The study included 575 people who used GLP-1 medications and 1,329 people with obesity and/or type 2 diabetes who had never taken the drugs. Participants were from France, the United States, Brazil and Mexico.
The findings were presented at the European Academy of Dermatology and Venereology Congress 2026, according to The Sun.
GLP-1 medications are already known to cause side effects such as nausea, vomiting, diarrhea and constipation. The new research instead examined changes to the hair, scalp and nails.
Hair and scalp
Researchers found unusual hair loss in 50 percent of users, compared with 34 percent in the control group.
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At the same time, 42 percent experienced reduced hair volume, compared with 19 percent among people who did not use the medications.
Scalp redness was also three times as common among GLP-1 users. Many of those experiencing hair loss also reported itching, redness or a flaky scalp.
The researchers stress that the findings do not prove that the medications directly cause these problems.
Nail problems draw attention
The biggest difference involved the nails. Among GLP-1 users, 66 percent experienced at least one nail problem, compared with 53 percent in the control group.
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Nearly 40 percent of users experienced a nail separating from the nail bed. Among people who did not use the medications, the figure was just 9 percent.
Discolored nails were also reported in 46 percent of users, compared with 17 percent in the control group.
The researchers found these differences even when they looked only at participants who had lost weight.
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This article is made and published by Ida-Marie Palm Varbæk, who may have used AI in the preparation.