‘People are turning themselves into lab rats’: the injectable peptides craze sweeping the US | Well actually

Here’s a new trend that seems reckless: purchasing unregulated substances from dealers in foreign countries and injecting them into your body.

And yet, gray market injectable peptides—a category of substances with obscure alphanumeric names like BPC-157, GHK-Cu, or TB-500—have developed a devoted following among biohackers and health optimizers.

On platforms like Discord and Telegram, users claim these peptides help with everything from injury recovery, athletic performance, weight loss, mental function, better sleep, and younger-looking skin.

Among the Bay Area’s risk-tolerant tech workers, peptides have become a status symbol. The founders of startup Superpower store vials of peptides in their office refrigerator for convenient back-of-lunch injections, and at least one “peptide rave” in San Francisco saw partygoers entertained by a man in a white coat demonstrating how to inject liquid peptides.

What exactly are injectable peptides?

Peptides are short chains of amino acids – smaller versions of proteins – that play a role in regulating hormones, releasing neurotransmitters and repairing tissues, explains Adam Taylor, director of the Clinical Anatomy Learning Center at Lancaster University. More than 100 drugs approved by the Food and Drug Administration are peptide-based, including insulin and newer GLP-1 drugs like Ozempic.

In contrast, gray market injectable peptides are not approved by the FDA. Unregulated investigational compounds lack reliable safety and quality control data. Sometimes these substances are essentially illegal versions of approved drugs, such as semaglutide, but are purchased for a fraction of their market price from online dealers.

While some injectable peptides are completely foreign to the human body, others, like BPC-157 and TB-500, are synthetic versions of proteins naturally found in us, where they play a role in tissue and cell repair.

“These two are popular because when you combine them, they get the exciting name ‘Wolverine Stack,’ based on the supposed similarities to the film character’s regenerative properties,” Taylor explains.

But just because a protein plays a natural role in the body doesn’t mean a lab-made version will provide additional benefits. “These two compounds alone have never been shown to have any benefit to justify their therapeutic use in humans,” says Taylor.

While preclinical animal and in vitro studies suggest that certain peptides may help speed healing of musculoskeletal injuries such as fractures and torn ligaments, animal studies do not always translate to humans.

“We’re not seeing data that sets the world on fire,” Taylor says.

So far, research trials have not prompted regulatory agencies to approve these substances or convinced companies to invest in further development. “Obviously [pharmaceutical companies] I don’t see it as a market worth the research and development costs,” says Taylor.

What are the risks of injecting gray-market peptides?

The FDA warns that they pose “serious safety risks,” including allergic reactions. The federal agency has banned their production by American pharmacies, although their personal use is legal.

The risks of injecting gray market peptides start with their lack of precision. These substances cannot be targeted to a specific area and can instead “activate pathways in tissues and systems that are actually detrimental to health,” says Taylor.

Since these proteins are associated with tissue growth, there is a risk that if you have early-stage cancer that you didn’t know existed, the peptides could accelerate its progression, he says.

Other risks include acromegaly, excess growth hormone that leads to problematic enlargement of bones, cartilage and organs. And botching a DIY injection can cause muscle paralysis, scarring and sepsis.

Additionally, “the chemically identical label is often misleading,” says Nitai Gelber, a Toronto-based sports medicine physician. A peptide may contain a part of protein that is chemically identical to something our bodies produce naturally, but “there are often other components that are also added to that molecule,” Gelber said, to aid absorption, its mechanism of action or to prevent degradation. These additions increase the risk of allergic or adverse reactions.

Anecdotally, Taylor has heard complaints from people linking their use of gray market peptides to rashes, numbness, and mood changes.

In July, two women were hospitalized with swollen tongues, breathing problems and elevated heart rates after peptide injections at an anti-aging festival in Las Vegas. The exact peptides involved are unknown.

How can people get them if they are banned in the United States?

Gray market peptides are typically sold online and labeled “for research purposes only” as a legal loophole.

Much of it comes from China, where imports of hormone and peptide compounds have increased dramatically: U.S. customs data shows they reached $328 million in the first three quarters of 2025, up from $164 million in the same period the previous year, the New York Times reported.

Some people source their peptides from “wellness clinics” in the United States that import and redistribute the substances, potentially advertising purity testing as a supplement to a safer supply.

But at this point, such promises don’t mean much. “People sign documents saying they understand the risks,” which absolves the provider of liability, Taylor says. As peptide research progresses slowly, “people are turning into guinea pigs or lab rats,” Taylor says.

Who is looking for them?

Gelber says he’s seen a big increase in interest from athletes and non-athletes, younger and older patients, although it’s mostly men and teenagers looking for a more muscular physique. “Over the last year, it’s been non-stop,” he says of patients asking him about injectable peptides, which rarely came up until 2023, he says.

Dr. Avinish Reddy, a longevity-focused concierge physician based in Los Angeles, notes a similar increase in interest. “It has become very common for patients to tell me that they have friends who take a certain peptide and that they swear by it,” he says.

Both doctors believe that social media promoting unrealistic body aesthetics, hype from influencers such as Gary Brecka and Joe Rogan, and frustration with the slow healing of conventional injuries are factors behind interest in the products.

When patients come to Reddy and Gelber using gray market peptides, both doctors recommend they stop and offer risk-reduction tips for those who won’t. “If you’re using something experimental, your doctor needs to know so that side effects aren’t missed or blamed on the wrong thing,” Reddy says.

Additionally, he advises them to watch for warning signs. “If you develop fever, injection site reactions, chest symptoms, or new neurological symptoms, stop immediately and seek medical attention,” he says. He also warns against stacking multiple experimental products, which makes it “much harder to know what helps or harms you.”

Injuries are often best managed through proper diagnosis, rehabilitation, training, sleep and nutrition, Reddy says. The dubious promise of peptides as cure-all supersubstances may distract patients from the fundamentals of long-term care.