Abstract
BACKGROUND: Laser hair removal is a noninvasive cosmetic procedure that targets melanin in hair follicles through selective photothermolysis. OBJECTIVE: This study aims to evaluate the long-term efficacy and safety of the 755-nm alexandrite laser for axillary hair removal by comparing single- and dual-flash lamp systems. METHODS: In total, 40 women aged 20 to 35 years with Fitzpatrick skin types II and III participated in a study on laser hair removal for their axillae. Participants underwent 3 treatment sessions, each spaced 4 weeks apart, from January to April 2024. They were divided into 2 groups, both receiving treatments with an alexandrite laser (755 nm, 14 mm spot size). The first group was treated with a dose of 8 J/cm² using a single-flash lamp device operating at 5 Hz, with a pulse duration of 10 ms. The second group received doses between 9 and 11 J/cm² from a dual-flash lamp device operating at 2.5 Hz, with pulse durations ranging from 10 to 15 ms. Photographs and hair counts were taken at baseline and 1 month after the final session. A 2-tailed t test was used to assess statistical significance, and regression analysis evaluated treatment effects. Pain scores and side effects were assessed using a visual analog scale in a satisfaction questionnaire. RESULTS: The dual-flash lamp laser achieved an overall hair reduction of 94%, while the single-flash lamp laser resulted in a 91% reduction in the axilla. The difference was not statistically significant (P=.14). No serious adverse effects were reported with either device, indicating effective safety features. CONCLUSIONS: The outcomes show that both systems provide similar results in terms of efficacy and safety, with no reported side effects, and results were maintained even after 6 and 12 months of follow-up.