GLP-1 receptor agonists — a class of medications including semaglutide (Ozempic) and tirzepatide (Zepbound) — are widely prescribed for type 2 diabetes and obesity. In October 2026, two studies conducted by the SCOP-GLP1 research team and presented at the annual conference of the European Academy of Dermatology and Venereology added to the known side-effect profile of these drugs by examining hair and nail changes among users.
The studies each compared 575 people taking a GLP-1 for type 2 diabetes or obesity to 1,379 controls with these conditions who had not started GLP-1 therapy. Participants were selected from a representative sample across four countries: France, the United States, Brazil, and Mexico. The average length of tracked treatment was 18.5 months, and weight changes were monitored over a three-month period.
Regarding hair loss, roughly half of people on a GLP-1 reported "unusual hair loss" compared to a third of controls. GLP-1 users were also more likely to report scalp irritation. Importantly, researchers found that people's likelihood of scalp problems was not correlated with the amount of weight they lost, suggesting these hair issues are not entirely caused by weight loss while taking a GLP-1 — a long-known phenomenon that can trigger temporary hair loss during rapid weight reduction.
A recent study of GLP-1 receptor agonist users found that approximately 50% reported unusual hair loss, significantly higher than the 33% rate among non-users. The research suggests this may be related to factors beyond weight loss, as scalp problems did not correlate with weight reduction magnitude.
About 66% of GLP-1 users reported nail problems in general compared to 53% of non-users. The difference was more substantial for specific nail changes: roughly 39% of GLP-1 users reported nail detachment compared to 9% of controls, and 46% of people on GLP-1s reported nail discoloration compared to 17% of controls. The SCOP-GLP1 team noted that nail issues were often better explained by preexisting health problems, skin conditions, and nutritional deficiencies rather than the direct bodily effects of the drug itself.
Both studies remain preliminary. They were presented at a conference and have not yet undergone formal peer review. The researchers cautioned that their findings describe associations, not causes, and called for confirmation in prospective studies with clinical assessment. Study author Charles Taïeb, a clinical dermatologist at Necker University Hospital in Paris, emphasized that people taking or considering GLP-1 receptor agonists should not panic or stop treatment on their own because of hair or nail symptoms but should mention these symptoms to their doctor.
In practice, clinicians should look at the scalp for itching, redness, or scaling — not only at hair shedding — when starting or monitoring GLP-1 RA therapy. Nail changes should be interpreted in the context of the patient's overall health rather than automatically blamed on the drug, while persistent or progressive nail detachment deserves dermatological attention. Additionally, the U.S. Food and Drug Administration, following its own investigation of post-market data, now requires GLP-1 drugs like Ozempic (semaglutide) and Zepbound (tirzepatide) to list alopecia as a potential adverse reaction on their product labeling.
The research adds to the evolving understanding of GLP-1 medication side effects, highlighting that hair and nail changes may occur more frequently among users but likely reflect a complex interplay of factors rather than drug effect alone. Further prospective studies will be needed to determine causal relationships and whether such issues are reversible.