Pick a condition – joint pain, brain fog, insomnia – and there’s probably a peptide therapy promising to treat it. Never mind that many of these amino acid products are not approved by the U.S. Food and Drug Administration, have barely been studied in humans, and may not be intended for human use at all. Some people aren’t afraid to go DIY, purchasing peptides from online retailers or overseas suppliers and injecting them at home, whether their doctor knows or not.
There’s a clear solution for regulators facing an “illicit market” like the one emerging for peptides, says Mitch Zeller, a former FDA official who left the agency in 2022: “Step up your enforcement game” to stop its spread.
His successors at the FDA, however, appear to be taking a different approach. Rather than curbing the peptide craze, they appear ready to take steps that will fuel it.
Health and Human Services Secretary Robert F. Kennedy Jr., a “big fan» peptides, seems to follow a swear to finish what he called the FDA’s “aggressive removal” of substances, including peptides. In July, a The FDA advisory committee should examine whether compound pharmacies – which manufacture drugs that are not commercially available or in short supply – should be allowed to produce certain injectable peptides. Those under study include peptides that the FDA, under the Biden administration, ordered compounding pharmacies to stop making. due to security concernsincluding the possibility of immune reactions.
And in March, the FDA held a public meeting to discuss the scope of ingredients allowed in oral dietary supplements, during which proponents of peptides advocated for their inclusion. At the meeting, FDA Deputy Commissioner for Food Kyle Diamantas said the administration’s goals include “cutting red tape.” signaling a potential opening to expanding what can be sold as a dietary supplement. Already, this category includes a wide range of ingredients – vitamins, minerals, herbs and more – which may be sold based on promises to support general health and wellness, as long as they don’t claim to treat specific conditions.
Supplements, unlike medications, do not require rigorous studies to be prove safety and effectiveness before they hit store shelves, meaning they face minimal oversight, says Zeller, who worked on supplement issues at the FDA in the 1990s. He says adding unproven peptides to these products would take the industry even further into “buyer caution.”
The FDA is still deliberating on peptides. An HHS spokesperson did not respond to questions, but instead directed Scientific news to links on the next meeting relating to pharmaceutical compounding pharmacies.
The agency’s actions, Zeller said, demonstrate a “belief in the right to try” even unregulated substances that are not known to be safe and effective. The “only conceivable outcome,” he says, is that more people feel encouraged to dose themselves with largely unstudied and unregulated peptides.
By the way, what are peptides?
Peptides are essentially “miniature proteins,” says John Fetse, a peptide therapy researcher at Binghamton University in New York. A complex arrangement of amino acids is a protein; a shorter chain of them is a peptide.
Peptides occur naturally in the body, as well as in many foods. They play a wide range of roles. The hormones insulin and oxytocin are peptides, for example, but peptides also appear in toxic animal venom. “Not all peptides are the same,” says Fetse. “How you arrange the basic elements really tells you what kind of effect you’re going to have.”
Synthetic — or lab-made — peptides can mimic those the body produces naturally, but with modifications to make the compound “more drug-like,” says Eileen Kennedy, president-elect of the nonprofit American Peptide Society. (Chemical biologist at the University of North Carolina at Chapel Hill’s Eshelman School of Pharmacy is no relation to Robert F. Kennedy.) They may last longer than natural versions or increase concentrations beyond what would occur naturally in the body.
How have peptides been studied and regulated so far?
Some synthetic peptides are well researched and approved by the FDA. (The “P” in GLP-1, the very popular category of diabetes and weight loss drugs that includes Ozempic, stands for “peptide.”) But many substances people use to self-treat, with names like BPC-157 and TB-500, show promising effects in animal studies but have not been rigorously studied in humans, raising questions about whether they are safe and effective as advertised.
For example, BPC-157, a synthetic peptide derived from gastric juice found in the stomach, has been shown to speed healing of tendon injuries And injuries in rats, but human research has been largely limited to small case reports or pilot studies. A small clinical trial on humans was initiated in 2015 but canceled before the results are reviewed and published.
Currently, BPC-157 is on the World Anti-Doping Agency’s banned list. The American Anti-Doping Agency states that this “may cause negative health effects.” Still, some people use it in hopes of improving their athletic performance, injury recovery, and more.
“Not all peptides are the same. How you arrange the basic elements really tells you what kind of effect you’re going to have.
John Fetse
peptide therapeutics researcher
Consumers should “be patient” and “see what the clinical data says” before using peptides, Fetse says.
Even peptides that closely mirror those produced by the body itself can have different effects when administered like a drug, says Eileen Kennedy. A peptide naturally found in the stomach may trigger a different reaction when injected into the knee to help heal a sports injury. Some people also take many different peptides in regimens called “stacks” and risk unexpected and potentially dangerous interactions, she says.
Some doctors are willing to write prescriptions allowing people to purchase certain peptides at compounding pharmacies — a process that still doesn’t allow for a full review of safety and effectiveness, but which at least operates within the US regulatory system.
But “many peptides do not go through this route,” explains Eileen Kennedy. Instead, many people buy them without a prescription, from direct-to-consumer websites or from overseas factories, with minimal oversight. Sometimes, she says, these compounds are technically intended for research and not for human consumption.
“In these cases, there is no real guarantee of purity,” she says. “You might not even get exactly the compound you want.”
What would the inclusion of peptides in oral dietary supplements mean?
Loose oversight also characterizes the current oral dietary supplement market, another area in which peptides are a topic of interest. Without requirements for pre-market safety and effectiveness testing, the FDA typically only intervenes if a supplement causes health problems once it’s already on sale, Zeller says.
“It creates an environment where we have legalized snake oil,” says Pieter Cohen, an internal medicine physician at the Cambridge Health Alliance in Massachusetts, who studies the safety of supplements. “You can put anything in a bottle and start selling it.”
This already includes peptides, to some extent. Oral collagen peptide supplements, for example, are already commonly marketed to support skin, bone, muscle, and joint health. A 2025 meta-analysis supported some of these claims, finding that supplementing with collagen peptides can improve bone mineral density and muscle function.
Substances already present in the food supply are also generally considered fair game to be included in the supplements. This includes certain peptides (collagen is found in meat and fish) as well as their constituent elements, amino acids. The market is full of amino acid supplements that claim to help with athletic performance and many other wellness goals. While a limited number of searches suggests that athletes could benefit from their use, other studies have been less positive.
However, many buzzing peptides are not found in the food supply. BPC-157, for example, is “not a food ingredient. It is an unapproved drug and cannot be legally prescribed or sold without a prescription,” according to the Safety operating supplementan educational project of the Ministry of Defense.
Still, it’s easy to find dietary supplement capsules that advertise it as an ingredient — and if the FDA decides to expand the scope of permitted supplement ingredients, it could become even easier.
It’s worth noting that “despite all these possibilities to include just about any chemical found in any food,” regulators may allow even more substances to go into supplements without proactive review of safety and effectiveness, Cohen says. Besides peptides, ingredients such as microbials were discussed at the March meeting.
If supplement manufacturers begin adding peptides to their products, Zeller believes they should be regulated like drugs, given the many outstanding questions about how peptides affect human health. “There should be pre-market review, both of their safety and their potential benefits,” he says.
If this review takes place, the results could be disappointing for oral supplement manufacturers. When peptides are swallowed, enzymes in the stomach usually digest them quickly. “If you swallow it in a supplement, you probably won’t see any therapeutic benefit,” says Fetse.
