Kendra Pierre-Louis: For Scientific AmericanIt is Science quicklymy name is Kendra Pierre-Louis, I’m replacing Rachel Feltman.
In early March, the U.S. Food and Drug Administration sent a warning letter to Novo Nordisk, the maker of Ozempic and Wegovy, saying the company failed to disclose potential risks associated with taking the drugs. THE the agency alleged that Novo Nordisk failed to properly report and/or track three deaths of people who were taking semaglutide, the key ingredient in Ozempic and Wegovy.
The drugs are part of a broader class of drugs known as GLP-1, which have become very popular for everything from type 2 diabetes to weight loss, and are increasingly seen as having potential benefits well beyond those two conditions. The popularity of these drugs has led to a multitude of GLP-1 offerings flooding the market, not all of which are FDA approved.
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We sat down with Lauren Young, associate health and medicine editor for Scientific American to talk about where the GLP-1s go from here.
Pierre-Louis: Thanks for being here, Lauren.
Lauren Young: Thank you very much for inviting me.
Pierre-Louis: So, basically, what is GLP-1?
Young: Okay, so GLP-1 drugs, these are the drugs that you’ve probably heard with those funny advertising chimes. They are sold under the names Wegovy and Ozempic, which is the brand name of the active ingredient semaglutide. And then you will probably also have heard of Zepbound and Mounjaro, which are the brands of tirzepatide. So these were originally treatments for type 2 diabetes, and they have since evolved into weight loss treatments. And the reason they’re so effective is because they mimic a hormone in the body called GLP-1, glucagon-like peptide 1 – fun name.
And so this hormone basically starts the production of insulin, which is why it’s a really good drug for type 2 diabetes. But over time, researchers also noticed, “Hey, it seems like people are eating less on this drug.” » And they discovered that this also influences the level of satiety: people feel full more quickly, we eat less and therefore lose weight. So that’s basically how the hormone and the drug works because the drug basically mimics that hormone.
Pierre-Louis: And from what I understand, in general, in our body, GLP-1s are short-lived. But with drugs, they hang around longer.
Young: Exactly. Yes yes. So these drug manufacturers have basically designed them to last and stay in the body longer, because there are enzymes in the body that break down the hormone at a much faster rate, so they can last in the body for… stay active, essentially, for about a week.
Pierre-Louis: So there’s been a lot of tension in recent months about the rise of what we might call GLP-1 knockoffs, like the compounded versions. Can you tell me: What is a compound medicine?
Young: That’s right, so compounded medications are produced by compounding pharmacies. Thus, compounding pharmacies essentially create tailor-made medications for individual clinical use. So people who can’t take a medication orally, for example, might need to turn that medication into a cream or an IV drip or something like that, or children, for example, might need a lower dose. It’s the same thing with pets and zoo animals, they also sometimes take compounded medications because they, you know, need a specialized recipe for, you know, specific medications.
Pierre-Louis: For example, I injured my ankle a few years ago…
Young: Yeah.
Pierre-Louis: And my doctor prescribed me a custom anti-inflammatory lotion to put on it…
Young: RIGHT.
Pierre-Louis: And this was sent to me by a, a composer.
Young: Yeah, yeah, that’s a perfect example of what a compound drug is. These compound pharmacies therefore meet an important need. But it’s also important to note that no compounded medications are FDA approved, meaning they are not tested or reviewed for safety or effectiveness.
Pierre-Louis: Can you talk a little bit about the role that compounding pharmacies have played with GLP-1s?
Young: So, the history of GLP-1 compounds dates back to when these drugs gained popularity for a multitude of reasons. Ozempic, for example, was quite often used off-label; a lot of celebrities used it. And these drugs are also initially intended for diabetes. But then in 2021 [semaglutide] became approved for weight loss.
This essentially caused the popularity of these drugs to explode, and they experienced a shortage in 2022. Subsequently, another popular drug, tirzepatide, which is [now] sold under the names Zepbound and Mounjaro, have also experienced a shortage.
So when a drug goes into shortage, that essentially empowers these compounders to start producing it, you know, to fill those access gaps. In many ways, these compounding pharmacies have filled a very important void.
Pierre-Louis: But then they stopped being in short supply, but the preparers continued to make them, right?
Young: Yes, tirzepatide was taken off the shortage list, I think, at the end of 2024, and then semaglutide followed in 2025. And so how do these drugs continue to be compounded? Well, the way a lot of these companies get around this is, firstly, they’re allowed to be compounded if people need a specific dosage. So, for example, the Ozempic and Wegovy pens are pre-filled, so if an individual, for example, needs something higher or lower, these compounds can fill that gap.
Additionally, many of these companies are putting, quote, unquote “additives” and creating custom versions of these drugs. And these additives are very interesting. Some of these claim to contribute to potential muscle loss, as this is something that has been seen with GLP-1 weight loss drugs. Another thing is that these drugs, the GLP-1s, have a lot of nausea and gastrointestinal side effects, so some of these “additives,” quote, claim to help alleviate those effects. None of these additives have been tested for safety or effectiveness. But this is how they continue to make these drugs.
Pierre-Louis: And as a consumer, what’s the advantage of going through a compounder versus, you know, the official version from a pharmaceutical company?
Young: Often, these manufacturers sell these drugs at market prices much lower than the official versions of the drugs, and this is because the active ingredients they obtain are often cheaper. So that’s one of the main reasons is cost. And then, you know, in people who need different dosages, they’re maybe in between the designated levels in these pens. So there are benefits, for sure.
Pierre-Louis: In February, Novo Nordisk, the maker of Ozempic and Wegovy, sued one of the biggest sellers of compounded versions, the telehealth company Hims. [&] His, then dropped the lawsuit. Can you tell us a little about the origins of this trial?
Young: That’s right, so Novo Nordisk basically sued Hims & Hers because they were saying, “Hey, you’re falsely marketing your GLP-1 compounds as essentially a first-line drug instead of our drug.” » They also called them “copiers”. And these drugs under Novo Nordisk and likewise Eli Lilly, they are still under patent…
Pierre-Louis: Mm-hmm.
Young: So you can’t just create a complete copy of these drugs. That was sort of the main reason for the trial.
Pierre-Louis: But they have since abandoned it.
Young: Yes, they dropped the lawsuit last week.
Pierre-Louis: So, you know, Ozempic [is] technically a diabetes drug, and Wegovy shares the same main ingredient as Ozempic, semaglutide, but in higher doses.
Young: Mm-hmm.
Pierre-Louis: And since 2021, when Wegovy was approved for weight loss, we’ve seen sort of an explosion of GLP-1s: there’s tirzepatide, liraglutide, dulaglutide.
Young: [Laughs.] It’s a game, like knowing which of these drugs are actually real because it’s just a fun jumble of words all the time. [Laughs.]
Pierre-Louis: And over the last 15 or 20 years, these medications have been seen as helpful for type 2 diabetes and weight loss. More and more research suggests that GLP-1 may be helpful for other things, like alcohol use disorders.
Young: Mm-hmm.
Pierre-Louis: Can you talk about some of these benefits?
Young: Yes, in fact, several studies have been published on the addiction aspect of GLP-1. So it’s interesting because this all comes from sort of a flood of anecdotal reports of people just saying, “You know, I’m taking these medications, and I’m not only noticing that some of my… you know, my satiety levels are different; I’m not craving, you know, snacks and food as much. But I’m also not, you know, itching to pick my nails. I’m not craving, like, drinks anymore.” or I no longer want alcohol.
And so that really sparked, like, a wave of research in the addiction area, you know, scientists thinking like, “Okay, you know, we know that food reward pathways overlap, and we know that, often, that’s what we see in addiction as well. Maybe there’s something here for a potential treatment.”
Very recently, a large study was carried out in the [Veterans] Health system affairs. You know, they collected data from over 600,000 veterans…
Pierre-Louis: Mm-hmm.
Young: So, you know, these are mostly white, male, older individuals, you know, but it was really striking because these are also people with type 2 diabetes, and they were evaluating a variety of different uses of GLP-1. And they noticed that using a GLP-1 essentially reduced the risk of developing a substance use disorder.
And these were different types of substance use disorders: they looked at cannabis use disorders, related to opioid use, alcohol use disorders, and not only that – they also looked at people who already had a substance use disorder, and they found that it reduced things like drug-related mortality, I think, by up to 50 percent. And that’s an impressive reduction.
So it’s very attractive to people like addiction researchers. You know, I talked to, for example, a researcher who is in treatment for opioid addiction. She’s currently running trials on using GLP-1, potentially, to offset the use of some of the other treatments that…because you have to take an opioid to be treated for the disorder, so, you know, maybe pairing it might be attractive. But there’s still a lot to learn, but it’s certainly a really fascinating space.
Pierre-Louis: Are there other types of unexpected potential benefits they are seeing from these medications?
Young: We already know that Wegovy, for example, has been approved for cardiovascular risk reduction, so we’ve seen that. I am personally very interested in the field of reproductive health. And they’re also finding that using GLP-1 could also reduce inflammation, which obviously could open the door to a variety of different treatments for many types of diseases. Many interesting avenues of research are underway.
Rre-Louis tart: That said, on the other hand, you know, these drugs are not a panacea and we are discovering some things that are perhaps concerning.
Young: Yeah, so these medications, even though they’ve been around for decades, more and more people are using them. We really don’t know the long-term consequences of these medications. Just recently, an extensive analysis found that GLP-1 drugs were linked to a higher risk of skeletal disorders, such as osteoporosis.
Pierre-Louis: Mm-hmm.
Young: And we also saw that GLP-1 could be linked to loss of muscle or lean mass. That’s another thing that’s very concerning among clinicians, because when you think about weight loss, whether it’s through a GLP-1 drug, exercise, diet, or something like malnutrition, you’re losing all different, quote unquote, “types” of weight. So yes, you lose fat, but you also lose things like muscle and bone mass, and those things are important, especially in older people, and a lot of older people suffer from, you know, problems like type 2 diabetes. So, you know, there’s a lot of factors to consider here.
There’s also another important caveat: many people eventually stop taking these medications after about two years…
Pierre-Louis: Mm-hmm.
Young: I think it’s about average that they see. So there’s a lot of studies going on, like, “Okay, what happens to the health benefits that you see in people? For example, these changes in cardiometabolic health are improved when you take these medications; how quickly does that come back?” And there was a study in January that showed that it was rebounding, you know, pretty quickly. There was a study that compared weight regain after stopping a GLP-1 medication versus, for example, exercise or diet…
Pierre-Louis: Mm-hmm.
Young: And they found that by stopping a GLP-1 drug, you gain that weight back and you lose those health benefits much faster than these other means of weight loss.
And on top of that, I spoke to Rozalina McCoy, a researcher at the University of Maryland. She was very insightful about all of this. And something she pointed out is often this weight gain…
Pierre-Louis: Mm-hmm.
Young: Particularly after drug treatment it will be fat instead of muscle mass because, obviously, that’s true, maybe with exercise you maintain those good behaviors even a little bit more by exercising more regularly, or the same with your eating habits – maybe you still eat a little bit better than before, even if you completely stop a diet or, like, an intensive training program to exercise. So those are some things that researchers are concerned about.
And then the last thing I’ll also note is that there are a lot of serious gastrointestinal side effects, and that’s kind of reminiscent of, you know, people stopping after two years, so.
Pierre-Louis: It really feels like, especially if you’re using these medications for weight loss, that you should really weigh the pros and cons and really think long term, especially in the back of your head, that you might not be on these medications forever.
Young: Yeah, and I mean, that’s how these drugs are marketed now too, right? They’re marketed as — and, actually, you know, prescribed as well — as a lifelong treatment. There are so many questions around access and maintenance of treatment if this is truly the most effective way to deliver these medications, and we still need these long-term studies. And I look forward to learning more every day, so [Laughs] This is a really interesting area to talk about in health right now.
Pierre-Louis: That’s all for today! Tune in Friday when our associate editor, Bri Kane, speaks with Andy Weir, the author of the science fiction novel. Hail Mary Project. The Hollywood adaptation of the book, starring Ryan Gosling, hits theaters Friday.
Science quickly is produced by me, Kendra Pierre-Louis, with Fonda Mwangi, Sushmita Pathak and Jeff DelViscio. This episode was edited by Alex Sugiura. Shayna Posses and Aaron Shattuck check in on our show. Our theme music was composed by Dominic Smith. Subscribe to Scientific American for more recent and in-depth scientific news.
For Scientific American, This is Kendra Pierre-Louis. Have a good week!