The Peter Attia Drive - #246 - AMA #45:  Pros and cons of GLP-1 weight loss drugs and metformin as a geroprotective agent

Episode Date: March 13, 2023

View the Show Notes Page for This Episode Become a Member to Receive Exclusive Content Sign Up to Receive Peter’s Weekly Newsletter In this “Ask Me Anything” (AMA) episode, Peter focuses the discussion on two topics getting a lot of attention recently. He first dives deep into GLP-1 agonists, most notably semaglutide and tirzepatide, which originally came to market as diabetes drugs but are now being studied and prescribed for weight loss. He walks through the data and compares the effectiveness of the two drugs, the side effects, and perhaps more importantly, his reservations around wide use of these drugs and who he would consider to be a candidate for them. Next, Peter discusses how metformin, another drug originally brought to market for diabetes management, gained popularity as a potential longevity drug even for non-diabetics. Peter gives his take on this possibility and reviews data from a more recent study investigating the question of whether metformin should be used for general “geroprotection.” If you’re not a subscriber and are listening on a podcast player, you’ll only be able to hear a preview of the AMA. If you’re a subscriber, you can now listen to this full episode on your private RSS feed or our website at the AMA #45 show notes page. If you are not a subscriber, you can learn more about the subscriber benefits here. We discuss: The hype around semaglutide, tirzepatide, and other GLP-1 agonists for weight loss [2:30]; Overview of GLP-1 agonists and why these drugs are getting so much attention [6:15]; Defining the term “geroprotective” [13:30]; Semaglutide: background, brand names, indications, and more [15:15]; Tirzepatide: background, brand names, indications, and more [19:15]; How semaglutide and tirzepatide compare in their efficacy in terms of weight loss and other metabolic health metrics [23:45]; Data showing sustained weight loss and improved metabolic metrics with after more than a year of using semaglutide and tirzepatide [29:00]; What happens to body weight when a patient discontinues the medication? [34:45]; Noteworthy side effects of GLP-1 agonists and similar classes of drugs [40:45]; Increased resting heart rate and other concerning trends in patients using GLP-1 agonists [45:15]; Changes in body composition (body fat and lean muscle) in patients on GLP-1 agonists [50:45]; Possible reasons for the loss of lean muscle mass and tips for protecting lean mass [59:00]; GLP-1 agonists and thyroid cancer [1:01:30]; Who might be a candidate for GLP-1 agonists? [1:03:45]; The large financial cost of this class of drugs [1:08:30]; Metformin as a geroprotective drug: origin of the idea that metformin could be a longevity agent even for non-diabetic patients [1:11:30]; A 2022 study on metformin sheds more light on the question of whether metformin should be used for “geroprotection” in non-diabetics [1:21:00]; Peter’s current approach with metformin for his patients [1:25:15]; and More. Connect With Peter on Twitter, Instagram, Facebook and YouTube

Hey everyone, welcome to a sneak peek, ask me anything, or AMA episode of the Drive Podcast. I'm your host, Peter Atia. At the end of this short episode, I'll explain how you can access the AMA episodes in full, along with a ton of other membership benefits we've created. Or you can learn more now by going to PeterittiaMD.com forward slash subscribe. So without further delay, here's today's sneak peek of the Ask Me Anything episode. Welcome to Ask Me Anything, AMA episode number, and once again, joined by Nick Stenson. In today's episode, we focus on two topics, both of which are getting a lot of questions lately.

The first is GLP1 agonists, most notably Semaglutide, also known as Ozempik and Wigovie, and Terzepatide. These weight loss drugs are all the rage right now, and there is probably not a day that goes by where someone isn't asking me my thoughts on them. So in the first part of this episode, we dive very deep into these, what they are, their differences, how they're marketed, how they came to market, meaning what we learned about them when they were just being used as diabetes drugs, what we know about them clinically because we've been using these drugs sparingly for about three years, most importantly, I think, where my reservations are, and I do have many reservations that I discuss here.

If you're thinking about taking these drugs, if you're taking these drugs, if you're curious about them, this episode is for you. The second part of this podcast, we go a little deeper into Metform. And this is something I've talked about in the past, but a little more attention has come up lately. Just by way of background, Metformin has gathered a lot of interest over the past few years, but a lot of it goes back to a study that came out in 2014 that suggested that Diabetics taking Metformin actually had better health outcomes, i.e. lower mortality than non-diabetic, not

taking metformin. This is a very counterintuitive finding, and of course, it suggests that metformin is indeed zero protective. Well, in this episode, I dive much deeper into that assumption, both going back to the original 2014 study and looking at a more recent study that uses a very similar analysis but on a different population. So, if you have any interest in Metformin, if you have any interest in GLP1 Agonists, this is the episode for you.

Now, if you're a subscriber and want to watch the full video of this podcast, you can find it on the show notes page. If you're not a subscriber, you can watch a sneak peek of the video on our YouTube page. Without further delay, I hope you enjoy AMA number 45. Peter, how you doing? Doing very well. You ready for another AMA here? I am. We got some fun topics, two main ones that I think people are going to be interested in, but one thing I realized, although not at the time of this recording, but by the time this is released, will be about two weeks out from the book launch. Did you ever think we would be able to use those words two weeks out from the book launch?

No, no. This book is like a cat that died eight times and somehow managed to eke out survival before the ninth and final death. Well, and there's no turning back now, right? Like, if we're recording this and something went wrong, where the book's coming out, like, I just can't imagine what it would be. It's going to print. It's done. Right. Cover looks good. Cover looks great. We'll have a dedicated book podcast coming up for listeners where we kind of talk about it Like let people know what's going on But yeah, it's kind of mind blowing if you think about by the time people are listening to this

It's about two weeks out until they get their hands on it. Yeah, well, I hope it delivers Peter, I think what we're going to talk about today is really two different subjects both of which we've covered a little bit in the past But there's been a lot of new insights that have come out, new studies, new information, and we receive a lot of questions on them. And the first is something you and Bob covered back in AMA 29, which was back, I think, end of 2021. And I remember at the time you guys were talking about, hey, we're going to do an AMA on GLP1 agonists and these drugs, and it was kind of one of those things where I hadn't really heard much being talked about.

It seemed so new and, you know, I was kind of like, are we sure we want to do this? And you and Bob were both like, yeah, just wait. There's going to be a lot of talk about this. We were so wrong and so right. So we were way too far ahead of the curve talking about this. In fact, our first real discussion about it was in the spring of 2020. No, no, in the spring of 2020. So in the spring of 2020, we did a journal club internally, got very deep in the rabbit hole. By the fall of 2020, we were putting patients on.

One of the drugs we'll be talking about today. Some of Glutide a year later, we're doing an AMA on it. It's still very under the radar. And today, I would say this is the single most talked about drug period. There cannot be a drug that is getting more attention right now than some of Glutide and its ill, right? So that means branded ozempic, branded wigovie, tazepatide, branded, like all of those drugs, which we're going to talk about today, I don't think a day goes by that I'm not getting pinged by somebody about it.

So we were way too early on it. And so we're going to come back and talk about it with a much greater clarity. And also, I have a much, much stronger point of early on it and so we're going to come back and talk about it with a much greater clarity and also I have a much much stronger point of view on it today than I did two almost three years ago. And that's why I think it's going to be good to touch back on it is because not only do we get so many more questions because of how much it's talked about but I know you have so much more experience with this. So you have so much more experience with this in clinic and other things where you have a lot of new insights. So that will be the first piece. And then the other piece that we're going to cover is going to be kind of looking at some metformin data and kind of thinking about how you're thinking about that drug in particular. Not so much as for people who are diabetics, but more so for those who are in the camp of

kind of taking it as a geroprotective long-jebody agent. So, all goes according to plan. That's what we will cover today, which I think will be really good. And so, I think it will be really important just to catch people up a little bit. And I don't think we have to go into so much detail because we do have AMA 29. And if anyone wants to get in the science, that in classic Peter Bob fashion really dives into the science. But do you want to just give people a quick overview of the GLP1 drugs and why people are so excited about them, why they're talked about so much?

You're absolutely right. If I were to rehash everything Bob and I spoke about two years ago, we would not get through the content of this podcast. I really do want to talk about different things today. That said, you have to have at least a modicum of understanding of what these hormones do in the body. So we're really going to be talking about two hormones today, GLP1 or glucagon-like peptide one and GIP, glucose-dependent insulin-otropic polypeptide. Both of these are hormones that are released from the gut. I'm not going to go into the details right now. One is released from one part of the gut, one is

released from the other, but the net net is their effect on insulin. Now, you might be saying, well, why are we talking about this again? Pull up the figure, Nick. We've a figure that I think is kind of an elegant way to put all of this in context. You've got to understand that these drugs really started as drugs to take care of patients with type two diabetes. Again, what is type two diabetes? Type two diabetes is a disorder of carbohydrate metabolism. Blood glucose gets too high, and that is the defining feature of it now. You could argue, that might not be the right defining feature, maybe we should be defining it earlier on, but it's basically a very extreme state of insulin resistance. So in a person who is developing type 2 diabetes, their cells, most notably

their muscle cells, but also other cells in the body, such as the liver, are becoming resistant to the effects of insulin. And as such, their blood glucose levels are rising. The reason for that, of course, is that the muscle is the most important storage depot for glucose. And so, if the muscles are resistant to the effect of insulin, glucose will accumulate in the bloodstream. So, what are we to do about this? There are lots of things to do about it, but what this figure shows is that an important strategic plan

is using things that either stimulate insulin to be released and or inhibit glucagon release. Both of those things will have the same net increase, which is to lower blood glucose. Both directly, because if you stimulate insulin release, you're going to put more insulin into circulation, that's going to overcome at least transiently the insulin resistance in the muscle. Now, of course, that turns into a very slippery slope because you can only play this game for so long before you basically exhaust the pancreas' capacity to produce more and more insulin, and at some point you just end up having to use exogenous insulin. The inhibition of glucagon release conversely changes

the way that the liver puts glucose into circulation. And so as you can see in this figure, without going into all the details, GLP1 and GIP act through both of these arms. They stimulate insulin resies. This is endogenous insulin production, and they inhibit glucagon release. And the net effect of both of these is a reduction of blood glucose. Just for anybody looking at the figure, not relevant to this discussion, but there are a different class of drugs called DPP4 inhibitors that act further upstream of all that. So we have this observation, which was that people who were taking GLP1 agonists were not only improving glycemic control, which you would expect, but were also losing weight. And the question was, well, why are they losing weight?

And as we discussed a few years ago, and as I'm going to tell you again today, we don't have a really clear explanation for why. Virtually everybody who's had any clinical experience with these and who has looked at the literature agrees that it's clearly a central effect, meaning there is something about these hormones that is changing our appetite, namely, of course, reducing our appetite. And so when you take these hormones, your appetite goes down, you eat less, you lose weight, relatively straightforward. But the exact why is not clear, meaning it's not exactly clear why GLP1 is acting centrally

in reducing appetite. Let's take a look at the next figure as well, just to put in a broader context, all of these drugs. Again, this is all through the lens of type two diabetes. So the goal in type two diabetes, at least the end goal is to lower blood glucose. I would take some issue with that. I would say that the goal should be to increase

insulin sensitivity, which will result in a reduction in blood glucose. But let's put that aside for a moment. What you see here is lots of different drugs, two of which we're going to talk about today. We're going to talk about metformin and metformin really acts primarily to reduce glucose production. It's going to reduce what's called hepatic glucose output. Maybe it increases glucose utilization in the muscles. I think that's far less of an effect.

You look at a figure like figure two, and you might come to the conclusion that those are equal. I don't think that's the case. There's another class of drug we're not going to talk about today, but it's a very important class of drug, and it's a class of drug we have spoken about before. We've talked about this on the podcast with Rich Miller, and that's the SGLT2 inhibitors, specifically we spoke about one called Kinega Flosen. So these

are drugs that act in the kidneys, and they impair glucose reabsorption. So you end up peeing out more glucose. The reason we've spoken about them before is not in the context of that, but rather in the context of the benefits on longevity as a result of that. So that form and we're going to talk about today less because of its diabetic effects. We're going to talk about it through its geroprotective effects and SGLT2 inhibitors will definitely come back to because they're super interesting. I think that Kinega Flows and its derivatives are very promising drugs in the geroprotective space. But just so you can see it, this is how they're acting in the diabetes space. You have sulfonia erias and you have these Inchrotin therapies that we're going to talk about

today. So in a rather large nut shell, that's the backdrop to what we're talking about here. And I think it's important, maybe just to kind of remind people that even though that graph we just looked at was all about antidiabetic drugs. I'm assuming and I think you'll confirm that a lot of people who are reaching out to you to ask questions on these GLP-1 drugs don't have diabetes, correct? Oh yeah, it goes without saying that everybody who's reaching out to me on this topic and that's ranging from friends to patients to random people I don't know. Virtually none of these are people with type 2 diabetes. These are people that are asking the question solely through the lens of weight loss. And I want to be clear, some of these people are in genuine need of weight loss. Some of these people are walking around with 50% of their

body weight in body fat or 40% of their body weight is fat. But perhaps more disturbing to me is the people who are reaching out to me who are frankly not overweight remotely, but are saying like, I really want to lose 10 pounds to look good on my vacation. And I should be taking this right. And so, you know, again, those are some of the things that I want to be able to address. People who have listened to podcasts for a while, we're familiar with this term, but it might be good to just give a super quick definition because we've used it twice now. When we say, geoprotective, that's just a fancy way of saying, do you want to explain to people kind of what you mean by that?

Geoprotective is sort of a, I mean, it's its name suggests, georogue aging protective. It's a term we use to describe drugs whose exact mechanisms of aging might not be known, but they appear to act broadly across various different hallmarks of aging might not be known, but they appear to act broadly across various different hallmarks of aging. So I would argue that lipid lowering drugs improve longevity, but I don't think I would call them zero protective because they're kind of just acting not on a hallmark of aging, but rather on one very specific element, which is like the proteins, and those, of course, do factor very heavily into ASEVD and to a lesser extent dementia.

But contrast that would say, rapamycin or SGLT2 inhibitors or potentially metformin, where they're probably doing a lot of things that overall improve lifespan and health span beyond just whack emoling one disease at a time. And you mentioned it and I'll just give people a podcast number but Richard Miller that episode was number 148. I think it's such a fascinating episode and for people who kind of want to understand the science of these drugs, what goes into testing them, what to think about, can't recommend that enough. Richard Miller, just amazing insights, and that podcast was great.

So anyone who hasn't listened to it, 148 definitely go back to it. I think the next question that we get a lot is, you know, when the AMA 29 came out with you and Bob, I think just some agglutide was on the market and being talked about, but 2022, you mentioned it, Trezepatide came out and also is showing some really good results. And I think one of the common questions people have is what's the difference between these two drugs and kind of how do they compare? To be clear, there are other versions of this drug, other versions of GLP1 agonist that came earlier, not going to talk about them right now.

So the first time this ever popped up on a MyRateR was like 2013. That was a drug that was used for type 2 diabetes and never gained FDA approval for obesity. At least I don't think it ever did. But let's start with semi-glutide. So semi-glutide is a pure GLP1 agonist. To be more clear, it has a comparable affinity to pure GLP1. So, one way that we do that, there's a chemical way that you can look at the concentration of semiglutide and ask the question, how much of it do you need to replicate the effect of pure GLP1? In the case of semi-glutide,

it's on the order of half as potent. But nevertheless, it's a pure GLP1 agonist, meaning it's replicating. As opposed to antagonists, you sometimes hear that in pharmacology antagonist block the effect of hormone. So the branded name for semi-glutide in the use for type two diabetes is called ozempic.

And it comes in three doses, I believe, 0.51 and 2 milligrams. These are auto-injector pens that need to be refrigerated. They're very expensive. We're going to talk about that later. So a patient who's historically been getting this retreatment of their type 2 diabetes, hopefully they're not paying out a pocket for this. They're either giving themselves 0.5 or 1 or 2 milligrams of this drug. And they're doing it weekly, which by the way speaks to something I should have said earlier. Remember how earlier I said that semi-glutide is not quite as potent as the actual

GLP1, as the native GLP1. And you might say, well, why didn't they make it that way? And the reason is it was designed that way. It was designed to have a much longer half-life. If you're thinking about drug delivery, how long the drug stays in circulation is really important. So if you could make native GLP1, but it only stuck around your system for six hours and you had to inject yourself four times a day.

That's a much worse tradeoff than say being able to have it slightly less potent and just use a greater dose of it, but only inject yourself once a week. So anyway, a little less side there. So basically, ozemic as semi-gluteide was approved in late 2017. We'll talk a little bit about the data for why that was the case. I think a higher dose was actually approved just last year. Now, fast forward to, I think it was June of 21. The study came out, I think, in April of 21,

that looked at semi-glutide. It was actually using ozempic, but the indication was in treating obesity without diabetes. We talked about that at length in the previous AMA, and we will touch on it briefly today. But nevertheless, that led to the approval of a new drug called Wigovie, which is of course the exact same drug. So semi-glutide is ozempic is wagovi. The difference is basically branding and dosing. Wagovi is dosed up to 2.4 milligrams per week, and that was approved, as I said, probably in the spring of 21, and it was just recently approved for kids age

12 and up at the time of this recording last month. I hope that kind of makes sense before I go on to Teresepa tide. I think it does and it's kind of good to just hear, I think anyone who watches TV will have seen commercials and you see Mugovie, Ozempik, you see stories about something good tied. So I think it's a good overview of just different terms, similar things. I think it's a good overview of just different terms, similar things. So now we will switch and talk about a newer drug called Terzepatide. Terzepatide is not the same as Semiglutide, and it is in fact a drug that is known as a co-agonist.

So it is both GIP and GLP1. And you'll recall, I said that semiglutide is, you know, directionally speaking, about half as potent as native GLP1. Well, tersepotide is even less than that. Tersepotide, when you use the same sort of chemical, as a called the KI or an affinity metric, it's a quarter as potent as native GLP1. However, when you compare the GIP activity, it's virtually identical to native GIP. So you think of semi-glutide as a slightly weaker version of GLP1.

You would think of Terzepetide as a much weaker version of GLP1, but a very potent GIP. It's basically equivalent biologically to GIP. So this is branded as a drug called Manjaro. Is it worth pointing out our text thread on this topic? It's really funny. You brought that up because one of the things I was going to say is rumor is that your alias is Johnny Manjaro because of your affinity for this drug.

Can you confirm or deny that? I will absolutely deny it. I do have an alias and it is not Johnny Manjaro, even though there are people within our organization that are trying to make that happen, but no, it is not. I have a much cooler alias than Johnny Manjaro. Although, I would admit, that's a pretty cool alias. It's got a good ring to it. It kind of rolls off the...

It's like a man of mystery, Johnny Manjaro. You don't know what he does. No, no, it's insane. I mean, I hope that somebody listening to this adopts that moniker and is forever more, Johnny Manjaro. Okay, so Manjaro, which is just a branded name for Terzepatide, comes in same thing. It's a preloaded pen that you inject, so you don't have to draw it up or anything like that.

It comes in increments, I believe it's 2.5, 5, 7.5, 10, 12.5, all the way up to 15 milligrams. It was approved relatively recently for type two diabetes. So that approval took place like a year ago, relatively new drug. It has not yet gained FDA approval for obesity. However, the New England Journal of Medicine did publish a study in the fall, which is where a lot of the hoop law came from, that demonstrated that this is even a better drug than semi-glutide for weight loss. And presumably, they're in the process of now gaining approval for obesity use.

Of course, because a drug is approved by the FDA, you can basically use it for anything you want. It's just considered off-label, and it would never be approved by insurance companies. But for people who are willing to pay out of pocket, there are lots of people who are both being prescribed and using Terzepatide or Mungaro for the purposes of obesity. And of course, just to be clear, whatever approval comes for obesity, it's going to have a new name. So just as you have wagovie for obesity and ozempic for type 2 diabetes, you have Mungaro for type 2 diabetes, and you're going to have some equally bizarre name for obesity. This may be a naive question, just I don't know the science as well. Well, either of these drugs ever be non-injectable,

like will there ever be a day in which you can take a pill, or because of what they do in the body, do we think they'll always have to be injectable? Oh, not a naive question. In fact, there is an oral semi-gluteide as well. I'm blinking on the brand name. It begins with an R. It's like RY something. It is used somewhat for type 2 diabetes.

That's its indication and approval. It's also very expensive. And I'm not exactly sure of what the differences are and why one would prefer it over the injectable. The only thing I can think of is if a person doesn't want to inject, doesn't want to use a needle and or refrigeration is a problem because obviously these things need to be refrigerated. So that might be kind of an issue there. That's what I was kind of figuring. I assumed someone was trying to figure it out just for those people with a fear of needles is injecting yourself as often as you would have to, would be a little tough. Now that we got the overview, the next question we always get is, how do those two drugs, simglutide, trosepatide, compare in their effectiveness?

So in looking at weight loss, HBA1C, those other things that they're measuring, do we see a difference in the results, and kind of what do we know about that? Thank you for listening to today's Sneak Peak AMA episode of the Drive. If you're interested in hearing the complete version of this AMA, you'll want to become a member. We created a membership program to bring you more in-depth, exclusive content without relying on paid ads. Membership benefits are many, and beyond the complete episodes of the AMA each month, they include the following.

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