Audio long read: Is the peptide craze backed by science? The promise behind the hype

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0:16ACAST powers the world's best podcasts. Here's a show that we recommend. Go touch grass. You have probably heard this phrase. Maybe you have even said it. But beneath the sort of lighthearted nature of this meme is something very real and important. A growing sense that staying in touch with our humanity and being present in our bodies matters more than ever in today's digital world. My name is Manoush Zamorodi, and I am taking over as host of TED Talks Daily this week to explore what technology is actually doing to your body and mind. In special interviews with scientists, doctors, parents, artists, and more, we're going to dig into your physical and mental health on tech.

1:06How we think about our bodies differently now. How we relate to new innovations that are amazing but also a little scary. And how we can live a healthier life in this high-tech era. Tune in on TED Talks Daily wherever you listen to podcasts.

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1:37This is an audio long read from Nature. In this episode, is the peptide craze backed by science? The promise behind the hype. Written by Cassandra Williard and read by me, Benjamin Thompson. Peptides have become the latest cure-all trend on social media. A way to eliminate wrinkles, build lean muscle, boost metabolism, clear brain fog, heal-torn ligaments, and more. Influencers rave about their peptide-fueled glow-ups on TikTok. Bodybuilders exchange information about their favorite combinations at the gym. U.S. Health Secretary Robert F. Kennedy Jr. is a proponent. I'm a big fan of peptides, he told US podcaster Joe Rogan in February.

2:26I've used them myself and used them with really good effect on a couple of injuries. Peptides are made of the same building blocks as proteins, but are shorter, typically less than 50 amino acids long. And they can be powerful medicines. The hugely successful GLP-1 diabetes and weight loss drugs, for example, are peptides, as is the hormone insulin. But when wellness gurus and fitness enthusiasts talk about peptides, they're often referring to an alphabet soup of chemicals, BPC-157, MOTC, and TB-500. These compounds come in vials labelled for research use only, because they are not approved for use in humans.

3:14It's a, quote, completely unregulated industry, end quote, says Vikas Patel, an emergency medicine physician at Elmhurst Hospital in Illinois. The popularity of peptides has skyrocketed over the past couple of years. Google searches on the term worldwide rose from about 1.3 million each month in 2024 to around 8 million per month in 2026. The enthusiasm has been driven, in part, by social media. The influencer crowd has sort of created this perception that these are miracle drugs, says Matt Cableine, a longevity researcher at the University of Washington in Seattle. And although the obsession is a global phenomenon, people in the United States seem particularly enamoured with them, says Patel.

4:03He attributes the phenomenon to a growing suspicion of the medical establishment in the country. We've hit this tipping point of people not trusting physicians or science, says Patel, who has also co-founded a private longevity clinic. Patel doesn't sell or prescribe peptides, but says that he does point people to the most reliable vendors if they decide to seek them out. But what does the science say? Animal research suggests that many of these experimental peptides hold promise for treating certain conditions. The evidence that these compounds work in people, however, is lacking. That hasn't stopped Kennedy from pushing to make them more accessible.

4:45In April, the US Food and Drug Administration, the FDA, which he oversees, began the process of removing regulatory hurdles that prevent many of these compounds from being made in specialised pharmacies. Former FDA official Peter Lurie, now Executive Director of the Center for Science in the Public Interest, a non-profit organization in Washington, D.C. that advocates for evidence-based food and health policies, worries that authorizing pharmacies to make and sell unproven therapies will deter companies from investing in drug development. It reduces the incentive, if not abolishes it entirely, for people to bring potentially effective drugs to market through the drug approval process, he says.

5:28And then what we'll have are a bunch of peptides on the market being sold and nobody generating any evidence to separate out the effective from the ineffective. Peptides occur naturally in the human body and perform essential functions. They serve as growth factors, neurotransmitters, antimicrobials and more. Tens of thousands have been identified and many more probably exist. Although made of the same amino acid building blocks, peptides are much shorter than proteins. Some arise when larger proteins are cleaved. Insulin, for example, comes from a larger protein called pro-insulin that is split in the pancreas.

6:09Others are encoded by the human genome, but not by the 20 ,000 to 25 ,000 canonical protein coding genes that have been identified. Rather, they are part of the dark proteome, hidden in vast swathes of DNA and once dismissed as irrelevant, says Pinkas Cohen, a geroscience researcher at the University of Southern California's School of Gerontology in Los Angeles. These hidden peptides expand the scope of the human genome to possibly a million genes. Peptides are attractive as therapeutics because they tend to be smaller than proteins and bind more specifically to their target than to small molecules.

6:53They generally have less off-target interactions, says Carrie Haskell-Luevano, a peptide chemist at the University of Minnesota in Minneapolis. But peptides also come with some drawbacks. They aren't as stable as proteins, and they often degrade quickly in the body. These are challenges that can be overcome, Haskell Luevano says. In fact, they already have. Nearly 100 FDA-approved drugs are peptides, including oxytocin, human growth hormone, and the GLP-1 drugs. Around 150 more are in clinical trials. Peptides can be very powerful substances, says Paul Knopfler, a stem cell biologist at the University of California, Davis, who has been following the debate over peptides closely.

7:42And, he says, quote, there is no reason to think there aren't going to be dozens of other peptide drugs that are going to be proven safe and effective, end quote. Cohen began to get excited about peptides a couple of decades ago. He and his team had started mining mitochondrial DNA for peptide encoding genes and synthesizing the molecules to study their function. One of their finds was MOTS-C. In mice, the compound prevented obesity and insulin resistance and improved physical performance. It even extended lifespan. It worked so well that COBAR, a company co-founded by Cohen and Nir Barzalai at the Albert Einstein College of Medicine in New York City, licensed the MOTS-C patent.

8:29COBAR tweaked the compound to make it more effective and more stable. and then, in 2018, tested it in a safety study. Researchers first administered the compound to 65 healthy adults to determine dosing. They then randomized 20 people with obesity and non-alcoholic fatty liver disease and gave the compound to about half of them for four weeks. Participants who received the peptide had lower glucose levels, greater reductions in markers of liver injury, and a trend towards weight loss compared with the placebo group. Cobar raised US$80 million to get the drug through an initial trial. But, says Cohen, In 2023, the company shut down.

9:19That hasn't stopped MOTC from becoming one of the most popular unapproved peptides. Quote, guys, it's like you have unlimited energy, end quote, raves one Instagram user. Other popular unlicensed peptides have been studied in even fewer people. Flynn Maguire, a physician specialising in physical medicine and rehabilitation at the University of Utah in Salt Lake City and his colleagues, delved into the literature on BPC-157, a peptide that purportedly helps to repair tissue injuries. They managed to dig up three pilot studies with a total of 30 participants. The amount of human data that exists for it is of dubious enough quality that you can essentially just ignore it, he says.

10:07There are no long-term studies. There are no safety studies, even in animals. To complicate matters, people who use peptides often inject multiple compounds together as stacks. One popular combination, called the Wolverine stack, after the Marvel Comics character, consists of BPC-157 and TB-500, a fragment of a larger peptide called thymocin beta-4. The combination hasn't been tested in humans, but clinical data do exist for thymocin beta-4, including a phase 3 trial of eye drops for dry eye syndrome. The treatment failed to meet the goal of the trial, but testing is ongoing. Deepak Srivastava, a cardiac stem cell biologist at the Gladstone Institute of Cardiovascular Disease in San Francisco, California, is more interested in what thymocin beta-4 can do for the heart.

11:04He and his colleagues found that the compound helps heart muscle to regenerate after injury, and he suspects that it might play a part more broadly in reversing aging. But he doesn't think it should be used in a do-it-yourself fashion for general wellness. It's really remarkable that this trend has started, he says. It reminds him of the raft of stem cell clinics that have popped up around the world promising to cure myriad ailments. People pay a lot of money out of their own pocket, even though there's absolutely no reason to think any of this would work, he adds. Peptides such as BPC-157, MOTC and TB-500 are widely available from vendors who market them for research purposes.

11:50What people are shooting up out there is what I would give to mice, Cohen says. Many enthusiasts call this the grey market, but, quote, there's nothing grey about it, end quote, Kaeberline says. Quote, it is illegal for people to sell experimental therapies on the internet for human consumption, end quote. The FDA can, and sometimes does, crack down on these companies, but enforcement is sporadic. Because there's no regulatory oversight of the labs that manufacture these peptides, the purity varies widely. In a pre-print study, researchers examined publicly available data for 14 peptides from a third-party testing platform that evaluates the purity and abundance of the substances.

12:35Out of about 6 ,000 samples from 203 companies, more than 40 % failed to meet even basic purity and dose standards. And of the roughly 250 samples that were tested for endotoxins, a marker of bacterial contamination, 15 % had low but measurable quantities. Endotoxins can cause symptoms that range from fever and chills to, at high levels, septic shock. Those safety concerns are, in part, why Kennedy says he is pushing the FDA to allow specialised pharmacies, known as compounding pharmacies, to manufacture peptides. Compounding pharmacies typically prepare medicines or formulations of medicines that aren't commercially available, including personalised dosages or allergen-free recipes.

13:24But they are subject to some regulatory oversight, unlike the labs that currently produce research-grade peptides, so quality control might be better, and consumers would need a prescription to access these drugs. In April, the FDA removed 12 peptides, including BPC-157, MOTC and TB-500, from a list of substances that compounding pharmacies are barred from making. This doesn't yet give pharmacies clearance to produce them, but the FDA's Compounding Advisory Group will meet in July to assess whether seven of these compounds should get the green light for manufacture by these pharmacies. It's good that they're going through the advisory committee, that's a step in the right direction, Lurie says.

14:08But the committee currently has at least six vacancies, and Lurie is concerned about who might fill those slots. I don't have any trust that we will get an honest and rigorous review of the data, he adds. In response to detailed questions from Nature about the FDA's handling of peptides, a representative from the US Department of Health and Human Services responded with a link to the advisory committee meeting scheduled for July. Lurie worries that the FDA might allow manufacturers to market peptides as supplements, alongside vitamins, minerals and plant and animal extracts. In a public FDA meeting in March, a supplement advocacy group argued that peptides are a dietary ingredient.

14:50We've been eating peptides our whole life. You probably ate a few this morning, said Daniel Fabricant, head of the Natural Products Association in Washington, D.C. In April, Kennedy testified before the U.S. Congress. When asked about his view on peptides, he said, quote, peptides are like supplements, end quote, in that the FDA doesn't require pre-marketing safety studies. Quote, supplements are not regulated in that way by the FDA. Peptides are not supposed to be regulated, end quote, he added. Allowing compounding pharmacies or supplement manufacturers to produce peptides would provide consumers with a legal supply, but it's not clear whether it would make these products safer.

15:33These are experimental therapies that haven't been fully tested in clinical trials, Kabeline says. Quote, we don't know if they work, and we don't know what the long-term safety profile is, end quote. BPC-157, for example, supposedly helps to heal tissue damage, in part by promoting the formation of new blood vessels. Patel wonders whether that could also promote tumour growth. Quote, it probably could, and we won't know unless there's a trial done, end quote. Srivastava has had similar concerns about thymusin beta-4, which promotes blood vessel formation and makes cells move faster. I'm not saying that people shouldn't take this because it could make their cancers grow, but from what we know about how it functions, that's a theoretical possibility, he says.

16:21Researchers are hopeful that consumer interest in peptides might translate to more funding for research or new interest on the part of pharmaceutical companies. But that doesn't seem to be happening yet. Cohen has been chasing investors and drug companies to push forward the development of MOTC. I'm trying to figure out, is this whole peptide craze good for this or bad for this, Cohen says. Shepherding a drug from the lab through clinical trials is enormously expensive, and pharmaceutical companies might not want to invest in a compound that is already readily available. Cableline says that he suspects that many of these peptides simply don't work well enough to grab the interest of pharmaceutical companies.

17:02They have biological activity and they may have benefits in certain indications for certain people, he says. But, quote, none of them are as effective as the GLP drugs. If they were, pharma would have developed them already, end quote. But there's another obstacle too. The FDA approves drugs to help maintain health, not to enhance it. That's not how they view the world, says Robin Bognor, a pharmaceutical development scientist at the University of Connecticut in Storrs and former member of the FDA's Compounding Advisory Committee. She was removed in 2025, about one year before her term was up.

17:40There's not a clear path to approval for wellness peptides, Bokner says. Cohen says that the current obsession with peptides makes him uncomfortable. When he first started hearing about people injecting MOTC, quote, it was a curiosity, end quote, he says. With more popularity, it became more worrisome. I'm very concerned about this whole trend, he says. The more people use them irresponsibly, the more issues I predict. To read more of Nature's long-form journalism, head over to nature.com slash news.

18:27could have even greater meaning at creativeplanning.com slash impact. ACAST powers the world's best podcasts. Here's a show that we recommend. Go touch grass. You have probably heard this phrase. Maybe you have even said it. But beneath the sort of lighthearted nature of this meme is something very real and important. A growing sense that staying in touch with our humanity and being present in our bodies matters more than ever in today's digital world. My name is Manoush Zamorodi, and I am taking over as host of TED Talks Daily this week to explore what technology is actually doing to your body and mind.

19:14In special interviews with scientists, doctors, parents, artists, and more, we're going to dig into your physical and mental health on tech. how we think about our bodies differently now, how we relate to new innovations that are amazing but also a little scary, and how we can live a healthier life in this high-tech era. Tune in on TED Talks Daily wherever you listen to podcasts.

19:43ACAST helps creators launch, grow, and monetize their podcasts everywhere. ACAST.com