PARIS — A large new analysis of data has shown that GLP-1 receptor agonists (RAs) are associated with a high risk for several types of hair loss, according to data presented at the European Academy of Dermatology and Venereology (EADV) 2025 Congress. But this phenomenon could be more of an unmasking than a direct effect of these drugs.

In the retrospective cohort study, which used data from the TriNetX US Collaborative Network, GLP-1 RA use was independently associated not only with an increased incidence of telogen effluvium (TE), but also with increased incidence of androgenic alopecia (AGA) and nonscarring hair loss in general. However, no association with alopecia areata (AA) was seen.

Increasingly Used Drugs

GLP-1 RAs are increasingly being used in clinical practice for various reasons, said the study’s presenting author Yagiz Matthew Akiska. “Their metabolic and cardiovascular benefits are at this point pretty well established,” he said. Akiska is a fourth-year medical student at George Washington University School of Medicine and Health Sciences in Washington, DC. 

“However, as their prescribing expands, we are seeing more and more unexpected side effects being reported in the literature. One of the most interesting ones that we are seeing is hair loss, specifically nonscarring hair loss,” he added. 

Most of these reports are limited to small cohorts of patients or to pharmacovigilance reports, Akiska said, “leaving uncertainty about the true risk and clinical relevance of hair loss in patients using GLP-1 RAs.” 

Risk Re-Examined

Together with his mentor Adam Friedman, MD, and others at George Washington University, Akiska set out to examine what the risk for different types of hair loss GLP-1 RAs might entail. To create the study population, the team examined data on adult patients aged 18-89 years who had filled at least two prescriptions for a GLP-1 RA and had at least two health visits between 2014 and 2024. 

Specifically, they looked for patients who had been treated with liraglutide (Saxenda and others), semaglutide (Ozempic/Wegovy), dulaglutide (Trulicity), exenatide (Byetta and others), lixisenatide (Lyxumia/Adlyxin), and tirzepatide (Monjaro/Zepbound) and who did not have a history of prior hair loss or other causes for hair loss. These causes included scarring alopecia, thyroid disease, ovarian dysfunction, menopause, malnutrition, chemotherapy, connective tissue disease, bariatric surgery, and trichotillomania.

Overall, they found 590,597 patients who had been prescribed GLP-1 RAs and 4,550,239 who had not. Propensity score matching was then used to adjust for age, sex, race/ethnicity, BMI, and type 2 diabetes mellitus and create two comparable groups of patients who could be studied. Overall, there were 547,993 GLP-1 RA users and 547,993 GLP-1 RA nonusers in the analysis. 

Main Outcomes

Over the 10-year period within which data were obtained, the incidences of TE, AGA, and nonscarring hair loss all increased to a greater extent in the GLP-1 RA users than in nonusers. Nonscarring hair loss was defined as a composite measure of TE, AGA, and AA. 

The researchers used logistic regression to calculate adjusted odds ratios (ORs) for experiencing the different hair loss categories at 6 and 12 months. 

At 6 months, GLP-1 RA use was associated with a significant 26% increased chance of nonscarring hair loss and a 62% increased chance of developing AGA (ORs vs nonuse were 1.26 and 1.62, respectively; both P < .0001). While the OR for TE was 1.30, suggesting a 30% increased risk for TE after 6 months of GLP1 RA use vs nonuse, this result was not significant (P = .18).

At 12 months, however, the chances of developing TE were a significant 76% higher with GLP-1 RA use than they were without, and the odds for having AGA and nonscarring hair loss were 64% and 40% higher, respectively (both P < .0001). 

The ORs for AA at 6 and 12 months were a nonsignificant 0.91 and 0.85, respectively. 

Clinical Significance

“As clinicians, we should recognize that hair shedding and hair loss is an emerging, real-world side effect of GLP-1 RAs,” Akiska said. 

“For many patients, hair loss becomes pretty important as a side effect, because they're also trying to lose weight, they're concerned about their appearance, they're trying to control their diabetes. On top of it, they're dealing potentially with hair loss, which can be very debilitating for them.”

Akiska added, “We should start thinking about more proactive strategies to mitigate these risks,” as well as counseling patients who are thinking of starting these drugs for weight loss or diabetes accordingly. 

Commenting on the findings for Medscape Medical News, Michael Buontempo, MD, a resident physician at Dartmouth-Hitchcock Medical Center in Lebanon, New Hampshire, said, “This real-world cohort likely reinforces what we’re seeing elsewhere, which is that most hair shedding on GLP-1s looks like androgenetic alopecia unmasked by an episode of telogen effluvium driven by the magnitude of weight loss, rather than a direct drug toxicity.”

Buontempo added, “Hair loss matters for quality of life and adherence, but it’s usually reversible. The best mitigation is pacing weight loss and maintaining nutrition rather than stopping effective therapy.”

Practice Impacts

According to Buontempo, some practice take-home messages would be around “counseling up front about temporary shedding. Set expectations on timing (it typically begins about 6-12 weeks after the trigger [ie, weight loss] and improves over about 3-6 months once weight stabilizes) and emphasize nutrition support rather than changing your prescribing when there’s a clear indication.”

Moreover, he noted that screening for and treating “co-contributors such as iron deficiency, low protein intake, and thyroid issues” were important, “and I warn that rapid weight loss can unmask underlying androgenetic alopecia, which may need standard AGA therapy.” 

In terms of prevention, Buontempo said that patients could be advised to “avoid very rapid loss; ensure a balanced diet; check ferritin/iron, B12, zinc, and vitamin D if shedding is prolonged; and consider topical or oral minoxidil if shedding doesn’t remit or if patterning suggests AGA.” 

The study was funded by the National Alopecia Areata Foundation. Akiska acknowledged a travel grant from the Foundation to attend the 2025 EADV Congress. Buontempo reported no relevant financial relationships. 

Sara Freeman is a freelance medical journalist based in London, England.