Title: Optimizing treatment parameters for hair removal using a topical carbon-based solution and 1064-nm Q-switched neodymium:YAG laser energy.
Authors: Nanni CA, Alster TS
Journal: Arch Dermatol 1997 Dec;133(12):1546-9
PMID: 9420539, UI: 98082109
Affiliated institution: Washington Institute of Dermatologic Laser Surgery, Washington, DC 20037, USA.
OBJECTIVE: To determine the most effective treatment parameters for laser-assisted hair removal using a Q-switched neodymium:yttrium-aluminum-garnet (Nd:YAG) laser.
DESIGN: Prospective study to determine the effectiveness of Q-switched ND:YAG laser-assisted hair removal under varying pretreatment protocols. Hair growth was assessed after laser treatment, and the results were compared with those of wax epilation at 4, 12, and 24 weeks.
SETTING: A private ambulatory laser facility and academic referral center.
INTERVENTION: Laser-assisted hair removal was performed under 4 different pretreatment conditions. Eighteen areas of unwanted body and facial hair from 12 study subjects were divided into 4 quadrants. Wax epilation followed by application of a carbon-based solution and exposure to Q-switched Nd:YAG laser radiation was performed on 1 quadrant. A second quadrant was wax epilated and exposed to Q-switched Nd:YAG laser radiation without prior carbon solution application. A third quadrant was exposed to laser radiation alone, and a final quadrant was wax epilated to serve as the control. Follow-up evaluations at 1, 3, and 6 months consisted of photographic documentation, manual hair counts, and patient hair-density estimates.
MAIN OUTCOME MEASURE: Percentage of hair regrowth as assessed by objective hair counts and patient subjective evaluations.
RESULTS: Mean percentage of hair regrowth at 1 month was 39.9% for the wax-carbon-laser quadrant, 46.7% for the wax-laser quadrant, 66.1% for the laser-alone quadrant, and 77.9% for the wax control quadrant. The percentage of hair regrowth approximately doubled by 3 months but was significantly delayed in all laser-treated quadrants regardless of pretreatment protocol. Full hair regrowth in all anatomic locations was observed by month 6. Patient subjective evaluations of hair density closely approximated hair count data. No adverse effects or long-term complications were observed.
CONCLUSIONS: A single hair-removal treatment with the Q-switched Nd:YAG laser is safe and effective in delaying hair growth for up to 3 months. Although the combination of pretreatment wax epilation and topical carbon solution application was effective, laser irradiation alone, with or without wax epilation, also provided a significant delay in hair growth.