Peptides are having a moment, promoted by everyone from wellness influencers and celebrities to Health and Human Services Secretary Robert F. Kennedy Jr. as a shortcut to better health.

In fact, in February, Kennedy said plans were in the works to ease FDA restrictions that have barred compounding pharmacies from producing more than a dozen peptides for human use.

But what exactly are peptides? Scientifically, peptides are short chains of amino acids that occur naturally in the body—insulin and human growth hormone are examples. Increasingly, they appear in topical skin care products, while others—often sold as injectables—have become popular for longevity and a range of benefits, from healing injuries to building muscle.

While some show potential, experts caution that most peptides aren’t FDA-approved or rigorously studied for safety or effectiveness. Here's what to know before jumping on this trend.

What to Know About Peptides

Peptides are chains of amino acids, like proteins—but shorter and less stable. In the body, they often act as signaling molecules that trigger processes like growth and metabolism.1 “A lot of the goals of peptide therapy are to mimic either naturally occurring or already present proteins or peptides in the human body,” John Smith, MD, FACS, a board-certified general and cosmetic surgeon at Cosmetic Surgery Affiliates in Oklahoma City, told Health.

Peptides come in creams and pills, but injections are most common because that enables the compounds to bypass digestion, making it easier for your body to use.2 

Some peptide-based products are well studied and FDA-approved. GLP-1 drugs like Ozempic, for example, are perhaps the most familiar (the “p” stands for peptide). But many of the trendy ones touted online lack approval. They are typically offered by compounding pharmacies (some marketing them under the guise of being for research purposes) or online retailers, some based outside of the U.S., and can cost hundreds or even thousands of dollars.

On the Joe Rogan podcast, Kennedy said he wants the FDA to reclassify 14 (of 19) peptides from the agency’s Category 2 to Category 1, allowing them to be produced by compounding pharmacies covered by Section 503A of the Federal Food, Drug, and Cosmetic Act. These pharmacies have fewer restrictions than those covered by Section 503B.3

Do Peptides Work?

In theory, many peptides should work for their designated purpose, given that they’re designed to mimic processes that already happen in the body, Smith said. And proponents online say they’ve had success with peptides. 

Still, the scientific evidence simply isn’t there yet for many of these products. “Peptides fall into a gray area where there’s a lot of promise, a lot of potential, a lot of theoretical advantage and benefit to be gained, but some are still lacking long-term follow-up data on safety and efficacy,” Smith said. 

Erika Gray, PharmD, a pharmacist and co-founder and chief medical officer of Genestyle, agreed. “Peptides are the Wild West because we have very little data on them,” she said, noting that most research so far has been done in cells or animals, with little on humans.

Are Peptides Safe?

Likewise, there just isn’t enough evidence to say whether many of these products are safe. Because many peptides haven’t been studied extensively in humans, there are no established standards on correct dosages, how long you should take them, or if long-term use could potentially disrupt other biological processes—especially among young users. It’s also not clear if “stacking” multiple peptides for different purposes could lead to any negative side effects, Gray said.

What Experts Recommend

Before buying or using peptides, experts recommend consulting a physician. But if you move forward without guidance, it’s especially important to pay attention to where a product is coming from.

One red flag is when the source doesn’t require a prescription. That can signal the product is coming from an unregulated manufacturer, said James J. Chao, MD, FACS, a board-certified surgeon specializing in medical weight loss and the cofounder of VedaNu Wellness. 

There are also signs of a more reputable company. According to Chao and Gray, trustworthy brands clearly list ingredients and dosages, explain how and where products are made, and provide third-party testing for purity, potency, and sterility.

Gray also cautioned against using peptides as a quick fix. If you’re dealing with an issue like poor sleep, for example, the root cause could be a mental health condition, hormonal changes, or a medication—none of which would necessarily be improved by a peptide. “This is an area people should be even more cautious about, because there are several other pathways that should probably be addressed before reaching for a peptide,” she said.

Overall, experts urged caution with peptides until more rigorous testing and oversight are in place. “As a professional opinion, I can’t honestly recommend something we don’t have good safety data for,” Smith said.