Robert F. Kennedy Jr. is known for advocating natural health choices, such as consuming “real food” like meat and vegetables and opposing ultra-processed foods. He has also controversially suggested that nutrition and vitamins could be an alternative to vaccines for combating measles, a claim that is not supported by scientific evidence.
However, Kennedy diverges from his natural health philosophy in one significant area: he supports the use of experimental drugs known as peptides. This stance has raised concerns among public health experts, who argue that these substances have not been adequately researched for effectiveness or potential side effects, such as an increased risk of cancer.
As interest in peptides grows, with many seeking them out on unregulated markets, Kennedy expressed on Joe Rogan’s podcast in February that he expected the FDA to soon make these drugs more accessible. This would involve reclassifying about 14 drugs, allowing compounding pharmacies to offer them again following a 2023 regulatory change under the Biden administration. “I’m a big fan of peptides,” Kennedy stated, noting their personal benefits in treating his own injuries.
The seeming contradiction between Kennedy’s support for unproven peptides and his insistence on more research into well-established vaccines highlights a form of medical libertarianism prevalent in American health attitudes, according to Lewis Grossman, a health law professor at American University. In his 2021 book “Choose Your Medicine: Freedom of Therapeutic Choice in America,” Grossman points to historical instances like the 1970s backlash against vitamin regulation as examples of this trend.
“The aim is not necessarily to block vaccine approvals but to eliminate mandates,” Grossman explained, adding, “This reflects the belief that people should be free to take whatever they choose.”
This embrace of peptides aligns with the individualism that fuels the Make America Healthy Again movement and reflects the wellness industry’s appeal to the belief in achieving a healthier, more optimized self.
The health risks of peptides
Synthetic peptides, a category of short-chain amino acids, include well-known drugs like insulin and GLP-1 weight loss medications. However, contemporary discussions often focus on newer peptides with names like BPC-157, TB-500, and CJC-1295. These have limited research backing claims of benefits like injury healing, muscle growth, anti-aging, and energy enhancement.
Kennedy is part of a prominent group in the health and wellness sector promoting peptides. Joe Rogan advocates their use, as do Gary Brecka, a biohacker and Kennedy supporter, and Stanford neurobiologist Andrew Huberman. This influential trio ensures that American men, and increasingly women like actress Gwyneth Paltrow, are exposed to numerous peptide endorsements.
Advocates often argue that the widespread use of peptides without reported issues indicates their safety. “This is a significant gamble,” said Paul Knoepfler, a cell biology professor at UC Davis, via email. “Potential risks, such as cancer, may not be evident for several years.” Most existing data comes from animal studies rather than human trials.
One frequently mentioned concern is the cancer risk associated with peptides that promote cell growth. “Growth hormone-related peptides like CJC-1295, Ipamorelin, and Tesamorelin pose potential cancer risks,” cardiologist Eric Topol noted in his newsletter last year.
Immediate health issues can also occur. ProPublica reported two women were hospitalized critically after peptide injections at a longevity event. Authorities could not confirm if the peptides or contamination caused their illness. Contamination is a significant concern, especially with gray and black market drugs, often from China, where peptide imports doubled in early 2025. According to New York magazine, 30% of tested peptides were mislabeled or contaminated.
A brief history of peptides
Peptides were once mainly linked to elite athletes. Researcher Luke Turnock learned of them in the 2010s, when bodybuilders sought out these drugs for muscle growth and injury recovery.
By 2020, Turnock encountered a gym-goer using BPC-157 for tennis elbow, sourced from Amazon. “That’s when I realized, this is suddenly way more mainstream,” said Turnock, a criminology senior lecturer at the University of Lincoln, who studied peptide users in online forums. Although Amazon has removed injectables, oral BPC-157 remains available.
Turnock attributes the peptide surge to significant changes in the past decade. Social media amplified health influencers, spreading peptide awareness beyond gyms to fitness and anti-aging enthusiasts.
GLP-1 weight loss drugs made injections more acceptable, and compounding pharmacies became a common source. Although the Biden administration banned 19 peptides in 2023, some remain available. The pandemic also encouraged drug experimentation, as seen with hydroxychloroquine and ivermectin.
Some seek peptides for specific issues like low energy and inflammation, but they are often marketed to those curious about achieving peak well-being. “They’re trying to sell this idea of, you take this, and you will be better than well,” Turnock explained.
People exploring this often engage in the risky practice of combining multiple drugs, which may interact unpredictably. A popular example is the “Wolverine stack” of BPC-157 and TB-500, named after the X-Men character’s rapid healing powers. The U.S. Anti-Doping Agency banned BPC-157 in 2022 due to health risks. Topol observed that TB-500 accelerated dormant tumor growth in animal studies.
Peptides and the right to self-determination
The appeal of “pop peptides,” as Knoepfler terms them, lies in their promise of self-directed health improvement through the right drug combination, diet, and exercise.
This do-it-yourself approach often values personal anecdotes over scientific research, making warnings about peptide risks less impactful if negative experiences aren’t shared online. In contrast, vaccine fears can spread quickly via social media.
This outlook aligns with the “right-to-try” philosophy, as expressed by physician Gabrielle Lyon on Jillian Michaels’ podcast. “I believe people should have physical autonomy. … As long as it doesn’t quote-‘hurt’ them, they should be able to choose.”
The question remains whether peptides could harm people, as research is inconclusive. The context is crucial in assessing risks, Knoepfler noted, with different considerations for those with serious illnesses versus those in stable health. Under Kennedy, “the FDA is in the strange position of both having to still do its jobs such as properly enforcing regulations and laws, but also soon to open the door to unproven things like peptides and stem cells,” he said.
Kennedy acknowledges concerns, stating on Rogan’s podcast that “they’re still looking at the science.” His main reason for allowing pharmacies to distribute 14 restricted peptides is to enhance product quality.
Before the 2023 rule change, Kennedy said, “compounding pharmacies were getting those peptides from FDA-inspected facilities,” including India and China. In contrast, black and gray market peptides are “very, very substandard.”
While reclassifying peptides could improve supply quality, Grossman warns that broadening this argument could make it difficult to ban substances with high demand. Knoepfler remains skeptical of making peptides more accessible, but changing the FDA’s stance might portray the agency as progressive and counter perceptions of prioritizing profit over patient care. It could also give peptides a legitimacy they currently lack, as Huberman’s recent post suggests, positioning them as closer to medications than supplements.
“I predict peptides will change everything re public health discourse for health & disease,” Huberman said.
Regardless of future research findings, peptides are already pushing biohacking into the mainstream, one vial at a time.
STAT’s coverage of chronic health issues is supported by a grant from Bloomberg Philanthropies. Our financial supporters are not involved in any decisions about our journalism.
