Adults with type 2 diabetes taking GLP-1 drugs showed a 37% higher risk of clinically recorded non-scarring alopecia than SGLT-2 inhibitor users and a 68% higher risk than DPP-4 inhibitor users.
12,004 GLP-1 users were compared with 15,221 SGLT-2 users, and 11,964 GLP-1 users with 11,238 DPP-4 users, using Penn Medicine records from 2019 to 2024.
Six to seven per 1,000 GLP-1 users experienced hair loss annually, suggesting the absolute risk is low even as the association was consistent across comparator drugs.
Researchers and outside clinicians said the observational study does not prove causation, but rapid weight loss, calorie restriction, nutrient deficiencies and thyroid-related changes could help explain the shedding.
Doctors said most cases are likely temporary and advised patients not to stop GLP-1 treatment without medical guidance, instead monitoring protein, iron, zinc and other nutritional factors.