Hair loss in the era of CGRP inhibition: emerging evidence, mechanisms, and clinical implications.

Introduction: Calcitonin gene-related peptide (CGRP)-targeting therapies have transformed migraine management and are generally associated with a favorable safety profile. However, accumulating real-world evidence suggests a potential association with alopecia that was not systematically captured in pre-approval clinical trials. This review aimed to synthesize current evidence on alopecia associated with CGRP-targeting therapies, with a focus on clinical patterns, pharmacovigilance signals and underlying pathophysiological mechanisms. Methods: A structured literature search of PubMed was conducted to identify relevant evidence on CGRP-targeting therapies and hair loss through August, 2026. Eligible studies included clinical trials, observational studies, pharmacovigilance analyses and case reports reporting alopecia outcomes. Reference lists were screened for additional relevant studies. Due to heterogeneity of study designs and predominance of low-level evidence, findings were synthesized narratively without formal quality assessment. Results: Evidence from pharmacovigilance data and case-based observations suggests a reproducible signal of predominantly reversible, non-scarring alopecia occurring within weeks to months after initiation of CGRP-targeting therapies. Reports span multiple monoclonal antibodies and gepants, supporting a potential class effect. However, the available evidence is largely derived from spontaneous reporting systems and case series, limiting causal inference and precluding reliable estimation of incidence. Proposed mechanisms include neuroimmune dysregulation, impairment of hair follicle immune privilege, reduced microvascular perfusion, and disruption of the CGRP-insulin-like growth factor-1 axis. Conclusion: Alopecia has emerged as a potentially clinically relevant safety signal associated with CGRP-targeting therapies. Although the association is biologically plausible, the available evidence does not establish causality, frequency or the typical clinical course of this adverse event. Most cases appear to be mild, non-scarring and reversible. Given the expanding use of these therapies, increased clinical awareness and individualized management are essential. Future prospective studies with standardized dermatological assessment are needed to better define incidence, risk factors and underlying mechanisms.