Study details

For the study, which was presented at the European Academy of Dermatology and Venerology's 2026 meeting, researchers recruited patients in France, the United States, Brazil, and Mexico. The study included 575 participants who used GLP-1s, and the researchers compared them to a control group of 1,329 participants with obesity and/or type 2 diabetes who had never used a GLP-1 drug.

Overall, the researchers found that 66.3% of GLP-1 users and 52.8% of non-users reported any type of nail disorder. Specifically, 39.3% of the GLP-1 users had onycholysis, which is the separation of fingernails or toenails, compared to 8.7% of those in the control group, which translated to a 4.5 times increased risk.

In addition, 45.6% of those in the GLP-1 group had dyschromia, or nail discoloration, compared to 17% of those in the control group, representing a 2.7 times increased risk. The researchers also found that nail fragility and presence of ridges or grooves were also more common among GLP-1 users.

After accounting for comorbidities, including any dermatologic conditions, an analysis still showed a nearly two- to threefold higher likelihood of onycholysis and dyschromia among GLP-1 users compared to nonusers.

Discussion

Bianca Maria Piraccini, one of the study's authors from University of Bologna in Italy, said the findings were unusual.

"After adjusting for age, sex, country, comorbidities and so on, we have a really high prevalence of onycholysis in patients undergoing GLP-1 receptor agonist treatment," she said. "This is quite unusual because onycholysis cannot be related to weight loss. Weight loss is commonly associated with nail plate surface abnormalities, which can be described as rough, uneven nails. Nail detachment is not a sign of low caloric intake or protein deficiency or other signs, so we think it could be directly related to the drug. This will prompt us to do more studies."

Charles Taieb, one of the study's authors from the European Market Maintenance Assessment in France, said the research is among the first large-scale analyses of the nail and hair effects of GLP-1s.

"Until now, nail changes associated with GLP-1 therapies had essentially been anecdotal," he said in a statement. "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."

Joe Tung, of the University of Pittsburgh Medical Center, said that while the study raises an interesting issue, it should be viewed cautiously.

However, sensitivity analyses accounting for patients with a history of nail problems before using the drugs continued to show a two- to four-fold difference in discoloration and separation among GLP-1 agonist users. At the same time, an analysis of new-onset nail lesions found no difference in nail detachment or discoloration between GLP-1 users and nonusers. Researchers said the true association likely falls between the study's adjusted and new-onset findings, meaning a drug-related effect remains possible.

Separately, Mir Ali, medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center, said that nail issues following weight loss isn't unheard of.

"This is uncommon overall, but we do see it with our surgical weight loss patients as well," Ali said. However, Ali agreed that nail detachment "seems to be independent of the weight lost" based on the study's findings and his personal experience with patients.

Ali added that people using GLP-1s often take in less calories than normal, which makes it difficult to meet thresholds for nutrients that support nail growth like protein, iron, and B vitamins.

"As a result, your body may not produce nail plates as efficiently or may even stop producing the nails temporarily," which leads to nail breakage and detachment, according to Ife Rodney, founding director of Eternal Dermatology + Aesthetics. "It's not that GLP-1s are directly toxic to the nails, but the body has other concerns outside the nails when you're in this state of nutritional deficiency."

According to Piraccini, the message of the study to clinicians is "don't forget to look at the nails and ask if [nail abnormalities] were present prior to starting the treatment or if the onset was during treatment. Look carefully at [affected nails] and try to correlate them to the drug. I think that a specific drug effect is possible and warrants confirmation."