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 ® 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 triplewavelength 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.

Study on the efficacy and safety of a high‐power triple wavelength diode laser (810, 940, 1060 nm) for removing fine and less pigmented facial hair on Asian skin

“…This outcome suggests that, through the use of the triple wavelength diode laser, patients with darker skin types could achieve similar results to those achieved in subjects with lighter skin. 20 Indeed, the recent study by Pall et al, resulted in 27% greater hair reduction in Indian patients with a triple wavelength (810, 940, and 1060 nm) laser compared with a standard 810 nm diode laser. 20 Other reports in the literature demonstrated that the high-power 4000 W Primelase triple wavelength diode laser was shown to be effective and satisfactory on darker skin types, while also being safe and comfortable for participants.…”

“…20 Indeed, the recent study by Pall et al, resulted in 27% greater hair reduction in Indian patients with a triple wavelength (810, 940, and 1060 nm) laser compared with a standard 810 nm diode laser. 20 Other reports in the literature demonstrated that the high-power 4000 W Primelase triple wavelength diode laser was shown to be effective and satisfactory on darker skin types, while also being safe and comfortable for participants. 5,17,18,20 Fajardo-Urdiales et al…”

“…5,21 In accordance with this report, in silico comparison between a triple wavelength diode laser and a standard 810 nm diode laser revealed that higher fluences could be used with the triple wavelength laser to achieve the same epidermal temperature of 43°C obtained with the 810 nm laser. 20 Indeed, numerical simulations serve as a valuable complement to clinical settings, offering insights challenging to obtain through traditional experimental conditions. In the present study, the in-silico simulations allow us to determine crucial factors, such as skin temperature and hair thermal damage, particularly significant for individuals with high skin phototypes and dark, thin hairs.…”

“…Another highly notable outcome of the simulation is that it enabled the determination of the highest possible operating settings for each skin type and wavelength. 20 The use of shorter wavelengths on darker skin brings about complications related to protecting the epidermis since there is increased absorption by the melanin in the skin. The use of higher fluences is possible with longer wavelengths as they are not so readily absorbed by melanin.…”

“…Similar results for both pieces of equipment were produced by the thermal simulations of untreated hair; however, significant differences emerged in the simulations of thinned hair, with the Primelase device boasting an average improvement of 65%. 20 The key factor that enables such an advantage over the Soprano XL is the superior power of the Primelase equipment, which allows shorter laser pulses to be administered, in addition to the option of employing a triple wavelength diode laser with higher fluences in a manner that is safe for skin with a higher concentration of melanin. 5,20 In the study by Gold and colleagues, 18 a comparison between a standard 810 nm diode laser and a triple wavelength diode laser was conducted.…”