If there’s a word that captures both the great promise and the persistent uncertainty of longevity medicine, it’s peptides
Proponents say peptides offer anti-aging benefits and miracle cures for a variety of ailments, while scientists warn that the claims outpace the evidence. They say vast improvements in drug delivery technology would need to be made before much of their potential can be harnessed.
Peptides are small chains of amino acids that make up proteins in the body, said Mansoor Amiji, university distinguished professor of pharmaceutical sciences and chemical engineering. They bind to receptors on cells and trigger a range of biological effects, from the regeneration of tissue to the production of hormones — making them an increasingly important class of drugs
Peptides are readily available in the human body, Amiji said, but they’re also synthesized into drugs that can be used to treat diseases, regulate metabolism and manage a variety of chronic conditions. Among the more famous and federally approved peptides are GLP-1 agonist medications, the class of drugs behind Ozempic, Wegovy and Mounjaro; insulin, a peptide hormone and drug used to treat diabetes; and collagen supplements, which are marketed as promoting healthier skin and joints.
The enthusiasm surrounding these molecules — both the naturally occurring kind as well as the synthetic variety — is that they can be engineered to target specific biological processes involved in tissue regeneration, bone healing, gut health and sexual function, among many others. Longevity and wellness influencers have promoted those purported benefits, claiming they can accelerate healing from injuries, improve physical performance and ultimately slow aging.
The fever over peptides comes as the Food and Drug Administration debates whether to loosen restrictions on peptide drugs that agency scientists say remain insufficiently studied. An FDA advisory committee met last week to broaden access to at least four previously banned peptides, allowing specialized pharmacies to manufacture customized peptide medications, or “compounds,” to be made available to specific patients who’ve obtained a doctor’s prescription.
The peptides include BPC-157, KPV, TB-500 and MOTs-C, each with intended medical uses for ulcerative colitis; wound healing and inflammatory conditions; wound healing; and obesity and osteoporosis, respectively
Those pharmacies are sometimes called compounding pharmacies, where customized drugs are produced and sold to patients with particular needs, such as those who may need tailored doses of specific medications not otherwise commercially available, experts say.
The advisory committee’s recommendation does not mean the drugs have been approved by the FDA
Steve Kates, a longtime pharmaceutical executive and expert in peptide design and manufacturing, said one of the chief concerns with some of these peptides is that they have not undergone rigorous, long-term testing typically consistent with FDA-approved medications.
Factoring in research and development, clinical trials in human subjects and finally safety reviews, new drugs take an average of a decade or more to receive FDA approval, he said
“The bar for getting a drug approved is incredibly high,” Kates said. He noted that the three pillars of an FDA finding of “safe and effective” include demonstrating clinical efficacy, validating the manufacturing process and completing the required toxicology studies. “These products haven’t gone through any of that,” he said
Peptides have existed as potential drug candidates for decades, but the process of linking the amino acids in the correct sequence — requiring repeated chemical reactions and purification — made them difficult to manufacture and incredibly labor-intensive, Kates said.
That changed after chemist Bruce Merrifield developed solid-phase peptide synthesis, a breakthrough that earned him the Nobel Prize in 1984 and dramatically simplified production of these fragile biomolecules by allowing them to be built much more efficiently compared to purification. Subsequent advances in chemistry and automation during the 1980s and 1990s made peptide synthesis routine, Kates said, which in turn allowed researchers to produce them far more efficiently.
Even then, peptide drugs remained limited by delivery challenges, Kates said. Because of how quickly they break down and are cleared from the bloodstream, most had to be injected instead of taken orally, he said. It wasn’t until the success of GLP-1 medications for diabetes in 2005 and, later, obesity in 2021 that peptides became a major focus of the pharmaceutical industry, Kates said
The revolution is both exciting and disconcerting for scientists with an eye on these drugs. Health Secretary Robert F. Kennedy Jr. has long championed the health benefits of peptides, saying they could help Americans live longer and healthier lives
The challenge isn’t simply creating a peptide that can target the right biological system, but rather getting the delicate molecule to the correct place in the body intact to work its magic, Amiji said.
To be effective once injected, peptides have to survive the body’s defenses, circulate to the appropriate tissue, enter the correct cells and even — in specific — reach structures deep inside those cells, Amiji said. Without specialized delivery systems that can better protect the delicate chain of molecules, Amiji says, many of the peptides marketed online are unlikely to ever reach those intended targets.
Kates said drug delivery is likely to improve as researchers develop new ways to transport peptides throughout the body. One approach, he said, involves packaging peptides inside nanoparticles, microscopic carriers designed to protect the drugs and help deliver them more effectively to their intended targets
“If we can solve the delivery problem, peptides could become some of the best drugs we have,” Kates said.
