Brazilian survey finds 23.8% of GLP-1 users took semaglutide or liraglutide without a prescription

A web-based survey of 860 adults in Brazil who used GLP-1 receptor agonists for weight loss found that 23.8 percent reported using the drugs without a medical prescription, according to a study published in the International Journal of Obesity ^[1]. The authors write that the findings may help support public measures aimed at reducing the practice ^[1].

The survey ran from November 2024 through April 2025 and was spread through posts and paid advertisements on WhatsApp, Instagram, TikTok, YouTube and Facebook, along with QR codes printed on materials placed in public and clinical settings ^[1]. To take part, people had to be 18 or older, live in Brazil, and report current or past use of liraglutide or semaglutide for weight loss — the only GLP-1 receptor agonists approved in Brazil for overweight and obesity when the data were collected ^[1]. The group's mean age was 39.46 years, 82.0 percent were female, and 47.1 percent had obesity ^[1]. All information was self-reported ^[1].

The study reports a self-medication proportion of 23.8 percent, with a 95 percent confidence interval of 21.1 to 26.8 percent ^[1].

Several characteristics were linked to higher rates of using the drugs without a prescription: not having obesity (prevalence ratio 1.45, 95 percent CI 1.13–1.89), not attending physical training centers (PR 1.55, 95 percent CI 1.23–1.96), and working in a healthcare-related profession (PR 1.45, 95 percent CI 1.14–1.84) ^[1]. Lower rates were associated with being married (PR 0.73, 95 percent CI 0.57–0.94), having diabetes (PR 0.35, 95 percent CI 0.18–0.70), and having eating disorders (PR 0.72, 95 percent CI 0.34–0.97), though the confidence interval on the eating-disorder finding was wide ^[1].

Because participants volunteered through an online questionnaire, the 23.8 percent figure is not a national prevalence estimate for Brazil, and the study did not measure use in the United States ^[1]. The authors say they used paid promotion and geographically targeted advertising to widen reach and limit selection bias, but the sample remained self-selected ^[1].

The researchers note that Brazil has strict rules on selling GLP-1 drugs for individual use, but that pharmacies were not required to keep prescriptions on file until 2025 ^[1]. The paper also cites US Food and Drug Administration warnings about counterfeit Ozempic (semaglutide) in the US supply chain and about unapproved GLP-1 drugs sold for weight loss, plus a UK statement on hospital admissions and deaths tied to inappropriate use ^[1].

Why it matters for patients

GLP-1 medications — semaglutide (sold as Ozempic, Wegovy and Rybelsus) and liraglutide — are prescription drugs, and the study's focus is people who obtained them without a prescription or clinical supervision ^[1]. The authors describe self-medication as potentially harmful and associated with the risk of serious adverse events ^[1].

The pattern in the survey may be familiar to US readers. Self-medication was more common among people who did not have obesity, which is outside the approved use of these drugs for weight loss; the study notes they are approved for people with a body mass index of 30 or higher, or 27 to 29.9 with weight-related conditions ^[1]. The authors also write that self-medication can worsen body image disorders and may be driven by them ^[1].

Counterfeit and unapproved versions are a separate safety concern. The study cites FDA statements warning consumers about counterfeit Ozempic found in the US supply chain and about unapproved GLP-1 drugs used for weight loss ^[1]. How often unsupervised use happens in the United States has not been reported in this study.

What happens next

Brazil's health regulator, ANVISA, moved in 2025 to require pharmacies to retain GLP-1 prescriptions, a rule the study points to as part of the regulatory backdrop for its findings ^[1]. Whether that change lowers self-medication rates has not been reported. The study includes no follow-up data on what happened to participants after they answered the questionnaire ^[1].