New research has linked GLP-1 weight-loss drugs to nail and hair problems. Here is what the science actually shows.

Two studies presented October 1 at the EADV Congress 2026 in Vienna tracked 575 GLP-1 users and 1,329 similar non-users in France, the US, Brazil and Mexico. Nail detachment was reported by 39 percent of users versus 9 percent of controls; discoloration by 46 percent versus 17 percent.

On hair, 50 percent of users reported unusual hair loss versus 34 percent of non-users, with volume loss at 42 percent versus 19 percent. Scalp redness was about three times as common.

The striking finding is that weight loss alone did not explain the differences. Researchers point to reduced nutrient intake, possible iron, zinc and biotin deficiencies, and scalp inflammation as contributors.

Context matters. These changes do not appear in the current US prescribing information for Ozempic, Wegovy, Mounjaro or Zepbound, and experts say hair shedding after rapid weight loss is often temporary.

Doctors advise patients not to stop the medication over nail changes alone, but to report any new hair, scalp or nail symptoms so causes can be checked.