Photobiomodulation Therapy With Different Wavebands for Hair Loss: A Systematic Review and Meta-Analysis

BACKGROUND Photobiomodulation is a promising therapy for hair loss with negligible side effects. However, the reported effects of photobiomodulation therapy for hair loss are inconsistent. OBJECTIVE To assess the curative effect of photobiomodulation therapy for the treatment of hair loss. METHODS A systematic review of self-controlled studies and randomized controlled trials was conducted. ScienceDirect, PubMed, and Wiley Online Library were searched from the earliest date to May 30, 2021. RESULTS Thirty-six studies (966 patients) were included. Two to 4 meta-analyses with different indices were performed separately on 4 groups of studies to test the effectiveness of the following hair loss treatments: ultraviolet light for alopecia areata (AA), red light for androgenetic alopecia (AGA), infrared light for AA, and infrared light for AGA. All meta-analyses showed that treatments were superior to control ( p < .05). CONCLUSION The meta-analyses strongly suggested that photobiomodulation therapies with ultraviolet and infrared light were effective for treating AA, and photobiomodulation therapies with red light and infrared light were effective for treating AGA.