GLP-1 users report more nail detachment, hair loss than nonusers, study finds

Patients taking GLP-1 receptor agonists were more than four times as likely to report nail detachment as similar patients who had never used the drugs, according to a multinational study presented at the European Academy of Dermatol

ogy and Venereology (EADV) Congress 2026.

The study found that 39% of GLP-1 users reported nail detachment compared with 9% of controls, while two-thirds (66%) experienced at least one nail disorder, compared with 53% of controls. A companion study drawing on the same participants found that hair loss and scalp changes were also significantly more common among users.

GLP-1 receptor agonists are increasingly used to treat type 2 diabetes and obesity, but their potential effects on nail health have remained largely unexplored, according to the researchers, with previous evidence limited to isolated adverse-event reports. The new data add dermatologic changes to the range of side effects physicians may find themselves discussing with patients on the drugs.

Researchers compared 575 GLP-1 receptor agonist users with 1,329 people with type 2 diabetes, obesity or both who had never taken the drugs. Participants were recruited across France, the United States, Brazil and Mexico.

Beyond nail detachment, nail discoloration was substantially more common among GLP-1 users, affecting 46% compared with 17% of controls.

Weight loss alone did not appear to explain the increased prevalence of nail problems, the researchers reported. Differences between GLP-1 users and controls remained significant when the analysis focused specifically on participants who had lost weight.

“Until now, nail changes associated with GLP-1 therapies had essentially been anecdotal,” said study author Charles Taïeb. “Our findings show a clear association, but they also underline an important point: not everything that happens during GLP-1 treatment is necessarily caused by the treatment itself.”

The researchers cautioned that the study cannot establish that GLP-1 receptor agonists caused the nail changes. About half of users reported experiencing nail problems before starting treatment, and adjusting for dermatological conditions and nutritional deficiencies reduced the strength of some associations. Even after adjustment, however, nail detachment and discoloration remained about two to three times more frequent among users.

Hair and scalp changes

In the companion study, unusual hair loss was reported by 50% of GLP-1 users compared with 34% of controls, while loss of hair volume or density affected 42% versus 19%. Hair loss that began after treatment initiation was more than twice as common among users (26% vs. 12%), and scalp redness was about three times more frequent.

Hair loss among GLP-1 users rarely occurred in isolation, according to the researchers. In the majority of cases, it was accompanied by scalp symptoms such as itching, redness or scaling.

“This suggests that what is happening on the scalp may go beyond the classical shedding seen after rapid weight loss and involve an inflammatory component,” said study author Bruno Halioua. “Scalp inflammation was the rule rather than the exception, which clinicians do not currently look for and which may be treatable. Taken together, our findings suggest that factors beyond weight loss alone may contribute to the hair, scalp and nail changes observed among GLP-1 users.”

Halioua said the findings should give patients awareness rather than cause alarm.

“These changes are frequent, usually benign, and are not a reason to stop an effective treatment on one’s own initiative,” he said. “Anyone who notices hair shedding, an itchy or red scalp or nail changes should mention it to their doctor rather than discontinue therapy.”

Limitations and next steps

Both studies were cross-sectional and relied on patient-reported symptoms, meaning they can identify associations but cannot establish that GLP-1 treatment caused the changes.

The researchers now plan prospective research that will follow patients from the start of treatment, using standardized dermatological examinations and biological monitoring to determine when the changes develop, why they occur and whether they are reversible.