Novel laser hair removal in all skin types

Laser has been long accepted as a solution for excess or unwanted hair growth yet traditional lasers are not always ideal for safe and effective outcome for all skin types and hair characteristics. A diode laser module combining three wavelengths (755, 810, and 1064 nm) in a single pulse was developed to provide a fast and long‐term solution for subjects with various profiles.


| INTRODUC TI ON
Unwanted hair is a prevalent condition that affects, in various degrees, up to 40% of the female worldwide. 1 Undesired, sometimes excessive, hair growth may be normal, the side effect of medications, or a sign of an underlying pathological condition. 2 Despite being biologically normal in the majority of cases, the presence of unwanted and excessive hair can be distressing to the affected individuals.
Several studies have demonstrated that women with excessive body or facial hair were found to be at a higher risk of body dysmorphic disorder, which is characterized by a constant perception of ugliness and shame. 1 Effective removal of unwanted hair may thus be critical to alleviating its adverse psychological impact. 3 The current management lines for unwanted hair include medical management of any underlying clinical disorder, lifestyle modifications, and/or cosmetic treatments; the latter ranges from mechanical or chemical hair removal (such as creams, bleaching, shaving, or waxing) to the destruction of hair follicles through electrolysis or light-based therapies. 4 Light-based hair removal has emerged as one of the most effective strategies for many dermatological conditions. 5 Lasers are the most widely used phototherapy for hair removal. They act through thermal destruction of the targeted hair follicles, with minimal damage to the surrounding tissues (selective photothermolysis) 6 and are currently the most effective method of long-term hair removal.
Laser systems developed over the past two decades encompass various wavelengths for hair removal include long pulse ruby at 694 nm, long pulse alexandrite (755 nm), long pulse diode (810 nm), and long pulse Nd:YAG (1064 nm). Generally, the current body of evidence shows that lasers exhibit excellent efficacy and safety profiles for unwanted hair removal in normal population. 7 Nevertheless, the challenges of effective hair removal treatments, such as skin melanin content that acts as a competing chromophore for light absorption, affect both hair reduction efficacy and increase the risk of adverse events such as blistering and hyperpigmentation. This is most relevant in individuals with darker skin (phototypes III-VI). It has been shown that subjects with pigmented skin are more prone to laser-related adverse events such as pain, blistering, and dyspigmentation. 7 To minimize the rate of adverse events in these individuals, prolonged pulse-width laser devices and longer treatment duration were proposed. 8 Factors such as skin type and hair color, as well as different levels of hair thickness and depth, affect the appropriate laser selection. [9][10][11] Recently, devices presenting a combination of wavelengths have shown to produce high effective hair reduction with no related risks. 12 Novel diode laser systems combining three wavelengths (755, 810, 1064 nm) in a single pulse have been developed to target different structures of the hair follicle for the removal of unwanted hair and to provide long-term hair reduction suitable for diverse hair varieties and all skin types. This study was designed to clinically evaluate the safety and efficacy of this novel combinational diode laser in patients of the entire range of skin types I-VI.

| Device
The laser device used was the Soprano Titanium (Alma Lasers LTD, Israel) with its large TRIO diode module (4 cm 2 spot size) that bare clustered technology that emits a combination of three wavelengths at 755, 810, and 1064 nm in every single pulse. Laser energy is delivered by a series of high repetitive low fluence pulses (Super Hair Removal-SHR mode), to increase the temperature of both the hair follicle and the surrounding tissue, by carrying the In-Motion™ technique. The constant motion technique gradually heats the surrounding tissue, allowing it to act as a reservoir of heat around the hair follicle. This process, along with the thermal energy absorbed directly by the hair follicle, damages the follicle and prevents re-growth.
Energy is delivered via pulses emitted from a 2 cm 2 or 4 cm 2 spot size, to cover small and large areas, respectively, with pulse width ranging from 3-220 ms and fluence and frequency of up to 10 J/cm 2 and 10 Hz. The modules have an integrated metallic rim sapphire window using thermoelectric contact cooling system (4°C/39°F) to reduce patient discomfort and post procedure side effects.

| Study methodology
This was a dual-site, prospective single-arm study, conducted be-  (Figures 1 and 2), and average percentage of hair reduction by site was calculated. Safety was evaluated by monitoring of any adverse events during and post treatments. In addition, tolerance to the treatment was assessed both by the investigators and the subjects before and after each treatment session. The investigators used the 5-point Likert scale in the following 4 categories: erythema, edema, dryness, and peeling, while the subjects used the same scale with different categories: stinging, tingling, itching, and burning.

| Statistical analysis
All tests were 2-tailed, and a p-value of 5% or less was considered statistically significant. The data were analyzed using SAS® software, version 9.4 or higher (SAS Institute, Cary, North Carolina). Remarkable results of hair count reduction were observed in both treated areas (axilla and bikini line). Table 1

| DISCUSS ION
The ability to adjust and integrate wavelengths arises as a promising solution for the safe and effective removal of unwanted hair that will benefit all skin types. This study presents the results of TA B L E 1 Relative change (%) from baseline to 3 M FU in hair count in all subjects.

Skin type I-IV
Skin type V-VI All skin types would have been more effective in determining the treatment's long-term effects. Therefore, additional studies on hair removal with laser devices combining three wavelengths in a single pulse, and at least 6 months follow-up period are required to support the insights achieved in this study.

AUTH O R CO NTR I B UTI O N S
The authors contributed to the design and implementation of the research, to the analysis of the results, and to the writing of the manuscript.

ACK N OWLED G M ENTS
Editorial assistance was performed by Angela Brown.

D I SCLOS U R E S
Dr. Gold performs clinical research for Alma Lasers.

DATA AVA I L A B I L I T Y S TAT E M E N T
The authors confirm that the date supporting the finding of this study are available within the article

E TH I C A L A PPROVA L
The paper reflects the authors' own research and analysis in a truthful and complete manner.