Background: Androgenetic alopecia (AGA) is a genetically determined condition, which leads to progressive hair loss (HL) of the vertex, affects hair follicles, and promotes partial or total HL. It may be related to important psychological and social distress. Objective: The aim of the study was to evaluate the effects of photobiomodulation (PBM) in patients with AGA. Methods: Twenty-five men 20-54 years of age participated in this study. The irradiations were punctual, in contact mode, with 1 cm between each point covering the entire affected area. A red low-level laser (λ = 660 nm) (Recover®, MMOptics, São Carlos, Brazil) was used with 100 mW, 30 sec, and 3 J per point, twice a week on alternate days for 10 weeks. Evaluations were made by photographic records from the same area before any intervention (T1), after 5 weeks (T2), after 10 weeks (T3). Two blinded evaluators using the ImageJ® software assessed the hair density. Results: The hair density evaluation showed a significant increase in hair count between T1 and T2 (p = 0.0004) and between T1 and T3 (p = 0.0285), however between T2 and T3 no statistical difference was found (p > 0.05). Conclusions: PBM provides a stimulus for hair density in 5 weeks. After this period, we observed that after five extra sessions, it does not increase hair density in the treated region. This study showed that the PBM is effective and promoted safe results with a reduced number of sessions for the AGA treatment.
Keywords: androgenetic alopecia; hair loss; photobiomodulation.