Allure has written up a new study presented at the European Academy of Dermatology and Venereology Congress 2026 that found nail disorders reported far more often among people taking GLP-1 receptor agonists than among people who had never used them.

The drugs in question are semaglutide (sold as Ozempic and Wegovy) and tirzepatide (Mounjaro and Zepbound). The headline complication is onycholysis, which the Cleveland Clinic defines as the nail separating from the nail bed, and which nobody had looked at systematically before now.

The numbers

Researchers compared 575 GLP-1 users in the United States, France, Brazil and Mexico with 1,329 people who had type 2 diabetes or obesity and had never taken the drugs. Sixty-six percent of users reported at least one nail disorder, a 13% uptick over the comparison group, with nail detachment in 39% of users versus 9% of controls and discoloration in 46% versus 17%.

Those are large gaps, and the most interesting detail is buried further down: the increase held regardless of how much weight a person lost. That is the finding that separates this from the usual rapid-weight-loss story, though the authors say more research is needed.

Why nails and not just hair

Dermatologist Ife J. Rodney told Allure the result is "not surprising," comparing it to the hair shedding already associated with GLP-1 use. Nails and hair are both mostly keratin, and protein intake often drops when appetite does.

Doctors quoted in the piece point to nutrition rather than toxicity. Rodney said the body "may not produce nail plates as efficiently" during nutritional deficiency, and Mir Ali, medical director of a surgical weight loss center in California, said he sees the same thing in bariatric surgery patients.

Limitations

The study found an association, not causation, and the authors say so explicitly. Co-author Charles Taieb put it bluntly in a statement: the findings show a clear association, but "not everything that happens during GLP-1 treatment is necessarily caused by the treatment itself."

Nail detachment also has other causes, including tetracycline, oral retinoids and thyroid disease, which is why Rodney argues the symptom needs a diagnosis rather than an assumption.

The question still open

Whether the drugs act on nail tissue independently of weight loss is the thing this data gestures at and cannot settle. Until someone runs a study designed to answer it, the association is real and the mechanism is a hypothesis.