Long-Term Efficacy and Safety of Low-Level Laser Therapy for Androgenetic Alopecia: A 12-Month Prospective Trial

Abstract

Background: Low-level laser therapy (LLLT) has emerged as a nonpharmacologic intervention for androgenetic alopecia (AGA), but evidence on its long-term efficacy remains limited. Objective: To evaluate the 12-month effectiveness and safety of a home-use helmet-type LLLT device in individuals with AGA. Materials and Methods: This prospective, open-label study enrolled 68 patients (51 men, 17 women) with mild to severe AGA. Participants used a helmet-type LLLT device emitting red light (646–675 nm) three times per week for 20 min over 48 weeks. Hair density and shaft thickness were assessed using phototrichogram at predefined intervals. Additional evaluations included blinded global photographic assessments and patient-reported outcomes. Results: Hair density increased significantly from a baseline mean of 99.2 ± 27.7 to 124.2 ± 33.1 hairs/cm2 at 48 weeks (mean change +25.0 ± 28.1, p < 0.0001). Mean hair shaft thickness rose from 65.1 ± 11.8 to 74.9 ± 12.6 μm (p < 0.0001), reflecting an approximate 15% improvement. Gains were consistent across sexes and AGA severity levels. By Week 48, 59% of participants were rated as improved based on global photographs, and over 85% expressed satisfaction with treatment. No adverse events related to the device were reported, and adherence was high throughout the study. Conclusion: Twelve months of home-use LLLT resulted in sustained improvements in hair density and thickness with excellent tolerability. These findings support its role as a safe, effective, and user-friendly long-term therapeutic option for patients with AGA.