To the Editor: Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are incretin-based therapies widely used for type 2 diabetes mellitus (T2DM) and obesity management. While their cardiovascular and metabolic benefits are well established, emerging reports suggest potential dermatologic adverse effects, particularly nonscarring hair loss (NSHL).1 Pharmacovigilance data and small cohort studies suggest a possible link between GLP-1RAs and hair loss, though evidence remains inconsistent and largely limited to post-marketing surveillance.2,3 Given the growing use of GLP-1RAs, further elucidating their dermatologic side effect profile and safety is essential.
This study used the TriNetX US Collaborative Network, a platform of aggregate de-identified electronic health record data from 67 US healthcare organizations, to evaluate the incidence and risk of NSHL in adults (18-89 years) and adolescents (12-17 years) treated with GLP-1RAs compared with matched controls from 2014 to 2024. Patients with ≥2 GLP-1RA prescriptions were included, while controls had ≥2 general medical encounters and no GLP-1RA exposure. Patients with confounding dermatologic, endocrine, nutritional, or systemic conditions were excluded (Supplementary Table I, available via Mendeley at https://data.mendeley.com/datasets/fhxs63v4s2/1). Propensity score matching accounted for age, sex, race, BMI, and T2DM status. NSHL outcomes, including telogen effluvium (TE), androgenetic alopecia (AGA), and alopecia areata (AA), were identified using ICD-10 codes. Follow-up for HL outcomes began 1 day after the index date and continued through 6- and 12-month intervals. Logistic regression estimated adjusted odds ratios (aORs) with 95% confidence intervals.
Among 547,993 matched adult GLP-1RA users and controls, cohorts were well-balanced (Supplementary Table II, available via Mendeley at https://data.mendeley.com/datasets/fhxs63v4s2/1). Between 2014 and 2024, the incidence of NSHL, TE, AGA, and AA increased in both GLP-1RA users and controls. Beginning around 2019, incidence curves for overall NSHL began to diverge, with GLP-1RA users showing consistently higher rates by 2023-2024. For TE and AGA, rates remained similar until 2021 to 2022 before rising more sharply among GLP-1RA users (Fig 1). Ten or fewer pediatric GLP-1RA users experienced each HL outcome of interest, precluding meaningful comparisons. At 6 months, GLP-1RAs were linked to a higher risk of AGA (aOR 1.62) and NSHL (aOR 1.26) (both P < .001) and increased TE risk (P = .18). At 12 months, risks increased for TE (aOR 1.76), AGA (aOR 1.64), and NSHL (aOR 1.40), all P < .001 (Fig 2).
Fig 1.
Annual incidence trends of hair loss among GLP-1RA users and controls, 2014-2024. Line graphs depict the temporal trends in the incidence of overall non-scarring hair loss and subtypes among individuals treated with GLP-1 receptor agonists compared with matched controls. The left y-axis represents condition-specific incidence proportions (telogen effluvium, alopecia areata, and androgenic alopecia) per 1000 persons. The right y-axis represents the overall incidence of non-scarring hair loss per 1000 persons. Solid lines indicate GLP-1 users, while dot-dash lines indicate control cohorts. Data are scaled using a dual y-axis for visibility of both overall and subtype-specific trends.
Fig 2.
Association between GLP-1RA use and hair loss outcomes at 6 and 12 months. Forest plots displaying adjusted odds ratios (aORs) with 95% confidence intervals for the risk of TE, AGA, AA, and overall NSHL among GLP-1RA users compared with matched healthy controls at 6- and 12-month follow-up. Results show significantly increased odds of TE, AGA, and overall NSHL with GLP-1RA exposure, while no significant association was observed for AA.
In this matched cohort study, GLP-1RA use was associated with an increased risk of NSHL, especially TE and AGA, independent of demographic and clinical factors. TE showed a notable rise among GLP-1RA users, while AGA incidence increased in both groups, reflecting its progressive nature, with a slightly higher rise in GLP-1RA users possibly due to drug-related, metabolic, or surveillance effects. Likely mechanisms include rapid weight loss, insulin/insulin-like growth factor 1 signaling, androgen changes, and direct follicular effects.4 These findings align with prior studies linking alopecia to the GLP-1RAs semaglutide and tirzepatide.3,5 AA was consistently higher in controls, suggesting GLP-1RAs do not significantly affect autoimmune hair loss. In the pediatric subset, a small sample size limited analysis, highlighting barriers to access of GLP-1RAs in children.
Awareness of alopecia risk in patients on GLP-1RAs is critical for early detection, anticipatory guidance, and multidisciplinary care. Future research should examine underlying mechanisms, prospective monitoring, and pediatric outcomes to guide safe and informed GLP-1RA use.
Conflicts of interest
None disclosed.
Footnotes
Authors Vidal and Akiska Co-first authors with equal contributions.
Funding sources: None.
Patient consent: Not applicable.
IRB approval: Not applicable.
References
- 1.Haykal D. Alopecia and semaglutide: connecting the dots for patient safety. J Cosmet Dermatol. 2025;24(3) doi: 10.1111/jocd.70125. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Burke O., Sa B., Cespedes D.A., Sechi A., Tosti A. Glucagon-like peptide-1 receptor agonist medications and hair loss: a retrospective cohort study. J Am Acad Dermatol. 2025;92(5):1141–1143. doi: 10.1016/j.jaad.2025.01.046. [DOI] [PubMed] [Google Scholar]
- 3.Godfrey H., Leibovit-Reiben Z., Jedlowski P., Thiede R. Alopecia associated with the use of semaglutide and tirzepatide: a disproportionality analysis using the FDA adverse event reporting system (FAERS) from 2022 to 2023. J Eur Acad Dermatol Venereol. 2025;39(2):e153–e154. doi: 10.1111/jdv.20197. [DOI] [PubMed] [Google Scholar]
- 4.Kim T.H., Lee K., Park S., et al. Adverse drug reaction patterns of GLP-1 receptor agonists approved for obesity treatment: disproportionality analysis from global pharmacovigilance database. Diabetes Obes Metab. 2025;27(6):3490–3502. doi: 10.1111/dom.16376. [DOI] [PubMed] [Google Scholar]
- 5.Desai D.D., Sikora M., Nohria A., et al. GLP-1 agonists and hair loss: a call for further investigation. Int J Dermatol. 2024;63(9):1128–1130. doi: 10.1111/ijd.17246. [DOI] [PubMed] [Google Scholar]