The surge in peptide use within the fitness world is pushing the conversation beyond gym culture and wellness circles into the mainstream.Thanumporn Thongkongkaew/Getty Images
Longevity influencers and biohackers often tout peptides as a miracle cure for fat loss, muscle building and better sleep. There are peptides for skin care, inflammation and cognitive improvement. You can buy peptides promising improved energy, hormone regulation, or even a better tan. Basically, if you can think of a health problem, someone online is probably trying to sell you a peptide for it.
When people say they’re trying out peptides, it’s sort of like saying they’re trying out medicine. The term might be unfamiliar, but you’ve likely come across peptides in one form or another. GLP-1 prescription drugs such as Ozempic and Wegovy are peptides. Insulin is also a peptide. But beyond all regulated medications, there’s growing interest in compounds sold on the black and grey markets online.
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A simple Google search brings up dozens of websites selling peptides as “research chemicals” that promise everything from anti-aging to faster recovery and improved body composition. Many of these websites are promoted by internet personalities who earn commissions if their followers buy from them. They also purchase targeted ads aimed at health and fitness communities, and curious outsiders.
The surge in peptide use within the fitness world is pushing the conversation beyond gym culture and wellness circles into the mainstream. Below, we chatted with some experts to give you the basics on what peptides are, why they’ve entered the cultural conversation and whether or not they’re safe to try out.
What are peptides anyway?
Peptides are short chains of amino acids that are building blocks for proteins in your body. Some peptides help regulate processes such as immune response, cell growth and hormone signalling.
While peptides occur naturally, it’s relatively easy to create synthetic peptides in labs. Most therapeutic peptides are sold to consumers as injectables, though some are formulated as creams, pills or nasal sprays.
Why have peptides become so popular?
Part of the answer lies in new research – and part in marketing. Grand View Research, a research and consulting company, estimated the American therapeutic peptide market generated US$65.1-billion in 2024. It’s expected to reach US$160.3-billion by 2030. There is a lot of hype over peptides and their potential health and aesthetic benefits, but experts suggest taking that excitement with a grain of salt.
“As somebody who understands what peptides are at the molecular level, there’s nothing magical about them,” said Jonathan Jarry, a science communicator for McGill University’s Office for Science and Society who holds a master’s degree in molecular biology.
According to Jarry, the runaway success of Ozempic has many people jumping to conclusions about the potential of the compounds in general. “Just because one peptide works really well for one specific application does not mean that every peptide will work for any kind of indication.”
That’s not the message dominating social media. Instead, peptides such as BPC‑157 and TB‑500 (dubbed the Wolverine Stack, named for the superhero’s healing abilities) or retatrutide (a favourite among bodybuilders for supposedly helping to burn fat while holding onto muscle better than other GLP-1 medications) are promoted as “game changers.” Peptides are often championed as cheat codes to a jacked and toned physique, ignoring the fact that black-market compounds are unregulated drugs bought from unregulated sources and injected into your body.
“A lot of these peptides were studied and abandoned for failing to show benefits or for having really bad side effects,” said Jarry. He notes that if drug companies had the evidence to get a licence for these peptides and make a lot of money, it’s something they would have chased. But the research wasn’t there.
According to Dr. Stuart Phillips, a professor of kinesiology at McMaster University and one of the world’s most cited researchers on skeletal muscle health and nutrition, another major reason peptides have become so popular is the growing anti-aging market.
“I think the latest craze has been fuelled by the longevity market,” said Phillips. He sees peptides as part of a larger societal shift toward preventative and personalized health care, with a focus on anti-aging and health span, optimizing people’s “healthy” years in terms of mobility and cognitive function rather than just trying to live longer.
Ironically, some of the people most concerned with longevity may also be the most willing to take bigger risks – and spend more money – with questionable treatments marketed as cutting edge.
Are peptides safe to use? And do they work?
Peptides prescribed by doctors are backed by clinical research. GLP-1s can help with weight loss and treat diabetes. Oxytocin is a peptide that has been used to induce labour.
But unregulated peptides carry significant risks.
Even if some compounds eventually become regulated (U.S. Secretary of Health and Human Services Robert F. Kennedy Jr. has discussed loosening restrictions on 14 peptides previously prohibited by the FDA), buying black-market drugs online means there is no guarantee that the chemicals are actually what they say they are.
Dosage can be difficult to determine without the supervision of a medical professional. There are also risks around side effects including hormonal and metabolic problems, cancer and infections of injection sites. “I don’t want to say completely junk them, but what I’m really pushing hard on is we just need trial data,” said Phillips.
Anecdotal evidence from people experimenting on themselves is not the same as saying that the benefits of any given peptide are established as facts.
