EADV cohort reports increased hair loss incidence with GLP-1 drugs

Researchers from George Washington University and Children's National Hospital presented a real-world study at the European Academy of Dermatology and Venereology (EADV) congress showing that people taking GLP-1 receptor agonists had a higher risk of hair loss than similar people who did not take the drugs ^[1][2]. The study used the TriNetX US Collaborative Network, which pulls anonymized electronic health records from 67 US healthcare systems, and compared adults on GLP-1 drugs with matched controls from 2014 through 2024 ^[2].

The analysis included 547,993 matched adult GLP-1 users and controls, balanced for age, sex, race, BMI, and type 2 diabetes status ^[2]. Researchers tracked three types of nonscarring hair loss using medical billing codes: telogen effluvium (a stress-related shedding), androgenetic alopecia (pattern hair thinning), and alopecia areata (an autoimmune form causing patchy bald spots) ^[2].

At six months, people on GLP-1 drugs had 62% higher odds of androgenetic alopecia and 26% higher odds of nonscarring hair loss overall, compared with controls, both statistically significant ^[2]. Telogen effluvium was also more common at six months, but that difference was not statistically significant at that point ^[2]. By 12 months, all three outcomes were significantly more common among GLP-1 users: telogen effluvium risk was 76% higher, androgenetic alopecia 64% higher, and overall nonscarring hair loss 40% higher ^[2]. Researchers noted that incidence curves for GLP-1 users and controls began to diverge around 2019, with telogen effluvium and androgenetic alopecia rates splitting apart more sharply starting in 2021 to 2022 ^[2].

Importantly, alopecia areata — the autoimmune form of hair loss — was consistently more common in the control group, not in GLP-1 users, suggesting the drugs do not appear to trigger an autoimmune attack on hair follicles ^[2]. The authors pointed to other possible explanations for the hair loss they did find, including rapid weight loss itself, changes in insulin and insulin-like growth factor signaling, shifts in androgen levels, and direct effects of the drugs on hair follicles ^[2]. They noted these findings line up with earlier, smaller reports linking alopecia to semaglutide and tirzepatide specifically ^[2].

The study also looked at adolescents ages 12 to 17, but 10 or fewer pediatric GLP-1 users experienced any of the hair loss outcomes, which the authors said was too small a number to draw conclusions from ^[2].

Why it matters for patients

Hair shedding has been reported anecdotally by many people losing significant weight on GLP-1 drugs, and this study adds large-scale data suggesting the pattern is real and grows more pronounced the longer someone stays on the medication, at least out to 12 months ^[2]. Because the excess risk showed up for pattern thinning and stress-related shedding but not for the autoimmune type, the finding may ease concern that these drugs cause an immune attack on hair follicles ^[2]. This was an observational study built from insurance and medical record codes, not a controlled trial, so it can show an association but cannot prove the drugs directly cause the hair loss, and the authors themselves called for more research into the underlying mechanism ^[2].

What happens next

The study appeared as a research letter in JAAD International, with an online posting dated February 9, 2026, after first being presented at the EADV congress ^[2]. The authors said future work should look more closely at the biological mechanisms behind the hair loss, track patients prospectively rather than through past records, and gather enough pediatric data to know whether children and teens on these drugs face similar risks ^[2].