A multinational study has found that people taking GLP-1 medications for weight loss and diabetes reported significantly higher rates of hair loss and nail detachment than those who had never used the drugs.
The research, conducted with contributions from dermatologists Dr. Maria Bianca Piraccini, Dr. Bruno Halioua and Dr. Sergio Vañó-Galván, alongside physician Dr. Charles Taïeb, was presented at the European Academy of Dermatology and Venereology (EADV) Congress 2026 in Vienna, Austria. Supported by French dermatological laboratory Ducray, the study compared 575 GLP-1 users with 1,329 non-users with obesity, type 2 diabetes, or both, across France, the United States, Brazil, and Mexico.
Researchers found that 39.3% of GLP-1 users reported nail detachment, compared with 8.7% of non-users, making the condition approximately 4.5 times as common among those taking the medications. Nail detachment, medically known as onycholysis, occurs when a fingernail or toenail separates from the underlying nail bed.
Hair loss was also more frequently reported among GLP-1 users. About 50% reported unusual hair shedding, compared with 34% of non-users. Reduced hair volume or density affected 42% of users versus 19% of non-users, while hair loss beginning after treatment started was reported by 26% of users compared with 12% of controls.
Overall, 66.3% of GLP-1 users reported at least one nail disorder, including discoloration, brittleness, and ridges, compared with 52.8% of non-users.
GLP-1-based medications include semaglutide and tirzepatide, which are used to manage type 2 diabetes and obesity. These medications help regulate blood sugar and reduce appetite, although tirzepatide acts on both GIP and GLP-1 receptors. The study did not establish separate risks for individual medications.
Researchers suggested that rapid weight loss, reduced food intake, and possible nutritional deficiencies could contribute to the reported changes. However, the study relied on self-reported symptoms collected at a single point in time and could not establish that the medications directly caused the conditions. About half of GLP-1 users reported nail problems before starting treatment.
