GLP-1 Receptor Agonists and Alopecia: A Systematic Review and Meta-analysis of Incidence, Risk, Subtypes, and Mechanisms

Background: GLP-1 receptor agonists (GLP-1 RAs) are among the fastest-growing pharmacological classes globally. Alopecia has emerged as a clinically relevant adverse effect, yet subtype-specific pooled estimates of risk are lacking. Methods: PubMed/MEDLINE, Embase, Cochrane Central, Web of Science, and Scopus were searched from inception to March 2026 with no language restrictions. Studies reporting alopecia in adult GLP-1 RA users were eligible. Of 1,847 records identified, 17 met eligibility criteria. Random-effects meta-analyses (DerSimonian-Laird) were performed. The protocol was registered in PROSPERO (CRD420261335458). Results: Seventeen studies encompassing 1,091,743 patient-exposures were included. The pooled OR for any non-scarring alopecia was 1.40 (95% CI, 1.33–1.48; I²=0%). Significant associations were found for telogen effluvium (aOR, 1.76; 95% CI, 1.34–2.32) and androgenetic alopecia (aOR, 1.64; 95% CI, 1.35–1.99) at 12 months. Semaglutide (ROR, 2.46) and tirzepatide (ROR, 1.73) showed the highest pharmacovigilance signals. Paradoxically, 58% of patients with central centrifugal cicatricial alopecia showed improvement. Conclusion: GLP-1 RAs are associated with a significant 40% increased risk of non-scarring alopecia, primarily mediated by weight loss-induced micronutrient deficiency. Dermatologists should counsel patients proactively and avoid premature drug discontinuation.