What are peptides and why are they all over traditional and social media?
Peptides are chains of molecules called amino acids that link together; they are smaller versions of proteins. Thousands of naturally occurring peptides have been identified in the human body. They perform a wide variety of biological functions, although scientists continue to discover new peptides and learn more about their roles. Many peptides act as signalling molecules, allowing cells to communicate with one another, while others are hormones that bind to receptors on cells and regulate processes such as appetite, metabolism, growth, inflammation and tissue repair. Insulin is widely recognized as the first peptide hormone to be isolated and became the first peptide drug used successfully in modern medicine.
Why does it feel like they are suddenly everywhere? Between advertising and marketing campaigns, celebrity endorsements and social media, peptides are having a moment. Ozempic, a semaglutide used to treat diabetes, hit the market in 2017, following approval by the U.S. Food and Drug Administration (FDA). Health Canada and the European Medicines Agency approved it in 2018. Before semaglutide received formal approval for chronic weight management, some physicians were prescribing it off-label for obesity. In 2021, the FDA and Health Canada approved the higher-dose formulation (Wegovy) specifically for weight management. Since then, awareness has grown. Celebrities like Oprah Winfrey, Rosie O’Donnell and tennis star Serena Williams, and many others, have spoken openly about using semaglutides for weight loss. Semaglutide mimics a natural gut hormone named glucagon-like peptide-1 (GLP-1).
Hailey Bieber and Gwyneth Paltrow have launched skincare products that feature peptides to keep them and us looking young. Jennifer Aniston and Kate Hudson like to drink their peptides by adding collagen peptide supplements to their daily smoothies to keep their skin looking young and glowing.
Peptides have important functions in the body but, like stem cells, they are not a magic bullet for all that ails us. In the case of using collagen peptides for skincare, Joe Schwarcz, at McGill University’s Office for Science and Society, says their efficacy is “debatable.” He writes, “The contention is that once these are absorbed, they will assemble to produce of [sic] collagen in the skin. Evidence for this is sketchy, but in any case, collagen peptides are effective moisturizing agents so they can improve the appearance of the skin.”
Despite mild to sometimes serious side effects from taking GLP-1 medications for weight loss, they are approved medications with well-established safety profiles when prescribed appropriately. Likewise, collagen peptides are generally considered safe, although evidence for many of the cosmetic claims remains limited. You can read about the many uses of peptides in this WebMD article.
Peptides are being used in other ways that may have dangerous side effects. Dietary supplements* and other products marketed for fitness purposes may promise muscle growth and injury recovery, or make anti-aging claims. Not all of these wellness products are regulated or have completed the rigorous clinical testing required for authorized medications.
Health Canada is warning Canadians against injecting peptides bought online. Products labelled “For Research Use Only – Not for Human Consumption” are ones to watch for. “Unauthorized drug products are illegal in Canada and have not been assessed for safety, efficacy, and quality by Health Canada. They have not been demonstrated, through scientific trials, to provide the health benefits that they claim.
Consumers taking unauthorized peptide drugs are exposed to a variety of risks, including, but not limited to, hormonal imbalance, mood swings, blood sugar imbalance, liver or kidney damage, blood clots, and growth of cancerous tumours.”
Health Canada lists examples of unauthorized injectable peptide drugs, additional possible side effects, and what you should do if you have used one and feel unwell. Find more information on Health Canada’s website.
At the top of Health Canada’s list is BPC-157, a synthetic peptide originally isolated from human gastric juice that is popular among athletes. While BPC-157 has shown regenerative properties across animal models, human data are “extremely limited.” This means data regarding safety and associated side effects are also limited. In 2022, the World Anti-Doping Agency first banned BPC-157 under the S0 Non-Approved Substances category, prohibiting its use in both competition and training due to its lack of human clinical approval. It is still on the list, as of January 2026.
As interest in peptides continues to grow, it’s worth remembering that not all peptide products are created equal. Some are evidence-based medicines that have transformed patient care, while others remain unapproved products with little or no evidence of safety or effectiveness.
CBC’s The National went undercover to investigate the use of, and how to access, unauthorized peptides. Watch Idil Mussa’s report, which includes an interview with Timothy Caulfield, University of Alberta.
*People should exercise caution when taking any supplement and discuss the potential benefits and risks with a doctor beforehand.
Stacey Johnson
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