Efficacy and safety of hair removal with a long-pulsed diode laser depending on the spot size: A randomized, evaluators-blinded, left-right study

Seong Jin Jo, Jin Yong Kim, Juhee Ban, Youngjoo Lee, Ohsang Kwon, Wooseok Koh

Research output: Contribution to journalArticle

8 Scopus citations


Background: The efficacy of the long-pulsed diode laser (LPDL) in hair removal is determined with various physical parameters. Recently, LPDLs with a larger spot size are commercially available; however, the independent effect of spot size on hair removal has not been studied. Objective:This study aimed to compare the efficacy of the LPDL in hair removal depending on the spot size. Methods: A randomized, evaluators-blind, intrapatient comparison (left vs. right) trial was designed. Ten healthy Korean women received three hair removal treatment sessions on both armpits with the 805-nm LPDL and followed for 3 months. A 10×10 mm handpiece (D1) or a 10×30 mm handpiece (D3) was randomly assigned to the right or left axilla. The fluence, pulse duration, and epidermal cooling temperature were identical for both armpits. Hair clearance was quantified with highresolution photos taken at each visit. Postprocedural pain was quantified on a visual analogue scale. Adverse events were evaluated by physical examination and the patients' self-report. Results: The mean hair clearance at 3 months after three treatment sessions was 38.7% and 50.1% on the armpits treated with D1 and D3, respectively (p=0.028). Procedural pain was significantly greater in the side treated with D3 (p=0.009). Serious adverse events were not observed. Conclusion: Given that the pulse duration, fluence, and epidermal cooling were identical, the 805-nm LPDL at the three times larger spot size showed an efficacy improvement of 29.5% in axillary hair removal without serious adverse events.

Original languageEnglish
Pages (from-to)517-522
Number of pages6
JournalAnnals of Dermatology
Issue number5
StatePublished - 1 Oct 2015


  • Hair
  • Hair removal
  • Laser spot size
  • Long pulsed diode laser

Cite this