Prospective study of hair reduction by diode laser (800 nm) with long-term follow-up

BACKGROUND. Multiple laser systems are available for the purpose of hair removal. OBJECTIVE. The purpose of this study was to determine the safety and long-term efficacy of the 800 nm, pulsed diode laser at reducing hair count. METHODS. Fifty volunteers, primarily Fitzpatrick skin types II and III, with dark brown or black hair, were treated with a diode laser (800 nm, 10-40 J/cm(2), 5-30 msec, 9 mm 9 mm, 5 degrees C chilled handpiece). Each subject had eight treatment sites at varying fluences and pulse durations, as well as a varying number of treatments and pulses. Hair counts were obtained at each site at baseline, 1, 3, 6, 9, and an average of 20 months after treatment. RESULTS. After one treatment, hair regrowths ranged from 22 to 31% at the 1-month follow-up visit, then remained stable between 65 and 75% from the 3-month to the averaged 20-month follow-up. After two treatments there were relatively longer growth delays, with hair regrowths plateauing beginning at 6 months after treatment and ranging from 47 to 66% for the remainder of the follow-up evaluations. Side effects were limited to pigmentary changes, transient in subjects with skin types ZI and III. CONCLUSIONS. This 800 nm diode laser with a chilled sapphire tip and variable pulse duration is safe and effective for longterm hair reduction in individuals with skin types II and III.