Hair removal using topical suspension-assisted Q-switched Nd:YAG and long-pulsed alexandrite lasers: A comparative study

Randomized, side-by-side comparison of a topical photo-enhancer gel for hair removal: an efficacy and safety study

Background: Novel protocols are evolving to enhance hair follicle damage while preserving safety and improving efficacy. Objectives: The safety and tolerability of a 755-nm diode laser was compared to a combined laser with topical photo-enhancer gel ("combined") versus laser alone ("solo"). Methods: Twenty women (age 23-33 years old), Fitzpatrick skin type I-V, were randomized to side-by-side comparisons with a laser hair removal protocol. The combined side received reduced laser energy compared to the solo side. The laser used in-motion super hair removal technology. Subjects received up to four treatments. Subjects were assessed at baseline and at 1 and 6 months after the last treatment. Results: At the 1-month follow-up, there were no statistical differences in percent hair reduction between the combined (81 ± 16%) versus the solo (77 ± 15%) protocols (p > 0.05). Similarly, at 6-month follow-up, there are no statistical differences between the combined (71 ± 24%) versus the solo (70 ± 23%) treatment protocols (p > 0.05). The average accumulative laser energy in the combined side was half of the solo side (4.2 ± 1.6 vs. 7.6 ± 2.7 kJ, respectively). Pain during the procedure was significantly higher in the solo (5.5 ± 1.8) versus the combined (3.8 ± 1.7) protocol (p < 0.001). Conclusion: A laser hair removal paradigm that combines a 755-nm diode laser with a photo-enhancer gel (reduced kJ protocol) is clinically effective as a solo treatment protocol.

Laser- and light-based hair removal: an update

A variety of laser technologies are now able to successfully remove unwanted hair. Successful removal is based on an understanding of laser physics and appropriate wavelengths, pulse durations and cooling of the skin. Although ruby lasers were among the first to be used, alexandrite, diode and neodymium-doped yttrium aluminium garnet (Nd:YAG) lasers, as well as a variety of broad-spectrum intense pulsed light sources, are currently more commonly used for the treatment of unwanted hair. Darker skin types are more difficult to treat but can also be treated. Complications can occur after laser hair removal but can be reduced through an understanding of the fundamentals of laser removal. These complications include the obvious, such as scarring and pigmentary changes, and the not so obvious, such as reticulate erythema and uveitis. Laser hair removal is now widely accepted as a successful approach to remove unwanted hair in both men and women. The future will involve office-based laser and light source hair removal, as well as a variety of laser and light-based home devices.

Laser and photoepilation for unwanted hair growth

BACKGROUND

Unwanted hair growth is a therapeutic challenge and considerable resources are spent to achieve a hair-free appearance. Epilation with laser devices (alexandrite, diode, neodymium:YAG, and ruby lasers) and intense pulsed light are commonly used although the long-term effect is uncertain.

OBJECTIVES

To assess the effects of epilation with lasers and light sources.

SEARCH STRATEGY

We searched the Cochrane Skin Group's Specialised Register in February 2004; MEDLINE (from 1966) and EMBASE (from 1980) in April 2005. We searched reference lists of collected trials and contacted trial authors.

SELECTION CRITERIA

Randomised controlled trials of laser or photoepilation.

DATA COLLECTION AND ANALYSIS

Primary outcomes were objective reduction in hair counts, adverse effects and subjective reduction in hairiness. Secondary outcomes were participants satisfaction and personal observations such as softer, finer, or paler hairs. Two authors independently extracted data and assessed trial quality.

MAIN RESULTS

We included eleven randomised controlled trials involving 444 people, none of which were of high methodological quality. A large number of trials were excluded, mainly because of their non-randomised design. The randomisation procedures were either unclear or inadequate, using coin tossing, alternation, drawing lots or cards, or open tables of random numbers. The interventions and outcomes were too heterogeneous to be entered in a meta-analysis. Most trials examined a short-term effect up to six months after final treatment. There appeared to be a short-term effect of approximately 50% hair reduction with alexandrite and diode lasers up to six months after treatment, whereas little evidence was obtained for an effect of intense pulsed light, neodymium:YAG or ruby lasers. Long-term hair removal was not documented with any treatment. Pain, skin redness, swelling, burned hairs and pigmentary changes were infrequently reported adverse effects.

AUTHORS' CONCLUSIONS

Some treatments lead to temporary short-term hair removal. High quality research is needed on the effect of laser and photoepilation.

Evidence-based review of hair removal using lasers and light sources

BACKGROUND

Unwanted hair growth remains a therapeutic challenge and there is a considerable need for an effective and safe treatment modality.

OBJECTIVE

From an evidence-based view to summarize efficacy and adverse effects from hair removal with ruby, alexandrite, diode, and Nd:YAG lasers and intense pulsed light (IPL).

METHODS

Original publications of controlled clinical trials were identified in Medline and the Cochrane Library.

RESULTS

A total of 9 randomized controlled (RCTs) and 21 controlled trials (CTs) were identified. The best available evidence was found for the alexandrite (three RCTs, eight CTs) and diode (three RCTs, four CTs) lasers, followed by the ruby (two RCTs, six CTs) and Nd:YAG (two RCTs, four CTs) lasers, whereas limited evidence was available for IPL sources (one RCT, one CT). Based on the present best available evidence we conclude that (i) epilation with lasers and light sources induces a partial short-term hair reduction up to 6 months postoperatively, (ii) efficacy is improved when repeated treatments are given, (iii) efficacy is superior to conventional treatments (shaving, wax epilation, electrolysis), (iv) evidence exists for a partial long-term hair removal efficacy beyond 6 months postoperatively after repetitive treatments with alexandrite and diode lasers and probably after treatment with ruby and Nd:YAG lasers, whereas evidence is lacking for long-term hair removal after IPL treatment, (v) today there is no evidence for a complete and persistent hair removal efficacy, (vi) the occurrence of postoperative side-effects is reported low for all the laser systems.

CONCLUSION

The evidence from controlled clinical trials favours the use of lasers and light sources for removal of unwanted hair. We recommend that patients are pre-operatively informed of the expected treatment outcome.

The use of a new diode laser for hair removal

BACKGROUND

Diode and long-pulse 1064 Nd:YAG lasers, because of their long wavelengths and extended pulse durations, have gained popularity over the last several years for photoepilation in individuals with dark skin phenotypes.

OBJECTIVE

To analyze the clinical efficacy and histologic features of a new 810-nm diode laser in the treatment of unwanted hair in individuals with Fitzpatrick skin types II-IV.

METHODS

Twenty-four female subjects (mean age, 33; range, 17-53) were treated three times at monthly intervals with the MeDioStarâ diode laser (Zeiss-Meditech, Jenna, Germany): wavelength 810 nm, spot size 12 mm, pulse duration 50 msec; fluence 25-35 J. Patients had skin types II-IV and light to dark brown hair. Hair counts were carried out using handheld magnifiers at baseline and at months 1, 2, 3, and 6. Six individuals had biopsies taken after treatment and at 3 and 6 months.

RESULTS

A mean hair removal efficiency of 74% and 79% was noted at 3 and 6 months, respectively, and was best in those individuals with skin type III. Hair counts after treatment and at last follow-up were significantly lower when compared with the baseline counts (P<0.0001). Histologic analysis revealed a range from early catagen induction to complete follicular destruction.

CONCLUSIONS

This study supports the clinical photoepilatory efficiency of a new 810-nm diode laser in producing 70% clinical hair removal efficiency at 6 months. Histopathologic evaluation suggests that this decrease in hair counts is probably secondary to heat trauma to the follicular epithelium, resulting in complete follicular destruction and stopping of anagen phase.

Evaluation of a new super-long-pulsed 810 nm diode laser for the removal of unwanted hair: the concept of thermal damage time

BACKGROUND

Laser hair removal is based on the dual concepts of selective photothermolysis and thermal relaxation time. In most laser hair removal systems, light with emitted pulse durations of 2-50 msec targets hair follicles. A novel concept of laser hair removal uses the thermal damage time rather than the thermal relaxation time of the hair follicle. The follicle's thermal damage time is the amount of time required for diffusion of delivered laser energy from the treated hair to follicular-associated hair stem cells. This can range from 170 to 1000 msec.

OBJECTIVE

To investigate the theory of thermal damage time, we performed a pilot study to evaluate the clinical efficacy and side effect profile of a modified 810 nm diode laser device operating in a super-long-pulse mode (200-1000 msec).

METHODS

Ten female subjects with Fitzpatrick skin types I-VI received either one or two laser treatments at eight test sites. Super-long pulse durations of 200-1000 msec were evaluated with delivered fluences ranging from 23 to 115 J/cm2. Subjects were followed for 6 months after the first treatment. Subjects were evaluated for hair removal efficiency, optimal pulse duration and delivered fluence, and associated complication rate.

RESULTS

The clinical results show that safe hair removal in all skin types can be accomplished with an 810 nm diode laser delivering super-long pulse durations. Pain and complications were greatest at the highest pulse duration (1000 msec) and the highest fluence (115 J/cm2). Optimal hair reduction at 6 months (31%) was achieved at a thermal diffusion time of 400 msec (46 J/cm2).

CONCLUSION

The super-long pulsed 810 nm diode laser can safely remove unwanted hair in a full variety of skin types. Pain and increased risk of complications may preclude the use of the laser at very high fluences and pulse duration in the range of 1000 msec.

Evaluation of a super long pulsed 810-nm diode hair removal laser in suntanned individuals

BACKGROUND

Laser hair removal is based on the dual concepts of selective photothermolysis and thermal relaxation time. In most laser hair removal systems, light with emitted pulse durations of 2-50 ms targets hair follicles. Such pulse durations usually lead to post-inflammatory pigmentary changes in suntanned individuals.

OBJECTIVE

In this pilot study, we evaluated the clinical efficacy and side effect profile of a modified 810-nm diode laser device (Palomar SLP 1000, Burlington, MA, USA) operating in a super long pulse mode (200-1000 ms).

METHODS

Five suntanned subjects with Fitzpatrick skin types II-IV received either one or two laser treatments at eight test sites. Treatments were delivered to suntanned skin. Pulse durations of 200-1000 ms were evaluated with delivered fluences ranging from 23 to 115 J/cm(2). Subjects were followed for 6 months after the first treatment. Subjects were evaluated for hair removal efficiency, optimal pulse duration and delivered fluence, one versus two treatments, and associated complication rate.

RESULTS

The average hair reduction, 34%, did not significantly vary with pulse duration or fluence. Clinical evaluations rated two treatments superior to one.

CONCLUSION

The results show that efficacious and safe hair removal can be accomplished with an 810-nm diode laser delivering super long pulse durations at a wide range of settings in suntanned individuals. For optimal safety in tanned patients, the highest fluence (115 J/cm(2)) and pulse duration (1000 ms) should be avoided.