Doctors have fielded scattered reports of hair loss from patients on GLP-1 weight-loss and diabetes drugs for several years, but the evidence linking the two has mostly been anecdotal. A study published Sept. 3 in the Journal of Investigative Dermatology offers the first genetic evidence for the connection, at least in men.
Researchers at NYU Grossman School of Medicine, led by dermatology and population health researcher Lynn Petukhova, found that men who are already genetically predisposed to androgenetic alopecia, the most common inherited form of male-pattern baldness, face an added 7% risk of hair loss if they use GLP-1 receptor agonists such as semaglutide (sold as Ozempic and Wegovy) or tirzepatide (Zepbound), according to Medical Xpress.
The team used a technique called two-sample Mendelian randomization, which uses naturally occurring genetic variation as a proxy for drug exposure to estimate whether an association is likely to be causal rather than coincidental. Rather than tracking actual GLP-1 prescriptions, the researchers used variants in the GLP1R gene, which raises the body's own levels of GLP-1 receptor protein, as a stand-in for GLP-1 drug activity. They then checked how often those variants overlapped with genetic markers for androgenetic alopecia across two large datasets: the eQTLGen consortium, covering 31,684 people, and a separate complex-traits genetics dataset of 205,327 mostly white men.
The 7% added risk held up even after the researchers adjusted for hypertension, insulin resistance and testosterone levels, three factors that independently affect both metabolic health and hair loss.
Our study provides the first genetic link between GLP-1 use and an increased risk of male-pattern hair loss.
Lynn Petukhova, Ph.D., NYU Grossman School of Medicine
The finding matters because GLP-1 drugs are now used by millions of people for diabetes and obesity, and hair thinning has been one of the more common side-effect complaints, often attributed simply to rapid weight loss rather than to the drug itself. A genetic association study like this one cannot prove that the drugs directly cause hair follicles to fail; Mendelian randomization is designed to approximate a controlled experiment using genetic data, but it is not a clinical trial, and the researchers say more work is needed to pin down the underlying biology connecting GLP-1 receptor activity to hair follicle health.
The analysis was also limited to men, since androgenetic alopecia genetics are far better characterized in men than in women, so it remains unclear whether a similar risk applies to women taking the same drugs. NYU Langone co-investigators Jerry Shapiro and Kristen Lo Sicco, both dermatologists, were also involved in the work, which was funded by grants from the National Institutes of Health.
For now, the researchers say the takeaway for patients is not to stop a GLP-1 medication over hair-loss worries without talking to a doctor, since the drugs' benefits for diabetes and obesity are well established, while the hair-loss risk identified here is modest and concentrated in people already genetically susceptible. The team says its next step is investigating what mechanism might connect GLP-1 receptor signaling to hair follicle biology.
