Quantitative assessment of growing hair counts, thickness and colour during and after treatments with a low-fluence, home-device laser: a randomized controlled trial.

BACKGROUND: At-home laser and intense pulsed-light hair removal continues to grow in popularity and availability. A relatively limited body of evidence is available on the course of hair growth during and after low-fluence laser usage. OBJECTIVES: To assess growing hair counts, thickness and colour quantitatively during and after cessation of low-fluence laser treatment. METHODS: Thirty-six women with skin phototypes I-IV and light to dark-brown axillary hairs were included. Entire axillary regions were randomized to zero or eight self-administered weekly treatments with an 810-nm home-use laser at 5·0-6·4 J cm(-2). Standardized clinical photographs were taken before each treatment and up to 3 months after the final treatment for computer-aided quantification of growing hair counts, thickness and colour. RESULTS: Thirty-two women completed the study protocol. During sustained treatment, there was a reduction in growing hair that reached a plateau of up to 59%, while remaining hairs became up to 38% thinner and 5% lighter (P < 0·001). The majority of subjects (77%) reported 'moderately' to 'much less hair' in treated than untreated axilla, and assessed remaining hairs as thinner and lighter (≥ 60%). After treatment cessation, hair growth gradually returned to baseline levels, and 3 months after the final treatment the count and thickness of actively growing hair exceeded pretreatment values by 29% and 7%, respectively (P ≤ 0·04). CONCLUSIONS: Sustained usage of low-fluence laser induced a stable reduction of growing hair counts, thickness and colour. The reduction was reversible and hairs regrew beyond baseline values after cessation of usage. Computer-aided image analysis was qualified for quantification of hair counts, thickness and colour after laser epilation.

Laser and intense pulsed light hair removal technologies: from professional to home use.

Light-based hair removal (LHR) is one of the fastest growing, nonsurgical aesthetic cosmetic procedures in the United States and Europe. A variety of light sources including lasers, e.g. alexandrite laser (755 nm), pulsed diode lasers (800, 810 nm), Nd:YAG laser (1064 nm) and broad-spectrum intense pulsed light (IPL, 590-1200 nm), are available and used widely for such procedures in dermatological/clinical settings under proper supervision. Patient selection and appropriate fluence settings are managed by professionals to maximize efficacy while minimizing adverse events. In the past 5 years, LHR devices have been sold directly to consumers for treatment in the home. In this review, we outline the principles underlying laser and IPL technologies and undertake an evidence-based assessment of the short- and long-term efficacy of the different devices available to the practising dermatologist and discuss the efficacy and human safety implications of home-use devices.