Light‐based home‐use devices for hair removal: Why do they work and how effective they are?

Abstract

Objectives This review has the following objectives: Firstly, it provides an explanation of the evolution of laser/intense pulsed light (IPL) hair reduction modalities from high fluence professional devices to low fluence home‐use appliances. Secondly, it summarises published literature reviews on home‐use devices (HUDs) as evidence of their growing credibility. Thirdly, it proposes mechanistic differences in light delivery regimes and the resulting divergences in mode of action. Materials and Methods An extensive literature search was performed to review the progress of laser/IPL‐induced hair reduction and determine what evidence is available to explain the mode of action of professional and HUDs for hair removal. Establishing the likely biological mode of action of professional high‐fluence systems versus home‐use low‐fluence appliances was performed by combining data obtained using ex vivo hair follicle (HF) organ culture and the clinical results involving human participants. Results Significant basic science and clinical evidence has been published to confirm the clinical efficacy and technical safety of many laser and IPL home‐use devices for hair removal. Clearly, HUDs are different compared to professional systems both in terms of fluence per pulse and in terms of biological mechanisms underlying hair removal. Here we presented data showing that a single low fluence pulse of both 810 nm laser (6.6 J/cm2, 16 ms) and IPL (9 J/cm2, 15 ms and 6.8 J/cm2, 1.9 ms) leads to induction of catagen transition. Catagen transition was characterized by morphological changes similar to what occurs in vivo with occasional detection of apoptosis in the dermal papilla and outer root sheath cells. This suggests that high hair reduction can be expected in vivo and longer‐term treatment might result in HF miniaturization due to a cumulative effect on the dermal papilla and outer root sheath cells. In line with this hypothesis, in this review we demonstrate that long‐term application of a commercially‐available home‐use IPL appliance resulted in persistent hair reduction (80%) one year after last treatment. These data are in line with what was previously reported in the literature, where clinical studies with home‐use IPL appliances demonstrated high efficacy of hair reduction on female legs, armpits and bikini zones, with full hair regrowth after four treatments following cessation of IPL administration. Limitations of HUDs include lack of hair clearance for very dark skin types and low speed of treatment compared with professional devices. Numerous uncontrolled and controlled clinical efficacy studies and technical safety investigations on consumer‐use appliances support many of the leading manufacturers' claims. Analysis & Conclusions Manufacturers make consumer appliances safe and easy to use by considering “human factors,” needs and capabilities of a variety of users. Safety is of primary concern to manufacturers, regulators and standards bodies as these appliances may be accessible to children or their use attempted on uns...

Polycystic Ovary Syndrome: Pathophysiology, Presentation, and Treatment With Emphasis on Adolescent Girls

“…Light-based home-use devices are also available and approved by the US Food and Drug Administration. These devices provide less optical energy and should be carefully used to avoid injuries to skin and eyes [200, 201]. Fewer RCTs have evaluated the efficacy of these devices [202].…”

Light-Based Home-Use Hair Removal Devices

“…However, in general, the fluence is lower compared to professional lasers. [ 9 ] Although this reduces efficacy, the positive aspect is that this ensures a better safety profile. This is reflected in our study too, where the safety profile seemed to be very good, but the self-perceived efficacy, as compared to professional lasers, was less.…”

“…It is also suggested that it might be a good “companion” or adjunct treatment to maintain the results from professional hair removal lasers. [ 9 ]…”

Dose‐response of human follicles during laser‐based hair removal: Ex vivo photoepilation model with classification system embracing morphological and histological features

“…Photoepilation is a common method to remove unwanted body hair using pulses of laser or intense pulsed light (IPL), implemented both in professional systems and in home‐use devices (HUDs) . During photoepilation light is selectively absorbed by the melanin in the growing hair follicle (HF), resulting in a local temperature increase .…”