# Long-Term Efficacy and Safety of755-nm Alexandrite Laser for Axillary Hair Removal: ِA Comparative Analysis of Single vs. DualFlash lamp Systems

## TL;DR

This study compares the long-term effectiveness and safety of two laser systems for underarm hair removal, finding both are similarly effective with no major side effects.

## Contribution

The study provides a comparative analysis of single- and dual-flash lamp alexandrite lasers for axillary hair removal over a long-term follow-up period.

## Key findings

- Both single- and dual-flash lamp lasers achieved over 90% hair reduction in the axilla.
- No statistically significant difference in efficacy was found between the two systems.
- No serious adverse effects were reported with either laser system.

## Abstract

Laser hair removal is a noninvasive cosmetic procedure that targets melanin in hair follicles through selective photothermolysis.

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.

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.

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.

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.