GLP-1 may slow biological aging

7 hours ago (universityofcalifornia.edu)

I'm always confused with these type of posts because I feel the scientists must know something I don't. Why is it always does GLP-1 help with [general health thing]?

If I understand it correctly, GLP-1 drugs help people with weight loss. People are more healthy when they're not overweight, and GLP-1s help people get down to a healthier weight. So when we ask questions about do GLP-1s help this or that, isn't there a giant confounding variable here? That being overweight causes a litany of health issues has been common knowledge forever now. Thus, my (uninformed, intuitive) guess would just be that GLP-1s, which cause weight loss, also include the subsequent effects of healthy weight loss.

So why are we surprised then that people going from overweight to a healthy weight slows aging, or betters cardiovascular health as I've seen elsewhere? Aren't these already well-studied effects of healthy weight loss? Shouldn't these positive effects obviously just be attributed to weight loss, rather than the thing that causes the weight loss? And why are there articles about this stuff acting like this is unexpected?

I admit I'm a laymen and I hope don't sound too snide or critical here. I'm just kind of puzzled by this out of genuine curiosity.

  • As another person commented, we currently believe the primary mechanism behind the pleitropic effects of GLP-1's to be a reduction in systemic inflammation and direct improvements in vascular/endothelial function.

    The best paper I've seen on this was the recently published and very aptly named:

    "Pleiotropic effects of GLP-1 receptor agonists — a narrative review of extra-metabolic outcomes in adults" (2026)

    https://journals.viamedica.pl/medical_research_journal/artic...

  • 1. Yes, for many of the benefits of GLP-1s, it's plausible the mechanism is weight loss. But actually achieving significant weight loss with other therapies is incredibly hard, so I think GLP-1s get some credit here.

    2. Hunger signalling isn't the only thing GLP-1s do, so no, we should not just assume every effect stems from weight loss alone. E.g. the blood sugar regulation that makes them very effective for diabetes is not purely about weight management.

    • Stress eating is also a thing, so if we’ve misunderstood a chemical pathway that we created an agonist for it can be a little of column A and a lot of column B.

      We have failed blood pressure drugs that turned into boner pills. We have failed blood pressure drugs that reduce social anxiety. In the field of medicine we have a lot of people acting like we understand the body but we don’t know shit. It’s a bit like how physics was “nearly done” before relativistic and quantum physics were discovered. We still don’t know shit. And we are going to kill or fail a lot of people between now and when we can find our asses with both hands.

  • There is another plausible causal mechanism: weight gain flowing from hunger/metabolic dysregulation. This dysregulation being caused by some "factor X" which also causes other problems.

    GLP-1 then addresses factor X, and the problems it causes, including weight gain.

    Not that obesity doesn't independently cause problems but very plausible causality runs more than one way.

    • I would use the word "possible", not "plausible". GP's scenario is plausible since it doesn't need positing an as of yet unknown factor X.

  • These studies control for such variables, confounding effects are easy to think of, but 9/10 times here on HN, the authors DID control and adjust for that confounder, the commenters just didn't read the methods.

    • Eh, no, the vast majority of splashy headline studies that make it to HN show some associative result where causality is not established. They can not control for all possible confounding. The money sentence from the study is "semaglutide was associated with significantly reduced epigenetic aging relative to placebo across multiple generations of epigenetic clocks."

      https://www.nature.com/articles/s41467-026-72861-3

      It kinda seems like a bunch of markers moved randomly and some of them happened to move together: "In contrast, causality-enriched epigenetic clocks28 AdaptAge, CausAge, and DamAge exhibited directionally heterogeneous and statistically non-significant changes." That gets you a publication but I don't know that I'd bet money on follow-up study results.

  • When you see reporting like this it means there was some study that had some evidence of some effect that somewhat matches the description in the headline, but nothing more than that. How good of a study it was, how large the effect, how in alignment or not it is with a body of evidence, how reproduceable it is, how exaggerated the press release is. Are all left out and are all critical to how much anyone should care about the statement. What it definitely does not mean is "all scientists are asserting this truth in the headline"

  • GLP-1 probably reduces systemic inflammation, with far-reaching consequences. That is a much bigger effect than just losing weight, though weight loss contributes to that.

    Then there are the mental effects, such as people reporting that they lost various addictive habits (gambling, compulsive shopping etc.)

    • I mean sure sure, I get that, but take this article I found from a simple Google search.

      https://www.health.harvard.edu/heart-health/weight-loss-drug...

      I get that science has to be thorough, but how is it at all worth writing about that losing weight makes your risk of heart attacks lower? That GLP-1s are involved suddenly makes this news?

      Again, not trying to be snide. I'm on the side of science here, but there's gotta be something the scientists are looking at that I'm not.

      2 replies →

  • Glp1s aren't just appetite suppressants. Two identical people doing and eating identical things -one on glp1 and one not - the one on willose more weight and have better biomarkers like insulin sensitivity

  • >“GLP-1 receptor agonists are being shown to benefit many chronic diseases over and above their effect on weight,” John Deanfield, FRCP, FESC, professor of cardiology at the Institute of Cardiovascular Sciences at University College London, told Medical News Today. “These include liver diseaseTrusted Source, kidney diseaseTrusted Source, diabetes, and neurological diseasesTrusted Source such as Parkinson’s diseaseTrusted Source. They should therefore not be labeled merely as ‘weight loss’ drugs, but as drugs that can have a direct effect to improve patients’ health.”

    >Building off this research, Deanfield is the lead author of a new study recently published in the journal The LancetTrusted Source that provides further evidence of semaglutide and lowered major cardiac event risk, regardless of how much weight a person loses while taking the GLP-1 medication.

    >“Semaglutide has previously been shown in the SELECT trial to significantly reduce major adverse cardiovascular events in overweight/obese patients with known heart disease but without diabetes,” Chen explained. “This study analyzed the information from the SELECT study, and found that this benefit to cardiovascular health did not depend on how overweight patients were or how much weight they lost.”

    >“This interesting finding suggests that the cardiovascular benefits of semaglutide act through a biochemical mechanism not dependent simply on changing the body weight of an individual,” he continued. “This may open up other avenues of research and therapies that could improve heart health.”

    https://www.medicalnewstoday.com/articles/weight-loss-drug-h...

  • Yeah!

    These scientists, whose job it is to think about this really hard, why didn't they just think of the most obviously obviously thing? I'm sure they didn't!

    ...

    Dude. Come on.

    • I was abundantly clear about this exact thing in my comment.

      I even asked, explicitly, “what do the scientists know that I don’t?”

      I asked despite the question sounding dumb, because that’s what you do when you genuinely want to know more!

I'm excited to see more studies done in this context, but without the HIV association. My wife has Ehlers-Danlos Syndrome and Rheumatoid Arthritis. She saw more benefits in inflammation reduction than weight reduction, especially those first two weeks she started taking it. She says her pain levels are night and day difference when on GLP-1 vs off. To me it would then make logical sense that reduced inflammation can have a measurably positive effect on aging.

Isn't being "underweight" generally shown to reduce the speed of aging

  • Came here to say this. Also caloric deficits.

    • Probably you both really mean the same thing.

      Every gram of body weight needs energy to stay alive. If you are in a caloric deficit, you will lose weight until your energy expenditure matches the caloric intake. If you stay in "caloric deficit" forever you will actually starve by definition.

      Properly defining what you mean (comparatively low caloric intake without defining it via the current weight) is actually quite tricky, as your height, body composition and physical activities are all inputs to what counts as a "normal" caloric intake.

    • I saw reports on that before the GLP1 craze. Calorie reduced diets for lab animals generally increased their life span.

>They also reduce visceral and ectopic fat that accumulates around the abdomen and organs, which may help curb the inflammatory and metabolic signals that promote aging.

Interesting, I wonder if someone will do a study where they pair a GLP-1 with tesamorelin to see if there's any synergy there in terms of fat reduction and reduced aging.

> slows down the accumulation of biological aging markers in the DNA of adults with HIV

And if you don’t have HIV?

Let's play spot the conflict of interest. Three of seven authors tied to a company selling biological aging tests. One consults for Merck, GSK, etc.

There seems some promise at times but I also struggle to see the recent slew of "GLP-1s cure X", where X is seemingly any ailment known to man, as much more than the next Big Pharma gold rush where the profits dwarf any eventual regulatory fines, and taxpayers and real patients are left with the costs.

  • No matter what drugmakers spend money on, you hear complaints:

    - Marketing, to learn what / whom / how to sell: “They spend more on TV ads than R&D!”

    - Basic R&D: “Look at all the conflicts of interest in this academic research!”

    - Commercial R&D: “They’re just looking for ways to extend the patent lifetime of drugs that only exist because of government-funded basic R&D!”

    - Back to the shareholders (mostly pensions and retirement accounts): “Billions of stock buybacks for Wall Street!”

    What should the pharmaceutical companies with billions coming in from GLP-1’s be spending their money on?

    • Both opinions can be true, drugmakers should still spend money on R&D, and consumers should hold academic research with significant financial ties to interested sponsors to a higher standard of scrutiny.

      Criticism does not have to mean preventing work, we can be critical especially of work that we find important.

    • You may be right that they are in a bind wrt public opinion. But that is not a defence against any specific criticism. What is your opinion on the conflict of interest mentioned above?

      11 replies →

    • I'm inclined to agree with your point, but it seems like there's an obvious thing they could do that I think people wouldn't complain about: Reduce their prices. Of course that would just look like not getting so many billions from GLP-1 drugs, rather than like any specific action one could complain about.

      (If anyone reading this feels inclined to say something like "But how would that benefit them?" -- well, if you restrict consideration to things they could do that benefit them, then it no longer seems so unreasonable if all their options look bad to the critically-minded. Maybe they should be doing things that benefit the rest of the world more and themselves less.)

      3 replies →

    • One thing they are spending them on is tons of new research. Lilly is spinning up massive facilities in Indiana, of all places. I know some absolutely fantastic researchers at Indiana University but I had never thought of it as a biotech hub before.

      1 reply →

    • Much like the conspiracy that pharma companies are uninterested in curing diseases, the complaints aren't based on data or facts.

      I'll offer cystic fibrosis as an example. Trikafta may as well be a miracle drug. And CRISPR-based gene editing and replacements are being researched that could be an outright cure, as opposed to a 90% cure.

      1 reply →

  • I am EXTREMELY skeptical of epigenetic clocks at the moment, and have been for a few years, but at the same time it's important for these clocks to be investigated and shown to be what they are.

    Even though I personally expect them to be readouts of things that don't affect healthspan much, I don't have any more evidence than those trying to work out what they are. I've been wrong before, and also most tech development does not end up living to its promises, but without the investigation we'll never know.

    > Big Pharma gold rush where the profits dwarf any eventual regulatory fines

    With pharma malfeasance, the penalties are actually big enough, unlike most other fields. Unless you have something particular in mind?

    • > I am EXTREMELY skeptical of epigenetic clocks

      I hear that word and I immediately think of "that" guy that runs the cocktails of additive interventions to "improve" it.

      1 reply →

  • Valid questions.

    What would you propose instead? Who will do this research, with what funding, and why will they want to do it? And why would we trust that research more than this? Wouldn’t we scrutinize research carefully regardless of the source?

    There are multiple alternative systems, as we see in other countries. But they all have tradeoffs and some really only make sense if some international entity is doing research somewhere else under a different set of rules.

    • No. This is what we have government for. The self-interested are the least qualified. They are simultaneously paying to market the drug (which involves exaggerating or lying about its capabilities and minimizing or hiding its drawbacks.)

      This certainly seems like something a national health service (or even insurance company) should be doing in its own interest (in order to direct spending), and wouldn't have any intrinsic bias towards any particular outcome other than an accurate one. The problem is that you need a government that is not also owned by the drug company.

      In the US we have an enormous amount of government health care spending that would benefit from more knowledge about the effects of these drugs. There's no reason why we should ever take the drug company's word for anything. The research was likely originally done in an academic setting, and likely largely government-funded. The only reason the drug companies get these drugs from that environment is through corruption.

      > The Bayh-Dole Act made a key change in federal contracting procedures that allowed contractors the right to retain ownership of inventions made with federal funding.

      https://en.wikipedia.org/wiki/Bayh%E2%80%93Dole_Act

      1 reply →

  • I don't understand this fixation. If you literally had a cure for X for X in all ailments known to man, you would in fact have a Pharma gold rush.

  • it's low quality research. you don't need to point to perceived conflicts of interest. the drug is semaglutide, not a merck or gsk product. and semaglutide is coming of patent anyway

> randomized, placebo-controlled clinical evidence

:)

> data from a...clinical trial of 108 adults with HIV associated lipohypertrophy

:(

  • They work on that group because (as the article says) they show increased aging relative to a normal group, making it easier to detect effects in a relatively short running study.

  • > howunfortunate

    I have never seen a user name better fit a hacker news comment.

    This also perfectly sums up the whole emotional roller coaster of modern science communication.Oh that could be cool (title)... Hey this might be good work... Fuck thats depressing I will never get this time back.

Everyone I know that are using these looks gaunt and sickly. They also complain of constant nausea and eat like a bird because eating makes them sick O_o. We’ve all seen the “glow” of people that lost weight with diet and exercise — it is not that. I’m glad they exist but worry about the side effects of long term use and medical professionals not using it as a brief intervention then steering towards lifestyle changes.

  • > Everyone I know that are using these looks gaunt and sickly.

    This is a statistical fallacy where you're only identifying the extreme cases. The average obese person loses 14-20% of body weight. (Remember that the "obese" category is already defined as 20%+ above the high end of the "normal" range.) So the vast majority of people on these drugs just look normal, not skinny or gaunt.

    > They also complain of constant nausea and eat like a bird because eating makes them sick

    This is a high dose phenomenon. They can and should reduce their dose if it is preventing them from eating enough or being comfortable.

    > I worry about ... medical professionals not using it as a brief intervention then steering towards lifestyle changes.

    They absolutely do, of course.

  • Most professionals DO steer towards lifestyle changes. They probably look gaunt and sickly because their excess skin sags and they may temporarily look older due to stretchy skin.

  • Everyone I know that is using these looks just fine. Better than before, as they’ve lost weight.

    This is why anecdotal evidence is pretty bad.

  • I think a lot of this is that being overweight makes you look fluffy and younger - being just a little "overweight" even makes you look healthier.

    So people who were fat and get to a normal weight, if you've always known them as fat then they look like they've aged a decade or two in a year. People who were totally normal weight (i.e. "overweight" according to BMI, which is associated with a longer lifespan than "healthy weight") end up looking like tuberculosis Romantics because they wanted to look like movie stars (who are often on severe, unhealthy diets that they stop when they're not working.)

    Losing weight quickly often loses it badly - think meth addicts. Women lose fat from their breasts and both sexes lose the fat pad around the eyes; I think these are generally stable fat stores that don't really replenish after being used, even if you gain the weight back. It's not specific to GLPs, just quick weight loss. If you'd lost more slowly your body wouldn't have resorted to taking from those places. Now, you have super-deep nasolabial folds and marionette lines.

    > lost weight with diet and exercise

    You lose weight through diet. You gain fitness through exercise.

I've lost 6kg of fat (I've maintained muscle mass) in 2 months with only the 0,25mg monthly dose using Wegovy.

This is one of the most interesting ideas in medicine right now

This feels like the early days of medical marijuana where everything was sunshine and rainbows, and then 10 years later we realize yes, there are still drawbacks.

  • yes a weight loss drug for a country that is over 70% overweight is absolutely the same as a psychoactive drug with well-understood cognitive side effects and abuse risk, a perfect analogy

  • A take you knew was so dumb that you had to create a new account to post it.

  • There is a gold rush happening where every health influencer, telehealth prescriber, and even aging services provider (as is the case with some of these study authors) is trying to push this medication for a wider audience.

    Medical marijuana was different, though. The negatives were known medically before and after. The push was almost entirely political and on social media. The few places medical marijuana were medically pushed were either for highly specific applications or as a harm reduction measure: Either as an alternative for patients who demanded opioids (medical marijuana isn’t actually a viable substitute for opioids in severe high level pain, but it’s common for patients to demand to be prescribed something “stronger” for lesser conditions and there was a real problem with opioid over prescription at the time) or from the sector of medicine that sees that patients are seeking out drugs anyway and thought this was a better way to control and monitor it. The way it worked out in practice became a laughable loophole where anyone who wants a card can pay $100 for a meeting with a prescriber who will give leading questions until you say the right things to get the card, which wasn’t even what the original medical marijuana proposals were about.

    In the medical and research world, there was never an illusion that marijuana was actually entirely harmless and without drawbacks, except for fringe papers and a few politically motivated researchers.

If the DunedinPACE test is so accurate and cheap now, there must be hundreds of people that have a baseline and also measurements after taking GLP’s… also why do you need a double blind if you have this amazing biological ageing test?

Presumably mediated by caloric intake reduction, which is already known to slow aging?

I'd be more suspicious of what side effects this thing has.

  • FDA approval of the first GLP-1 agonist was in 2005 and many diabetics have been taking these drugs for close to 20 years, so we have a pretty good picture of what long term side effects are: mostly GI symptoms, and you can have problems with muscle loss and bone weakening if you lose a ton of wieght. otherwise they are well tolerated.

  • Been on one for a few years now, it tempered my persistent auto-immune issues. Short term side effects are barely present for me. This stuff has made it so I don't have to be on steroids and antibiotics every other month. I did not start the medication for weight loss purposes, though have lost 10-15lbs, but I attribute that to being off steroids.

    Long term? Who knows for sure. Semaglutide has been approved for 9 years. Liraglutide was 2009 and hasn't shown thyroid issues still. Exenatide has been available since 2005.

    GLP-1s aren't new and haven't shown widespread negative issues beyond gastrointestinal upset, and that is typically fixed by... drinking more water. The trials in rats have pointed towards potential thyroid cancer risks but those haven't been seen in people.

    • There is reason to have some healthy skepticism for pharma. But I am sometimes astounded by how unshakably cynical people can be.

      I suppose we all could wind up with cancer in 10 years or something hypothetically, due to some unforeseen mechanism. But here's my story.

      I went from 200lb to 140lbs at 5' 9" over 3 years. I feel great. I don't need to eat 1000 calories before bed just to sleep through the night. I focus better at work. Blood pressure is back to normal. HDL is back to normal. I can run without joint pain. I feel good about myself. I feel comfortable going on dates. I'm not a near-obese shut-in loner that can't be in a caloric deficit without wrecking my sleep.

      Unless there are literally fatal side effects, these drugs seem pretty miraculous.

      1 reply →

  • Its been decades since it was invented so perhaps we'll find out soon.

    • I don't know, let's restrict it's use just to be safe. Unproven, unresearched peptides though, we should have the FDA bless them for sell.

  • It would be pretty funny if it turns out it doesn't have any side effects and it really is just a silver bullet.

  • I wonder if people were waiting for horrible side effects to be found after antibiotics were invented.

but what about the people with a BMI already under 20?

not like we can take GLP-1 even if it was affordable

btw soluble fiber helps people naturally secrete more GLP-1 but of course not on the same level as a dedicated drug

Jesus Christ is there anything this thing can’t do?

  • I have been injecting this stuff for months now with no weight loss

    • If you're getting it compounded it may be time to switch providers.

      Seriously, in the first week you should feel a bit of nausea at .25mg. After 2-3 weeks you should see something, either weight loss (most) or gain (some).

      Or you could be one of those who have no effect, which sucks. I'd go over your process with your provider, from storage to injection.

      2 replies →

    • One of my reports at work started out with heavy diabetes and 300 pounds. Now he’s down to under 200 and has no diabetes less than 5 months later.

      2 replies →

    • glp1 doesn't increase your basal metabolic rate, it curbs your appetite. so it's still possible to ingest an excess of energy and to maintain your energy storage volume if you continue the dietary habits that got you fat in the first place -- eating slop and/or eating for the sake of eating.

      even one caffeinated corn syrup slurpee that people consume like it's no big deal can be a quarter or more of your daily energy requirement. a few snacks on top of that and that leaves preciously little budget for real food.

  • I'd assume most of what it does is a due to losing weight and reduced metabolism due to lower caloric intake.

Of course it does. /s

How much are the pharma companies paying people to project this nonsense to trick people to take these drugs to make money out of it?

This is the new grift.

They also cause sexual dysfunction while you're taking them. Not a problem I guess when you're overweight, but on weight...it's a huge problem.

  • Or put another way, "Let me pluck one of the rare side effects and make it seem like its a common one because I know nothing about this"

  • That's not a common side effect, and I've been watching GLPs for years. In fact, it's more likely to cause divorces due to, you know, becoming more attractive.

If two cars are each three years old, but one has had twice as much gas consumption as the other, which would you expect to show more wear on its comppnents?

Caloric churn is putting the body's systems through their paces - at the very least for everything related to digestion. But really most of life is well described as pieces of a metabolic process.

  • Comparisons like this, while seeming to make sense using “common sense” rarely impart any value or scientific meaning. Maybe it works like that, maybe it doesn’t.

    If as a result of less caloric consumption you’re starving your cells of needed nutrients, maybe that’s the one that degrades earlier.

  • This is such an oversimplification of complex biological processes that it borders on medieval superstition.

  • Should we similarly expect those who use their muscles more to be in worse condition than someone who doesn’t exercise?

  • Oxygen is a reactive species, that's how we do what we do. How we swim the thermodynamic eddies and flows across quadrillions of chemical reactions.

    But burning that fuel is damaging.