What Are Peptides and Why Are They Trending?
Wellness enthusiasts, biohackers, social-media influencers, and celebrities are injecting experimental “anti-aging” peptides in growing numbers. They hope to boost energy, lose weight, sleep better, heal injuries, enhance libido, and even get tanned. The FDA has not approved most of these therapies. Many people buy them online from the unregulated “gray market,” often sourcing them from suppliers in China. Little clinical evidence supports their effectiveness or safety, and many doctors warn of serious potential risks.
“There isn’t any meaningful data on these peptides,” says Dr. Eric Topol, a cardiologist, longevity expert, and director of Scripps Research Translational Institute. “People are taking them on blind faith.”
Peptides are short chains of amino acids — the fundamental building blocks of proteins. In the human body, they play a critical role in immune function, hormone production, and cellular repair. Skincare products such as collagen supplements and creams commonly contain peptides. The FDA has also approved dozens of peptide drugs, most of them injectable. Insulin and GLP-1 drugs for diabetes and obesity rank among the best known.
Despite the lack of regulatory approval, peptide therapies are surging in popularity across social media. Tens of thousands of users on TikTok, Reddit, and Instagram share stories about their “stacks” — combinations of peptides they experiment with. Celebrities including Jennifer Aniston and Gwyneth Paltrow, and prominent podcasters Joe Rogan, Andrew Huberman, and Dr. Mark Hyman, have publicly endorsed their potential health-boosting benefits. Even Robert F. Kennedy Jr., Secretary of the U.S. Department of Health and Human Services, has vowed to end the FDA’s “aggressive suppression” of peptide therapies.
Which Unapproved Peptides Are People Using?
A growing number of people are using injectable peptides that have never undergone rigorous clinical testing in humans. Popular unapproved peptides include:
BPC-157 — Users take it for injury recovery and improving athletic performance. TB-500 — Proponents claim it boosts muscle growth and reduces inflammation. CJC-1295 — Advocates say it promotes fat loss and better sleep. GHK-Cu — Supporters believe it promotes healthy skin and hair.
Some users also take FDA-approved peptides “off-label” — meaning for purposes the FDA never authorized. Doctors originally approved Tesamorelin to treat HIV-related lipodystrophy, but people now use it off-label to seek fat loss and muscle gains.
“Here is a drug shown to work in people with a very rare condition, and people are now taking it to get rid of abdominal fat to get a six-pack. It’s crazy,” says Dr. Topol. “There’s no data to support that.”
Are Peptide Stacks Safe? What Experts Warn
People on social media frequently describe experimenting with multiple peptides at the same time — either as “stacks” with names like “Wolverine” and “Fountain of Youth,” or as blended vials containing multiple peptides. Some enthusiasts argue these substances are safe because the body naturally produces them. Experts strongly disagree.
“Peptides could potentially be very potent and very toxic,” warns John Fetse, assistant professor of pharmaceutical sciences at Binghamton University. “Toxins in many animal venoms, for example, are peptides.” Fetse calls the assumption that natural origin equals safety “dangerously inaccurate.”
How the Unapproved Peptide Boom Started
Niche bodybuilder communities once kept unapproved peptides to themselves, but these substances are now rapidly “becoming mainstream,” says Luke Turnock, a researcher at the University of Lincoln who studies the rise of these drugs. Around 2010, powerlifters primarily used peptides like BPC-157 and GHRP-2 for muscle-building, purchasing them from underground sources alongside steroids.
By 2020, Turnock began tracking everyday people using the same peptides for general health and appearance improvements. A 2025 study he published found that users of all ages — particularly older men and younger men seeking physique enhancement — were turning to peptides as a socially acceptable alternative to steroids. “There’s a certain stigma attached to steroids that peptides don’t have,” Turnock notes.
Are These Peptides Legal and How Are People Buying Them?
In both the U.K. and U.S., people typically turn to the “gray market” — sources outside regulated pharmaceutical channels — to obtain unapproved peptides. A quick Google search reveals numerous websites, some posing as online pharmacies, that claim to sell these drugs. TikTok and Instagram influencers openly advertise purchase links, and suppliers in China ship most products.
Sellers commonly label these unapproved peptides “for research purposes only” and “not for human consumption” — a legal loophole that helps them bypass regulatory oversight. “By labeling it this way, suppliers could potentially absolve themselves of liability. The liability is on you, the consumer,” says Fetse.
Buyers typically purchase syringes on Amazon and learn injection techniques from YouTube and TikTok videos — highlighting how unregulated and accessible this market has become.
The Bottom Line on Peptide Therapy Risks
The peptide therapy trend raises serious public health concerns. Without FDA approval or rigorous clinical trials, users have no reliable information on correct dosing, drug interactions, contamination risks, or long-term side effects. Medical professionals consistently urge caution. Until researchers publish peer-reviewed clinical data, the risks of self-administering unapproved peptides remain largely unknown — and potentially dangerous.
