People have been talking about using peptides for health for a while. And while this trend has been percolating, the details around it remain murky.
The term itself is confusing—peptides are technically short chains of amino acids, after all, and that can be used to describe a lot of things, including skincare ingredients. But peptides have a huge following in the longevity community, and they’ve recently been championed by Health and Human Services Secretary Robert F. Kennedy Jr.
Kennedy announced on a recent episode of the Joe Rogan Experience podcast that he plans to loosen restrictions on 14 peptides that the Food and Drug Administration (FDA) previously prohibited compounding pharmacies from producing. According to Kennedy, the FDA is considering taking many of these peptides off a banned list and that it could happen within the next few weeks. He didn’t list the potentially unbanned peptides by name.
Kennedy acknowledged that there isn’t robust scientific data to support the use of these peptides, but he argued that some people are getting access to them anyway. “My hope is that they’re going to get moved to a place where people have access from ethical suppliers,” he said.
Given that“peptides” can mean a range of things, it’s fair to be confused about what we’re even talking about. Here’s what doctors want you to know.
What are peptides, and what do they claim to do?
The term “peptides” is a little vague and can apply to a lot of different things. “Proteins are made up of amino acids, and when amino acids are linked together, they form peptides,” Arin Bhattacharjee, PhD, professor in the Department of Pharmacology and Toxicology at The State University of New York at Buffalo, tells SELF.
Peptides typically consist of a sequence of five to 35 amino acids, while proteins can be composed of hundreds to thousands of amino acids, Dr. Bhattacharjee explains. “From a pharmaceutical perspective, peptides are generally easier to manipulate and treat diseases with, compared to proteins,” he adds.
Peptides act as “messengers” to turn off or increase different processes in the body, like your metabolism, immune function, and wound healing Kelly Johnson-Arbor, MD, a toxicologist at MedStar Health, tells SELF. She cites a laundry list of common medications that classify as peptides, including insulin, human growth hormone, vasopressin, and glucagon-like peptide-1 receptor agonists (GLP-1s).
“There are many FDA-approved peptide drugs on the market,” Dr. Bhattacharjee says. But others— like the growing list of compounds that are buzzy among fitness and anti-aging influencers—have limitations, mostly because of safety concerns, Dr. Bhattacharjee says. Some people are using these peptides to try to build muscle, extend life, recover from injury, lose weight, and even boost their sexual desire. There’s a long list of compounds in this wellness category, but these are some of the more popular ones right now (only one of which is FDA-approved):
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BPC-157, a peptide that allegedly boosts wound healing and supports musculoskeletal recovery. FWIW, this is banned by the World Anti-Doping Agency.
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PT-141, a peptide that has been linked with enhanced sexual desire. (FDA-approved to treat HSDD in premenopausal women, but it’s not approved for use in men or postmenopausal women.)
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MK-677, which is designed to increase muscle mass and recovery.
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Sermorelin, a peptide that encourages the pituitary gland to release more human growth hormone.
“Peptides are usually injected because, if you take these orally, they tend to be degraded quickly in the stomach,” Jamie Alan, PhD, an associate professor of pharmacology and toxicology at Michigan State University, tells SELF. “They can be given orally, but this is more rare and they are hard to dose orally.”
Kennedy isn’t the only public figure championing these. In late 2025, Rep. Diana Harshbarger, who is also a pharmacist, wrote a public letter encouraging Kennedy to reevaluate certain peptides for use.
Where are people getting these?
Right now, people are getting the peptides restricted by the FDA from wellness and anti-aging clinics. “Therapeutic peptides that are not approved for human use by the FDA are often marketed as research chemicals or dietary supplements and may be sold online by compounding pharmacies or overseas retailers,” Dr. Johnson-Arbor explains.
Many of these restricted peptides are also readily available online, often from compounding pharmacies.
What’s the concern with these peptides?
There are a few. One is that these medications are currently banned by the FDA, although that could change in the near future. As of this second, it’s difficult to know for sure if you’re getting what the label suggests when you purchase one of these peptides.
But there also isn’t robust science to support the use of most of these which, again, even Kennedy admitted. There is some limited research—it’s just not as much as most experts would prefer when it comes to injecting a medication. One older study on BPC-157 found that the peptide helped to heal tendons in rats.
Another older, small study of 32 older adults found that MK-677 boosted levels of growth hormone in participants to a level that’s often found in younger adults. But this was a small study and only some participants actually took MK-677 (others were given a placebo).
The rest of the data is pretty similar—trials on humans are just not robust enough or simply don’t exist, Dr. Bhattacharjee says. As a result, Dr. Alan says she doesn’t recommend these. “I do not see a clear benefit to anyone of using [unapproved] peptides right now,” Dr. Alan says.
Then there are concerns about possible unintended consequences from taking these peptides. While some peptides encourage the release of growth hormones, “there could be cancerous or precancerous cells that one would not want to grow,” Dr. Alan says.
Because these medications are injected, Dr. Bhattacharjee says there’s a chance they may cause immune reactions, too. “Plus, companies making peptides need to make sure they’re super pure,” he says. “If there are impurities, it could lead to stronger immune reactions.”
Experts urge anyone considering a black market peptide to instead, connect with a licensed doctor who can address underlying health concerns, treatment options, and help ward off potential interactions with other medications you may be taking. “Therapeutic peptides are an intriguing facet of medicine, but most should only be used with caution and under close medical supervision, given the current lack of robust data supporting their efficacy and safety in humans,” Dr. Johnson-Arbor says.
Dr. Alan agrees. “Make sure to talk to a healthcare provider,” she says. “They are trained to help you make these decisions. Politicians are not.”
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Originally Appeared on Self