New research has found significantly higher rates of nail detachment, discolouration among GLP-1 receptor agonist users, although researchers caution that the findings do not establish causation.
People taking GLP-1 receptor agonists are more than four times as likely to report nail detachment as those not using the drugs, according to new international research that also raises concerns about hair loss and scalp inflammation.
The findings, presented at the European Academy of Dermatology and Venereology (EADV) Congress 2026 in Vienna, suggested there was a need to pay closer attention to nail, hair, and scalp symptoms in patients using the diabetes and weight-loss treatments.
In the first controlled study to investigate the potential effects of GLP-1 receptor agonists on nail health, researchers compared 575 users with 1329 people with type 2 diabetes and/or obesity who had never taken the medications. Participants were recruited from France, the US, Brazil, and Mexico.
Nail detachment was reported by 39% of GLP-1 users compared with just 9% of controls, while nail discolouration affected 46% and 17%, respectively. Overall, two-thirds (66%) of GLP-1 users reported at least one nail disorder, compared with 53% of controls.
The increased prevalence of nail problems did not appear to be explained by weight loss alone, with significant differences persisting when researchers restricted their analysis to participants who had lost weight.
Study author Dr Charles Taieb said the findings provided the first controlled evidence of an association between GLP-1 therapies and nail disorders.
“Until now, nail changes associated with GLP-1 therapies had essentially been anecdotal,” he said.
“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 acknowledged several potential confounding factors, including pre-existing nail disorders and nutritional deficiencies.
Around half of GLP-1 users reported nail problems before starting treatment, while adjustment for dermatological conditions and nutritional deficiencies weakened some of the observed associations.
However, nail detachment and discolouration remained approximately two to three times more frequent among GLP-1 users after adjustment.
A companion study involving the same participants also identified significantly higher rates of hair loss and scalp symptoms among GLP-1 users.
Unusual hair loss was reported by 50% of users compared with 34% of controls, while loss of hair volume or density affected 42% versus 19%.
Hair loss beginning after treatment initiation was also more than twice as common among GLP-1 users, affecting 26% compared with 12% of controls.
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Researchers also found that scalp redness was approximately three times more frequent among GLP-1 users.
Importantly, hair loss among users rarely occurred in isolation, with most affected participants also reporting scalp symptoms such as itching, redness or scaling.
Study author Dr Bruno Halioua said the findings suggested the mechanisms underlying hair loss in GLP-1 users could be more complex than the telogen effluvium commonly associated with rapid weight loss.
“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,” he said.
“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.”
However, the researchers stressed that both studies were cross-sectional and relied on patient-reported symptoms, limiting their ability to establish whether GLP-1 treatment directly caused the changes.
The findings also do not establish whether particular GLP-1 medications, treatment durations or doses carried greater risks.
Dr Halioua said patients should be aware of the potential symptoms but should not discontinue treatment without medical advice.
“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.”
The researchers are now planning prospective studies that will follow patients from the beginning of GLP-1 treatment, incorporating standardised dermatological examinations and biological monitoring.
These studies will aim to determine when nail, hair, and scalp changes develop, investigate potential underlying mechanisms, and establish whether symptoms resolve over time or after treatment cessation.
Both studies were presented at the EADV Congress 2026, held in Vienna, Austria, from 30 September to 3 October.
