Wegovy and Mounjaro linked to up to 70% higher hair loss risk

A study by researchers at the University of Pennsylvania examined more than 50,000 health records and found that users of GLP‑1 weight‑loss medications—semaglutide (marketed as Wegovy) and tirzepatide (Mounjaro)—experienced a significantly higher likelihood of alopecia. Compared with patients taking DPP‑4 inhibitors, the GLP‑1 group had a 68 % higher risk of hair loss; compared with those on SGLT‑2 inhibitors, the risk was 37 % higher. Overall, the analysis suggests up to a 70 % increase in hair‑loss incidence, typically emerging about one year after treatment begins. The effect was observed in both men and women, with a stronger signal among women. Data from the UK Medicines Agency recorded 940 reports of hair loss linked to tirzepatide and 312 linked to semaglutide since early 2025. The U.S. Food and Drug Administration has been notified of these findings and is evaluating the safety signal.