Please Do Not Buy Peptides Online
Injectable peptides like Ozempic and Wegovy have surged in popularity, with at least one million Canadians using them to manage weight and type-2 diabetes. But while these drugs are prescribed by doctors to treat a narrow range of conditions, you don’t have to look very far to find a plethora of non-authorized peptide products available for purchase. They promise a range of benefits—including weight loss, muscle-building, overall longevity and more—and they’re often targeted to women aged 40+.
In August 2025, Health Canada issued a warning about unauthorized peptide drugs sold online—including injectable peptides, citing concerns over safety, efficacy and quality due to their lack of proper evaluation. Then, in April 2026, it issued another public advisory about unauthorized peptide use that said, in short, "do not buy or use these products."
Over the past year, the health authority has seized hundreds of unauthorized products from various online distributors and clinics. But these crackdowns haven’t quelled the frenzy for them.
On TikTok, videos abound featuring users injecting themselves with peptides and taking peptide-infused supplement stacks. On Instagram, charts abound highlighting the best peptides for every concern, from better sex to better skin. Prominent voices with huge platforms, including Joe Rogan and neuroscientist-turned-podcaster Andrew Huberman, openly discuss using peptides like BPC-157 and sermorelin, adding a veneer of legitimacy to the craze.
"There's always a kernel of truth in these claims, but it gets so wildly overstated that it stops being true,” explains Dr. Sandy Van, a Toronto-based obesity physician. Chatelaine asked Van and Timothy Caulfield, a science disinformation expert and University of Alberta professor, to break down the science—and the bunk—surrounding peptides.
What are peptides, exactly?
Peptides are short chains of amino acids that naturally occur in human bodies, as well as in food. They act as messengers, regulating essential processes like metabolism, immune responses and tissue repair.
There are thousands of different types of peptides—both natural and synthetic—including hormones, enzymes, antibodies and structural molecules like collagen. Insulin, one of the most popular peptides, has been crucial for managing diabetes since its synthesis in the 1920s.
“In the context of weight management, the most notable peptides are GLP-1 and GIP,” says Van. GLP-1 agonists such as semaglutide (marketed as Ozempic and Wegovy) and tirzepatide (marketed as Mounjaro and Zepbound) improve appetite regulation and blood sugar regulation, making them effective tools for weight loss.
What are peptides supposed to do?
Medically authorized peptides are widely prescribed to treat diabetes, obesity and a shortlist of tightly defined disorders like hypoparathyroidism, myasthenia gravis and certain immunodeficiency conditions. Peptides are complex molecules and require years of clinical testing to ensure safety and efficacy, so they’re typically approved for narrow, highly specific uses—not as catch-all cures.
The most substantiated clinical success remains GLP-1. “Semaglutide trials show an average of 15 to 20 percent weight loss,” says Van. Still, some of her patients walk away disappointed—even after losing, say, 16 percent of their body weight—because they’ve been primed by social media to expect far more. “They see these stories online of people claiming they lost 30, 40 even 50 percent [of their body weight],” she says. “It completely distorts their sense of what success looks like.”
Caulfield calls GLP-1 drugs “ game-changing.” Emerging research shows potential applications in treating cardiovascular diseases, Alzheimer's and Parkinson's. But this success has also fuelled overhype.
“People see the excitement around GLP-1s, and then an influencer will reference that peptide language and presto—it gives the impression that [peptides will be] just as revolutionary for them,” says Caulfield. Aside from dramatic weight loss, social media users claim a wide range of purported benefits from various peptide products, including substantial muscle growth, menopause relief and improved libido. Growth hormone-releasing peptides like sermorelin, praised by Huberman for improving sleep quality and muscle recovery, have gained traction among gym buffs, despite limited clinical evidence.
“Often influencers point to real research, but that study could be very preliminary and hasn’t been verified in a solid clinical trial,” Caulfield says. He describes this phenomenon as “scienceploitation”: leveraging legitimate, exciting research to market products that lack robust evidence.
Other users associate peptides with cognitive enhancement and improved immune responses, though evidence supporting these claims remains largely anecdotal or preliminary. In skincare, topical peptides are commonly advertised for stimulating collagen and elastin production, which improves skin hydration and elasticity, but more research is needed to support their efficacy.
How do you take peptides?
Peptides like semaglutide and tirzepatide are prescription-only medications administered via injection under medical supervision. These peptides have undergone rigorous testing, clinical trials and regulatory scrutiny over many years before reaching patients.
However, the online peptide marketplace has expanded dramatically with unregulated supplements sold as powders, capsules, sprays and injection kits available directly to consumers. These products typically carry claims of muscle gain, fat loss and anti-aging benefits, often employing scientific language to convey legitimacy without clear evidence. “When people see science-y words, it makes products feel more legitimate,” says Caulfield. “It's an effective marketing strategy, unfortunately.”
Do peptides really work?
Clinically validated peptides, particularly GLP-1s, undeniably offer genuine benefits in controlled medical contexts. But the broad claims circulating in wellness and anti-aging spaces often lack scientific backing.
Influencers tend to cite early-stage research to support their peptide claims, but these studies rarely translate into real-world benefits.
“Only about 10 percent of phase-one trials ever make it to the clinic,” says Caulfield. “If a person references an animal study or a phase-one clinical trial, that should not be taken as proof that it works.”
At their best, medically supervised peptides offer tangible, evidence-backed benefits for conditions like obesity and diabetes. At their worst—aside from being a waste of money—unauthorized peptides are unproven and potentially dangerous products. They may trigger infections, allergic reactions or interactions with other medications. In the face of all this, Caulfield's advice is direct: “Be skeptical, especially if it's a direct-to-consumer product. Ask your healthcare provider what the science says.”
Ultimately, the hype surrounding peptides highlights societal anxieties and the relentless pursuit of shortcuts to health and longevity. “The internet is loud,” Caulfield notes, “but science is steady.”
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Alyanna Denise Chua is a writer and editor based in Toronto. She has written for Maclean’s, Toronto Life, the Globe and Mail and other publications.
