Triple Wavelength and 810 nm Diode Lasers for Hair Removal: A Clinical and <i>in Silico</i> Comparative Study on Indian Skin

Abstract

In laser hair removal treatments on dark skin, the high concentration of melanin in the skin competes with the melanin in the hair. During standard laser procedures, with wavelengths of 755 nm or 810 nm, a high level of laser light absorption by melanin in the skin is observed. Therefore, to avoid side effects, lower fluence values are used, which further reduces hair-removal efficacy. To improve results, 810 nm diode lasers operating in dynamic mode, with high frequency and multiple passes, are typically used. The aim of this study is to compare the efficacy and safety of triple-wavelength diode lasers (810 nm, 940 nm, 1060 nm) with that of 810 nm diode lasers on Indian patients. A side-by-side comparison was performed using a triple-wavelength diode laser in stamping mode on one side, and an 810 nm diode laser in dynamic mode on the other. Three subjects with skin type IV on the Fitzpatrick scale participated in the study. Efficacy was assessed through hair counting using clinical photographs, taken before and after the treatments, and the Global Aesthetic Improvement Scale (GAIS). Additionally, comparisons related to epidermal heating and thermal damage to the hair follicle were conducted through mathematical 3D simulations using COMSOL Multiphysics &#174; software. Side effects were also evaluated. A superior end point was observed with triple wavelength compared to the 810 nm diode laser. Hair counting showed a 27% greater hair reduction with triple wavelength. No adverse effects were observed. Thermal simulations revealed 29% higher thermal damage with the triple-wavelength laser compared to the 810 nm diode laser. To conclude, on darker skin types, the triple-wavelength diode laser has been shown to be more effective at removing hair, compared to the 810 nm diode laser, while also being a safe procedure.