structures up. They relax when, you know, different functions are necessary. They're very important for ejaculation. You know, some people think that they kind of trigger some of the orgasmic response as well. You know, sometimes men will have, you know, pain in that area, in the perineal area can transmit to other parts of the body like the scrotum. You know, one of the one cause of scrotal pain, and there can be many,

Starting point is 01:52:35 can sometimes be pelvic floor dysfunction. So I think, you know, again, pelvic floor therapy can be useful for sort of a constellation of symptoms, again, some urinary symptoms as well. So I think for some patients, it can be helpful. But, you know, again, if you get things too tense, that can sometimes be harmful. So presumably these pelvic floor therapists also help people achieve a more relaxed pelvic floor if that's what they need. Exactly.

Starting point is 01:53:00 Got it. Going to some of the questions that came back to me when I solicited for questions and anticipation of this episode, several, not a few. Let's say a couple dozen people asked about split urine stream. Is that a signature of prostate overgrowth? Is that a urethral issue? Is it perfectly normal? I'm assuming here they mean a split stream.

Starting point is 01:53:28 of urine that doesn't unify at any point. They're talking about a consistently split urine stream. And for those of you, they don't know what I'm talking about, we're talking about a urine stream that's actually two urine streams. And we're assuming one urethral opening, because I hit the literature on this. And there is a case of failure to fully fuse the urethral duct during development where some, I'm assuming small fraction of males

Starting point is 01:53:52 have a urethral opening on the base of the penis and at the tip of the penis. Let's rule that out as a possibility. for now. But now that it's on the table, what percentage of males have that two urethral openings? So, well, hypospatias, which you're describing, where the actual meatus is not at the tip, but it's kind of along the proximal urethra, or, you know, even further down, sometimes in the scrotum, probably about 1% of births. And usually it's recognized at birth, and oftentimes it's surgically corrected because it's better to repair it early rather than later.

Starting point is 01:54:25 Okay. So ruling that out. What is the cause of split urine stream and is it a signature of a larger issue? You know, one of the reasons that we, you know, urinate sort of from an evolutionary standpoint, right, is to, you know, basically deposit sort of a convenient time our waste. And we don't want to get it everywhere because we don't want to sort of label ourselves with the smell of urine because that will be easier for predators to be able to identify. So just similar to today, we'd like everything to get in the toilet without creating a mess. So anytime there's turbulent flow, it certainly could signal an issue.

Starting point is 01:55:02 So it could be like an erythral issues or pointing out a prosthetic issue, inadequate speed, you know, of getting urine alpamia. So you definitely should see a physician to get evaluated because there's likely some issue that can be improved. The most popular question I received from males, however, was about perhaps no surprise, penis length. You're an expert in this, actually. Not just because you're a urologist, male reproductive health expert, but you published a study recently on the changing trends in penile length. Tell us about that study. I have so many questions about the methodology, because I have to assume this didn't involve self-report, right?

Starting point is 01:55:53 Those were excluded, yeah. Yeah, so lying was excluded. Being facetious here. But yeah, how was this study done? I mean, pretty incredible study. And the results are, I don't know if they're surprising or not. First, I thought, oh, this is surprising. But the results were only surprising in light of what you were talking about earlier about sperm and testosterone levels.

Starting point is 01:56:16 I think I'll let you describe the study now rather than giving people the punchline here. Yeah. So, I mean, the origin was that we were looking at. We wanted to know average lengths for another project that we were doing. And going down the rabbit hole, this has been reported for decades. There's different reasons that people have reported penal length. Sometimes they do it just on volunteers, again, to sort of get the average lengths of different populations. Sometimes it's done pre and prosergicly to try and understand what changes would occur.

Starting point is 01:56:45 So we just sort of called the literature, found data on 55,000 men all over the world. And wanted to see if there was a, you know, sort of a time pattern with that. And similar to your hypothesis, we assume based on all the other data that we would likely see a decline, you know, whether it be, you know, chemical environmental exposure. But if nothing else, if we're getting bigger, you know, the functional peanut length should decline because, you know, the super pubic fat pad will get a little bit bigger. And so we'll kind of lose peanut length with that. And so much to our surprise. The superpobic fat, excuse me, being the pad of fat directly over the penis. Right. Right.

Starting point is 01:57:20 And so, you know, if that gets bigger, that'll necessarily compromise penile length. But, you know, as you alluded to, what we found is actually the opposite, that the penises were getting longer with time. So how it's measured differently. So one of our inclusion criteria was that all the studies had, have measured sort of in an office, sort of in a clinical setting. So whether it be a, you know, a clinician or whether it be a researcher that actually did it. So there's different ways you can measure a penis.

Starting point is 01:57:46 You could just do a stretch length. So you kind of stretch it up as much as you can and then use, sort of a ruler to measure how long it is again from as deep as you can get you know the pubic bone ideally up to the tip of the the glands or the okay so here's what he's describing he's talking about measuring from the top not from the bottom believe it not people ask questions about this measuring from the top not from the bottom no cheating um you're talking about stretching the penis while it's flaccid presumably and then measuring from essentially contact with a location that's contact with the pubic bone to the the tip right okay

Starting point is 01:58:20 Okay. So that length was recorded in 50,000 men? Wow. Yeah. So that was one. And then we also looked at erect length. And so there's different ways that an erection can be achieved sort of in a clinical setting. So one is you could ask a man to stimulate himself and then measure. So that was some of the studies.

Starting point is 01:58:37 And then the other method, so we have alluded to earlier, as you could inject a man with the medicine to give him an erection and then measure it. And did 50,000 men participate in that aspect of the study? It was less. No, that was, I think that was about. probably 10 to 15,000 men. I have to wonder whether or not it's easy or difficult for people to recruit subjects for these studies. I don't know. I could see it going both ways.

Starting point is 01:59:00 Yeah, some of the studies actually had a tremendous number, had about like 15,000 men. Some individual studies contributed that. And actually interesting, after we published it, there were some men that volunteered for the next study to be measured. I'm sure you'll hear from some of them after this episode. What was the major finding? So the major finding we wanted to do is just

Starting point is 01:59:20 of normative data. We found that it varied around the world. So based on different regions, the average length, you know, varied a little bit. But generally, on average, a rec penis is probably between about five to six inches somewhere in that neighborhood. So that was kind of the take home. That was the average. The average for wreck length. Did you publish the full distributions? We didn't. I think we were, we're, we're, we're, our plan was actually to make a follow on study. So we could show everybody, you know, I guess probably they were interested where they kind of fell on the graph. But it was fairly, you know, it was normally distributed.

Starting point is 01:59:52 Yeah, I would think that despite the, you know, the wide availability of pornography that the distributions, like the scatter plots of all the data, would be interesting to men. For the same reason that the testosterone by function of age data published as a scatter plot in that textbook I referred to earlier. Right. Very interesting because the scatter plot distribution. distributions, I feel like, point to other takeaways that one can be in their 70s and have testosterone levels equivalent to a male and healthy male in his 30s. That one can be in their 30s and have testosterone levels that are twice as much or half as much as age match cohort, this kind of thing.

Starting point is 02:00:39 I think there's value in that. So what other takeaways arrived with the data from the penis length study that perhaps we didn't, we didn't hear about? What did you find most interesting about the data? Well, that there was any change over time. You know, this was a fairly short study. It was probably about 30 years or so. But we did find that penile length has been increasing over time. So, you know, that was just sort of fascinating,

Starting point is 02:01:05 that we would see sort of in such a short interval of time, that there would be a change number one, but that we would see a lengthening number two. So, you know, again, similar to the concerns that arose for these, you know, relatively short period of time where you would see changes in semen quality, you know, it suggests something sinister, right? It's unlikely to be a genetic change because that would take, you know, centuries probably,

Starting point is 02:01:27 certainly several generations. So the fact that this happened so quickly was just surprising. This brings to mind some of work that I was involved in years ago. When I was a master's student, I studied early organizing effects of hormones on the brain and body. And I'm sure this has been updated since then. But my recollection is that during embryonic development, males are exposed to a certain amount of dihydro-testosterone, not testosterone, but dihydro-testosterone, which organizes the brain male, as they used to say. Now the verbiage around that would probably be a little bit different. But the idea is that males are born with penile tissue, of course, but then it's during.

Starting point is 02:02:18 puberty that the same hormone, dihydro-testosterone, then exerts an activating effects on the genitals, and the genitals grow during puberty, penis length increases. So assuming that the study that you did was on males post-puberty, I'm assuming it was, then it would imply that something's changing about the levels or the signaling related to dihydro-testosterone. How could that happen? Do we have any ideas about what might be happening? I mean, this is the opposite of environmental endocrine disruptors, preventing sperm from being as high quality and numerous as they could be or from, you know, or environmental factors, either in utero or post-utero, suppressing testosterone levels.

Starting point is 02:03:04 Here we're talking about the opposite effect. We're talking about dihydro testosterone levels, presumably being higher in males over the last 30 years and thereby longer penises. Right. So, I mean, I think there's different conjectures that you can make about why this could happen. I mean, it could be, you know, maybe endocrine disrupting chemicals, you know, in utero, some early exposure, you know, that some of the mothers had to kind of androgenic effects during the male programming window that may have led to some longer lengths.

Starting point is 02:03:30 Another hypothesis we had is that if males are going through puberty earlier, the earlier one goes through puberty, the longer length tends to be. So maybe that provides sort of this link. So earlier puberty tends to be longer, potentially means longer duration exposure to dihydro testosterone, longer penises. Right. Yeah. You may be surprised to know you might not be surprised to know that there is a subculture

Starting point is 02:03:57 online. I know because they contacted me in anticipation of this episode of post-puberital males who take a combination of dihydro testosterone and low levels of growth hormone in efforts to try and increase their penile length. And the ones taking dihydro testosterone, they're not taking pure DHD, they're taking things like oxandrolone, which very closely mimics the structure of DHD. They report some success. Fortunately, they did not send me pictures. Otherwise, it would have just forwarded them to you for your next study.

Starting point is 02:04:37 But this stuff is happening in post-peopritoral males. So it all rests on this dihydro testosterone hypothesis. just a point of interest. Yeah, I don't know. It just physiologically, it doesn't make sense why that would work as you're pointing out post-pevertilly. And then unless they're doing other things, you know, some sort of stretching exercises or I think called jelking. But yeah, I would not recommend that. Thank you.

Starting point is 02:05:03 That was the response I was looking for. So that community will be listening with open ears. Don't do it. As long as we're talking about D.H.T. Dehydro testosterone. it's only fair to discuss the drugs that many people take to suppress dihydro testosterone in hopes to keep or grow their hair. Things like fanasteride, dutasteride.

Starting point is 02:05:29 Some, maybe many, not all people who take these drugs, particularly in oral form, experience sexual dysfunction issues and other issues related to suppressing D.H.T. That said, my understanding is that these drugs, are also quite useful, maybe even life-saving in some cases, for staving off certain forms of prostate cancer. What are your thoughts about finasteride detastriide? Do you see people coming into your clinic who are having sexual dysfunction or other types of issues

Starting point is 02:06:02 because of their hair or attempt to maintain or grow their hair issues? And equally important is that we talk about so-called post-finasteride syndrome. I got a lot of questions about post-finasteride syndrome. Because I'll describe it in a couple of minutes. It sounds pretty devastating for these people's lives. And I'll explain why it's so devastating for them in a moment. But what about finasteride-utastride and these drugs that are effectively DHD blockers?

Starting point is 02:06:33 DHT levels if they get too high, indeed can miniaturize the hair follicle, cause people lose their hair typically up front or in the back, so-called crown or whatever, you know, Widows peak or everywhere in some cases. It also induces hair growth on the back, beard growth as we understand. But then people go in and take these drugs to try and maintain or grow their hair, and oftentimes they have erectile dysfunction or other issues. Is that surprising to you? You know, I think the men that we see these side effects tend to be, you know, younger men in their 20s, 30s and 40s.

Starting point is 02:07:07 And they take it, as you're pointing out for hair loss. So before it was FDA approved for that indication, at least phenasteride was, you know, they did randomized control trials to look. And one of the other things that we'll talk about, too, is just reproductive effect. So they did, you know, lots of studies to see if there were changes in semen quality, you know, for men on finasteride versus the placebo. And there were some very subtle changes. But, you know, sort of in post-marketing, now we see these patients in clinic, you know,

Starting point is 02:07:34 everybody to enroll in these studies had normal functions. So I think that's sort of important to understand. And obviously, that's not life, right? That people come in with sort of different baselines and different amounts of results. And so we now know that there's probably people that are a lot more sensitive to these medications than others. And so there are some men that drop their sperm counts dramatically. And usually if we stop these medications, their sperm counts can recover. And usually a spermatogenic cycle is probably about two to three months.

Starting point is 02:07:59 So usually in maybe three to six months, we usually see recovery for most men. But similarly for, you know, sexual function. I certainly, you know, have a number of patients, you know, that do complain of low libido erectile function this post-binasteride syndrome. You know, and the mechanisms, I think, are less certain because, you know, measuring testosterone levels, which we do, you know, sometimes if androgens are low, or even if androgens seem to be in the maybe normal range or low normal range, we'll try and increase testosterone through a variety of means, testosterone, clomophine sometimes we'll give. You know, it helps some men, but not all. So I think the exact mechanism of what is going on here,

Starting point is 02:08:35 what is changing. I think, you know, we need more, you know, more understanding about the exact sort of path of physiology, you know, or neurochemically. It seems like a pretty serious tradeoff to either maintain to grow hair or lose sexual function. I mean, I talked about DHT and some of these side effects of finasteride deastoride on previous episodes. And, you know, I'm not a clinician, but my encouragement is always for people to approach these drugs with a real level of seriousness, if not caution. The post-finasteride syndrome was described in these online questions as seemingly permanent, even though people had ceased to take finasteride or deastoride.

Starting point is 02:09:22 So, in other words, they were taking this stuff. I don't know how they felt while they were on it, but they stopped taking it, and the sexual dysfunction issues don't seem to be resolving. Does that mean they should go see you or another male urologist reproductive health specialist? Yeah, I mean, oftentimes they do. for, you know, these complaints. You know, they start to notice that when they're on the medication, then when they, you know, usually through online research, kind of learn about this potential entity. Sometimes they discontinue. Now, some men do have resolution when they stop, but there is

Starting point is 02:09:53 this permanence in some handful of men, you know, they've done, you know, MRI imaging to try and understand sort of, you know, more anatomically or functionally what exactly is going on. I think there's still a lot of unknowns about it, but it can be, you know, permanent for some. So they come in, you know, when they see me in clinic erect all this function, low libido, and then we go down all the host of treatments that we talked about and the evaluations that we talked about. Again, we have resolution in some, but there are some that seem treatment refractory. Yikes, that's my only response. I mean, permanent effects on sexual health as a consequence of an attempt to maintain one's hair.

Starting point is 02:10:30 I mean, this is where, you know, in all seriousness, it just sounds like something that people need to think very seriously about because as I understand there's nothing that can predict whether or not someone will have post-finasteride syndrome. Right. And I did a bit of reading on this within the scientific journals as well. There isn't a lot of information, as you point out, because it's a fairly recent phenomenon. And that highlights a different issue. This may be the first time in history where young males are taking finasteride and deastoride.

Starting point is 02:11:04 And that might be the cause of the post-finasteride syndrome. I think you alluded to this earlier. These drugs have proven to be very beneficial for older men treating prostate issues. Exactly. Yeah. Right. So this is a post-finasteride syndrome, I think, falls under the category of medical conditions that, you know, a few years ago we would hear the same about chronic fatigue syndrome. Even fibromyalgia not long ago was considered one of these.

Starting point is 02:11:32 oh, is it all a psychosomatic issue? Now, we now clearly know that's not the case for fibromyalgia, by the way. But I can recall a time not that long ago when people in the medical profession kind of like, well, yeah, I don't know if this is a real thing. But post-Franasteride syndrome sounds certainly real for the people that are suffering from it. Exactly. Yeah. Okay. Well, the reason I'm spending so much time on this is that I get a lot of questions about it.

Starting point is 02:11:56 And there are clearly a lot of young males who take finasteride or do tasteride or are thinking of doing that for cosmetic reasons. And I think they should be aware of the potentially serious consequences. Yeah, agree. Yeah. But you did say earlier that if someone has a penis,

Starting point is 02:12:12 you can get it hard. So all is not lost even for these post-finasteride syndrome. That's true. Good. Okay, we'll hold you to that. You mentioned clomophene. Could you explain what chlomaphene is

Starting point is 02:12:26 and what it's used for? Because, again, we want this discussion to be centered around the real science, the real medicine. But there is a growing kind of sub-community of people out there who are saying, okay, testosterone therapy can cause us these sperm suppressive issues and perhaps some other issues. But doing nothing might not be an option for somebody who wants to increase their, whatever, libido, other aspects of androgen function. And so there are a growing number of people.

Starting point is 02:13:00 out there who are taking clomophine only in order to presumably increase testosterone, but my understanding is that it would impact the estrogen pathway as well. Yeah. What's clomophine? What are your thoughts about people using clomophine sort of off-label simply to increase androgens? It's sketchy to me for reasons related to changes in neural circuits. But you'll tell us how it works. Yeah. Well, thank you for including the off-label disclosure. Anytime I talk about this, I always have to say. say that. But so clomophine is a selective estrogen receptor modulator. So basically it blocks estrogen. And so from our earlier discussions of how the pituitary works, you know, there's sort of

Starting point is 02:13:40 an elaborate feedback loop between the pituitary and the gonads and the man the testes. And so what happens is, you know, FSH LHC's gonadotropin stimulate the testicle to make sperm and testosterone. Testosterone's peripherally converted to estrogen and that feeds back on the hypothalamus to stop that. So again, you don't get an overproduction. So by blocking the. estrogen receptor at the level of the pituitary or the hypothalamus, you'll stop that. And so the idea behind blocking that is that you'll get more production of FSAH LH, more of these drivers, so you get more testosterone. You get higher stimulation of the testicle.

Starting point is 02:14:15 You know, the hope is that for fertility that sometimes it can improve sperm production too, and there's some limited data that can help. But I think as you're alluding to, it's sort of a way to just augment your body's own production of testosterone. So it certainly does that. I think there's no question that testosterone levels do. rise. I think that the reason that doesn't always help is because not every problem is solved by testosterone. We kind of talked about someone in this discussion, but also that you know, you do need

Starting point is 02:14:40 some estrogenic signaling as well. And so by blocking that, you know, even partially, because there's also some partial agonist effects of clomophene as well. It may limit it. And, you know, it turns out that estrogen signaling is important for a lot of things. It's important for, you know, bone health, but sexual health, too. It's important for libido. So that may be partially. blunting some of the hope for benefits of testosterone. I found that men tend to be happier on testosterone than some of these other forms, and that could be a possible explanation. But one of the advantage of chlomophene, if we are thinking about this, is a treatment for low testosterone and hypergonadism, is that it doesn't have the same toxic effects on sperm

Starting point is 02:15:17 production. So by maintaining the body's own production of testosterone, by maintaining production of FSAH-LH, will continue to get sperm production. So for this reproductive age man that has low testosterone and symptomatic low testosterone, you know, low energy level, sex drive, mood, sleep problems, can be a worthwhile treatment. And it does help a lot of men, but not everybody. I've always been curious why if the goal is to increase sperm production, that the most common treatment is HCG, human corionic, gonadotropin. Because as you mentioned earlier, lutonizing hormone and FSA, follicle stimulating hormone, are deployed from the pituitary and travel to the testes where they stimulate testosterone production and

Starting point is 02:16:06 sperm production, but it's the FSAH specifically that encourages sperm production. So why wouldn't a man who's taking maybe testosterone therapy or who perhaps just wants increased sperm count and quality take FSAH instead of human korean? and get atopin, which is more or less a proxy for leutonizing hormone. That's a really good question. And so what FSAH does, like you said, is it stimulates sperm production. So it seems like it'd be a much more logical treatment. And actually, in randomized placebo-controlled trials, it does do that. So one of the reasons, it does do that. It does help. Okay. So it's beneficial. And we should, we should give it more. But one of the reasons that

Starting point is 02:16:44 we don't is cost. So it's rarely covered by insurance. And HCG, a month of that is in $100. So let's say like $3 to $500. But a month of sort of therapeutic FSA is probably two to three thousand dollars. So that cost is really limiting. It takes two to three months to make a sperm. So, you know, men often have to be, would have to be on it for several months. But there is reasonable data that would help. And it does make, you know, a lot more sense that that should be given is adjuvant therapy with testosterone rather than HCG. But HDD does work, you know, sort of everyone's surprised. It does actually help. But yeah, I agree. There is sort of a contradiction there. So if the price came down, it doesn't,

Starting point is 02:17:21 you know, this is another off-label medication for that indication. It would be, it could be worthwhile. One hormone that we haven't discussed is prolactin. I'm familiar with prolactin from a variety of perspectives, but I always think of dopamine and prolactin as kind of a seesaw relationship. Dopamine's up, prolactin is down. You know, dopamine is elevated with sexual desire, sexual activity, post-ejaculation, prolactin goes up, sets perhaps the refractory period on erection for some period of time, and then dopamine comes back up, but, you know, this kind of thing. And I realize that's far too simplistic, that prolactin is doing many things in the brain and body besides that. But how often do you see hyperprolactinemia's, I don't know if plural prolemia's

Starting point is 02:18:08 is clinically correct, but elevated levels of prolactin that are causing problems for men? What are some of the telltale signs of that? And this, I'd like to you. use as a segue to talking about some of the sexual dysfunction that is commonly discussed around the use of SSRIs and other drugs to treat depression and mental health issues that sometimes create endocrine and or sexual health issues. Yeah, so prolactin is sometimes, it's a diagnosis, hyperphylactinemia, it's a diagnosis, make not that many times. I would say, you know, less than 1% of the patients that we see will end up having that. But usually it's a handful of times a year, you know, we see a lot of patients. Typically, the telltale sort of symptoms would be, you know,

Starting point is 02:18:57 ones of low testosterone. That's a common one. But, you know, in my practice, I see it a lot with known with very low sperm production. So I've diagnosed several prolactin secreting tumors. And the manifestation of that was, you know, they weren't getting pregnant. We checked a sperm count was very low. You know, that mandates a check of testosterone, which is also very low. And then that leads to a prolactin, which is very high. And then that was diagnosed. So it's something I think, to be aware of, but I don't know that there's not usually a lot of symptoms and sort of going to a clinician when you're having sexual dysfunction, symptoms of low testosterone or fertility problems will usually, you know, be able to diagnose if it's present.

Starting point is 02:19:35 Are there any other hormones in the galaxy of sexual health-related hormones that fall into, you know, common clinical practice for you? I check estrogen as well. So I think that's another one. Again, because of the relationship with obesity, I think that can be important. Sometimes there's too much aromatization. And so sometimes that can be a problem. I think just like we talked about normal, estrogen signaling is important.

Starting point is 02:20:03 I think too much can be bad. So there are some men where reduce the manifestations that it can manifest as gynaecamastia in some cases. Male breast tissue. Mill breast tissue, yeah. As I was told, what was it, that the male breast tissue is sort of like the appendix. It's there, but it's not very interesting. Right, right, yeah. Everybody has them, and we just don't want the growth to get out of control. Could you tell us about one of the world's most difficult to pronounce words, which is vericacil?

Starting point is 02:20:31 Yes, so varicoseil, it's a very common condition, probably about 15% of all men have it, and it's a very common cause of infertility. If you look at all the etiologies, it can be 30 to 40%. So basically what it is is dilated veins in the scrotum. So obviously we need veins to get blood out of the testicles. But sometimes they can be a little larger than average, and there's sort of a little bit. normal for thermal regulation. So if the veins get too big, it's thought to warm up the testicle. The other thought is that it doesn't adequately clear some of the metabolites. So exactly the path of physiology is somewhat debated, but I think those probably contribute. And it's something that everybody should be evaluated for if you're concerned about fertility. So again, we see it very

Starting point is 02:21:10 commonly. You know, given the fact that a lot of men have it, about one and seven men have it, it doesn't always cause a problem, but maybe about 20 to 25 percent of the time it does. So mental manifests with low sperm counts we see sometimes discomfort you know ache you know worse at the end of the day than at the beginning worse of the activity anytime blood can pool sometimes it stretches and some men feel that and then in kids sometimes it can lead to either stunted testicular growth or shrinkage of the testicle it's also thought to be a progressive lesion so the longer man has it the more damage it can do it usually manifests around puberty in general so it's not a concern for everybody but I think certainly if couples are having difficult to conceiving, you're having discomfort in the area,

Starting point is 02:21:50 and you have one, it's a discussion you should have. What about Paironi's disease? Yes, so Paironies is a scarring of the penis, which leads to curvature or deformity. So the way erections work is everything swells. And you can imagine if there's a scar tissue, it doesn't swell symmetrically. So you'll get like a curvature deviation. Sometimes you can get an hourglass or sort of a banding. If you look it up on the internet, you can see a host of different deformities that men get.

Starting point is 02:22:15 probably present about 5, 10% of men, so it's very common. Sometimes it could be from injury, you know, from, you know, like a penile fracture or other, you know, sort of less severe form of injury to the penis. Sometimes men have described hitting it on different things. Potentially that could lead to it. Sometimes it can manifest after prostate cancer surgery or other kind of surgeries, which can, you know, sort of stun the penis or, you know, injure some of the nerves of the penis. So that's another condition we see commonly. You know, obviously it can lead to bother, you know, and erections are not straight. That can just, you know, cause, you know, psychological bother to men.

Starting point is 02:22:56 It can also physically make it difficult for a man to have sex. You know, sometimes it can limit certain positions. So that's another common complaint we see. I think it's something that men should be aware of. There's now awareness campaigns now that there's an FDA approved medicine for it, collagenase or zyiflex, which is a medicine that's all scar tissue. So that's one of the treatments we have for it. There's also different devices, sort of stretching devices where we try and just mechanically

Starting point is 02:23:22 remodel the penis to allow it to be a little bit straighter. And then there's also surgical options too. So there's a lot we can do. I always tell men, again, as long as you have a penis, we can make it hard, but we can also make it straight. I'm wondering why in the study about penis length, testicular size and volume wasn't also measured. And that's something that we haven't discussed. What is the relationship between testicular size and volume and some of the other parameters we've been talking about?

Starting point is 02:23:53 And maybe this is also a good time to highlight any kind of morphological signals that would warrant people coming to the clinic. So asymmetry in testicle size, for instance, changes in testicular size. obviously a pea-size lump they taught us in high school is a warning sign of potential testicular tumor or cancer. You know, we didn't really talk about testicles. Yeah, so I think that, yeah, kind of being aware, you know, the average size of a testicle for a man is about, you know, it's sort of about a walnut. So it's about 16 to 20 cc's.

Starting point is 02:24:33 Usually if you're going to measure it, it'd be about four to four and a half centimeters and longest axis to give, you know, your listeners or viewers at some idea. If it changes, certainly let people know. If you feel anything, let people know, although our, you know, national guidelines on screening practices recommends against regular testicular self-exams, interestingly, because I think the concern is that it leads to more anxiety than cancers that it would diagnose. But I think, you know, I always tell men, no one knows your scrotum better than you. So if you identify, you know, a problem, you should bring it to attention. So, you know, the classic appearance or the, you know,

Starting point is 02:25:09 way that a testis cancer would manifest is a firm painless mass that you kind of feel coming from the testicle. I find it interesting that at least as I understand women are encouraged to do regular self-exams of their breasts for for lumps. But you're telling me that men are actually discouraged from doing regular exams of their testicles for lumps that could be cancer. That feels like a unfair asymmetry. It does. I mean cancer, I mean both both seem very much. important. Oh, yeah. Well, I think there's no question, obviously. I'm very biased. Yeah, yeah. I was trying to say it so you didn't have to, right? Oh, yeah. I don't want to get in trouble with the U.S. Preventative Services Task Force. I mean, I don't want anyone to get cancer. I mean, so I don't even

Starting point is 02:25:51 want a dog to get cancer. So I'm surprised that they discourage self-exam. But is it because men are getting it wrong? They're coming into the clinic thinking they have testicular cancer, and then most of the time they don't. I think that's the concern that, you know, the number of cancers that are diagnosed versus the false, you know, the false, you know, lumps that they identify just lead to more anxiety and end up not actually, you know, causing more harm than good. I think is the concern. But yeah, it was a surprising recommendation when it came down. Usually if patients ask about it, I certainly don't discourage them from doing these exams. And I have, we've certainly identified cancers through that means before.

Starting point is 02:26:30 Well, I saw the episode of ER where the guy was having trouble breathing when he was an elite runner, and it turned out he had testicular cancer and he had overlooked the lump on his testicle, so I'm going to continue to self-screen. Okay, fair enough. Numerous times today, we've talked about the potential benefit of getting a blood test for hormone profiles, lipid profiles,

Starting point is 02:26:49 and other things as well as a sperm analysis. My understanding is that one can only do that if they have the disposable income to elect to do that through some commercial online service. But is there any way that patients who have insurance can approach their physician in a way that this would be covered by insurance. I don't want to get you into any trouble here, but it's always such a shame. It is such a shame when we're talking about something that is really pervasively related to

Starting point is 02:27:24 health, as a sexual health, reproductive health. And people are not aware of a potential problem in the present or in the future that could have been mitigated simply because they didn't get a blood test or do something as simple as a sperm analysis. So we can't be presumptuous in saying, oh, well, you know, $200 or $1,000, no big deal. I mean, for a lot of people, that's a huge deal. It's prohibitive for many people. So how can people get this stuff assessed? Should they talk to their primary care physician? Should they call a urologist? What's the best approach? I think both are good strategies. I think, you know, insurance is becoming a lot more open to covering some infertility,

Starting point is 02:28:08 at least testing, sometimes treatment as well. So I think a lot of insurance does cover that now. Sometimes we check semen analyses for other ejacatory issues. But I think that, you know, again, as more of this data gets out, I think is more recognition how important the male is, I think we'll get sort of more buying and coverage. Obviously, women have, you know, the automatic feedback of obfutory cycles, so they kind of know if there's a problem, they can. can bring that to the attention. But men don't have that feedback without some of these testing.

Starting point is 02:28:36 Yeah, and we probably should have mentioned this earlier. So forgive me, this was on me to mention that when we talk about sperm quality and we sort of shifted back and forth to semen quality, it's possible to have normal semen volume and have very low sperm count, right? We're not talking about the total amount of ejaculate per se. We're talking about the density of forwardly motile, healthy, non-DNA fragmented sperm in that semen, right? So, In other words, it's not sufficient to just assume because you can ejaculate that your sperm are healthy. That's exactly right.

Starting point is 02:29:10 Yeah, I mean, I think about 15% of men have low semen quality, whether it be concentration, movement, shape. About 1% of men have no sperm in the ejaculate, and that's something sometimes they have new idea about. So the only way to know would be to actually do a formal test. Well, I'm encouraging people to get these parameters assessed, and I'm making that statement because it's very clear based on everything that you've told us today that sperm quality and hormone levels are

Starting point is 02:29:37 just oh so important not just for sexual health but for urinary health and for reflecting prostate health and other aspects of whole body health and sexual health relates directly to mental health. I know we didn't talk so much about the psychogenic issues but the two go hand in hand. I want to thank you so much for coming here today and sharing so much knowledge with us. I mean, these really are the issues that males think about and wonder about and have questions about. And they do so to varying degrees, depending on where they're at in life. But I think especially for younger men who are hearing this, who are not at the point where they want to conceive, it's really important to start thinking about these issues for all the reasons

Starting point is 02:30:28 you mentioned. I think these issues are really important for women to know about us. as well, just as it's important for men to understand female reproductive health and not just to improve communication, but this, after all, is at the heart of the presence and proliferation of our species. So thanks for taking care of the male half and thanks for doing the work you do. It's incredible. The large-scale studies, the more detailed studies on smaller populations, you asked the questions that it seems many people are just afraid to ask

Starting point is 02:31:03 and you get right in there and come out with the really rigorous data and answer. So thank you so much for what you do. My pleasure. Thank you. Thank you for highlighting men's reproductive health. Thank you for joining me for today's discussion with Dr. Michael Eisenberg.

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Huberman Lab - Improving Male Sexual Health, Function & Fertility | Dr. Michael Eisenberg

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