Fractional photothermolysis laser treatment of male pattern hair loss

Background Various trials have been conducted on the management of male pattern hair loss (MPHL). A variety of laser and light sources have been used for the treatment of MPHL. OBJECTIVE To understand the effects of a 1,550-nm fractional erbium-glass laser on the hair cycle in an alopecia mouse model and to study the clinical effects of the same laser used as treatment for MPHL. MATERIALS AND METHODS Irradiation was applied to the shaved skin of C3H/HeN mice using various energy and density settings and varied irradiation intervals. In a clinical pilot study involving human subjects, 20 participants were treated over five sessions at 2-week intervals. A fractional photothermolysis laser was used at the energy of 5 mJ and a total density of 300 spots/cm². RESULTS In the animal study, the hair stimulation effects were dependent upon the energy level, density, and irradiation interval. The anagen conversion of hair and the increase in Wnt 5a, β-catenin signals were observed. In the human pilot study, incremental improvements in hair density and growth rate were observed. CONCLUSIONS This pilot study showed that a 1,550-nm fractional erbium-glass laser might induce hair growth, but more intensive studies are required to clarify the clinical applications of this treatment. The authors have indicated no significant interest with commercial supporters.