Title: Long-pulsed alexandrite laser-assisted hair removal at 5, 10, and 20 millisecond pulse durations.
Authors: Nanni CA, Alster TS
Journal: Lasers Surg Med 1999;24(5):332-7
PMID: 10406473, UI: 99333131
Affiliated institution: Washington Institute of Dermatologic Laser Surgery, Washington, DC 20037, USA.
BACKGROUND: Several laser systems with varying wavelengths, pulse durations, and energy fluences are currently utilized for hair removal. However, the ideal laser parameters and treatment candidates for photoepilation remain largely unknown. The medical literature lacks a wealth of experimental data to sufficiently document the long-term safety and efficacy of laser-assisted hair removal. This study examines the clinical efficacy and side effect profile of long-pulsed alexandrite laser-assisted hair removal utilizing laser pulse durations of either 5, 10, or 20 milliseconds (ms).
STUDY DESIGN/METHODS: Laser-assisted hair removal was performed on 36 subjects with a long-pulsed alexandrite laser. Areas of unwanted hair growth on the face, back, and legs were divided linearly into four 1 cm2 or 2 cm2 quadrants. Experimental regions included a control quadrant and three additional quadrants, which were treated with the alexandrite laser using an average fluence of 18 J/cm2, with a 10 mm spot size at either a 5, 10, or 20 ms pulse duration. Hair counts and photographs were obtained before treatment, immediately following irradiation, 1 week and 1, 3, and 6 months postoperatively.
RESULTS: All laser-treated quadrants displayed a significant delay in hair regrowth compared to control nontreated quadrants at postoperative week 1 and months 1 and 3. Hair counts were reduced by 66% at 1 month, 27% at 3 months, and 4% at 6 months. No significant differences in clinical efficacy or side effect profiles were observed between treatment quadrants, yet a trend towards less post-treatment erythema and hyperpigmentation was noted with the 20 ms pulse duration.
CONCLUSIONS: Equivalent long-term hair removal for up to 6 months was achieved with the long-pulsed alexandrite laser at 5, 10, and 20 ms pulse durations at an average fluence of 18 J/cm2. Side effects were limited and transient.