Hundreds of people in the UK have reported hair loss after taking blockbuster weight loss drugs Mounjaro, Ozempic and Wegovy, new figures show — as a major study confirms the link. So far in 2026, the Medicines and Healthcare products Regulatory Agency (MHRA) has received 399 reports of hair loss relating to tirzepatide (Mounjaro), alongside 541 last year. For semaglutide (Wegovy and Ozempic), the agency has recorded 148 reports this year and 164 in 2025.
The fresh data comes as researchers publishing in the British Medical Journal (BMJ) found that people on GLP-1 receptor agonists face a significantly higher risk of alopecia than those taking other diabetes drugs. The team analysed electronic patient records from the University of Pennsylvania Health System, comparing outcomes for around 50,000 adults.
“Study of 50,000 people finds weight loss drugs Mounjaro, Ozempic, Wegovy increase hair loss risk by up to 68%”
After adjusting for factors such as age and weight, they found that using GLP-1 drugs was associated with a 37% higher risk of hair loss than use of SGLT-2 inhibitors, and a 68% higher risk than use of DPP-4 inhibitors. Further analysis suggested the link related to non-scarring alopecia, where hair follicles remain intact and hair can potentially regrow.
The researchers noted that the US Food and Drug Administration (FDA) is already evaluating this potential safety signal, following case reports of hair loss after starting semaglutide and tirzepatide. They wrote that although hair loss does not typically cause physical harm, it may have significant psychosocial consequences, affecting self-esteem, quality of life and adherence to treatment.
On the reasons why people may lose their hair, the team said the “most likely mechanism” relates to weight loss and reduced caloric intake, which can lead to micronutrient deficiencies in iron, zinc and biotin that disrupt the hair growth cycle. Other possible factors include the metabolic, hormonal and immunological effects attributed to GLP-1 receptor agonists.
The study underscores a growing concern over the side effects of these increasingly popular drugs, which have been hailed as game-changers for obesity and diabetes. For patients already grappling with the stigma of weight, the prospect of hair loss could be an added burden — one that the researchers warn may affect whether they stay on treatment.