Improved Laser Hair Removal Efficacy Using 2 ms Versus 3 ms Pulse Widths
Konika Patel Schallen, MD
Source publication: Improved Laser Hair Removal (LHR) Efficacy Using 2 ms vs 3 ms Pulse Widths
Introduction
Laser hair removal is based on selective photothermolysis, in which light is absorbed by melanin in the hair follicle while surrounding skin is protected. Wavelength, fluence, spot size, pulse duration, and cooling all influence the result. This clinical bulletin examined one specific variable: whether a shorter 2 millisecond pulse could improve reduction of fine, resistant hair compared with a 3 millisecond pulse.
What the publication studied
Fourteen subjects completed a split-side study using the GentleMax Pro Plus platform. One side of each treatment area received a 2 ms pulse and the opposite side received a 3 ms pulse, while spot size and fluence were kept consistent. Ten subjects were treated with the 755 nm alexandrite wavelength and four with the 1064 nm Nd:YAG wavelength. Treatment areas included the axilla, back, legs, face, and flanks. Four sessions were performed at eight- to twelve-week intervals, followed by three- and six-month evaluations.
Key findings
At six months, four reviewers evaluated paired photographs. Reviewers correctly identified the 2 ms-treated side in 88.6% of the image pairs. The average improvement score was 58.5% for the 2 ms side and 48.5% for the 3 ms side. At 755 nm, average improvement was 57.3% with 2 ms versus 46.1% with 3 ms. At 1064 nm, average improvement was 65.4% with 2 ms versus 57.1% with 3 ms. The differences were statistically significant. Mild perifollicular edema and erythema were expected after treatment, and no adverse events were recorded.
CMA Medicine review
The study helps explain why laser hair removal should not be approached as a one-setting-fits-all service. Fine residual hairs have a shorter thermal relaxation time than coarse hairs and may respond differently to pulse duration. The findings suggest that a 2 ms setting may be particularly useful later in a treatment series, when remaining hairs are finer and more resistant. Wavelength selection remains equally important: 755 nm is generally favored for lighter skin with dark hair, while 1064 nm is commonly selected for darker skin types.
What this may mean for patients
Patients who have completed several laser hair removal sessions but still have fine, dark, treatment-resistant hair may benefit from a more customized approach rather than simply repeating the same settings. A qualified provider should evaluate hair caliber, skin type, treatment history, and response before adjusting pulse duration or wavelength.
Download the clinical bulletin to review the split-side protocol, treatment parameters, six-month photographic evaluation, and statistical analysis.
