People taking GLP-1 medications for obesity or diabetes reported nail detachment and hair loss far more often than people with similar overall health who were not using the drugs, according to research presented on Oct. 1.

The findings came from two studies presented at the European Academy of Dermatology and Venereology Congress 2026 in Vienna, Austria. Researchers emphasized that the results show associations but do not prove the medications caused the reported conditions.

The studies evaluated 575 GLP-1 users and a control group of 1,329 nonusers. All participants had type 2 diabetes, obesity or both, and they were recruited across France, the U.S., Brazil and Mexico.

The primary study focused on nail health. Nail detachment was reported by 39% of GLP-1 users, compared with 9% of nonusers, making the condition more than four times as common among those taking the medications.

Nail discoloration was also considerably more frequent among drug users. It affected 46% of GLP-1 users, compared with 17% of participants in the control group.

Overall, 66% of people taking GLP-1 medications reported at least one nail disorder. That compared with 53% of people who were not taking the drugs.

Researchers found that weight loss alone did not account for the difference between the two groups. Even when the analysis was limited to people who had lost weight, those taking GLP-1 medications remained more likely to report nail problems.

After researchers adjusted for existing dermatological conditions and nutritional deficiencies, nail detachment and discoloration remained two to three times more frequent in the medication group.

“Until now, nail changes associated with GLP-1 therapies had essentially been anecdotal,” study author Dr. Charles Taïeb, a clinical dermatologist at Necker University Hospital in Paris, said in a press release.

“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.”

A second study examined hair and scalp conditions among the same group of participants. Unusual hair loss was reported by 50% of GLP-1 users, compared with 34% of people in the control group.

After treatment began, 26% of GLP-1 users reported hair loss or thinning. The same problems were reported by 12% of participants who were not taking the medications.

Loss of hair volume was also more common among GLP-1 users. It affected 42% of people taking the drugs, compared with 19% of nonusers, according to the study.

Scalp redness occurred about three times as frequently among GLP-1 users. Their hair loss was typically accompanied by inflammatory scalp symptoms, including itching, scaling or redness, the researchers reported.

“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 Dr. Bruno Halioua, a Paris dermatologist, in the release.

“Scalp inflammation was the rule rather than the exception, which clinicians do not currently look for and which may be treatable.”

Halioua advised patients experiencing these symptoms to consult a physician rather than stop taking their medication. He noted that the changes are typically not serious enough to justify discontinuing treatment.

Both studies relied on information reported by patients and examined participants at a single point in time. The authors said those limitations mean the findings can identify associations but cannot establish that GLP-1 medications caused the nail, hair or scalp changes.

The researchers also noted that roughly half of the surveyed GLP-1 users had experienced nail problems before beginning treatment. That finding further complicates efforts to determine what role, if any, the medications played.

The research team plans additional studies to determine when the changes occur, what may cause them and whether they disappear over time. The studies received institutional support from DUCRAY Laboratories, a division of the Pierre Fabre Group.

The reported findings leave researchers examining a notable pattern while stressing that patients should seek medical guidance rather than abandon treatment on their own.