Lasers useful for promoting hair growth
Publish date: Jun 1, 2010
By: Joely Kaufman, M.D., Bernard Nusbaum, M.D.
Source: Dermatology Times
* Most reports on lasers and hair growth originated from hair removal literature
* LLLT with red light stimulates terminal hair growth on hair count analysis, but results difficult to judge
* Several devices on market for at-home hair growth treatment
Joely Kaufman, M.D.
Most of the time, when lasers are discussed in the context of hair, it is regarding the removal of hair. It was not until fairly recently that these devices received significant attention for their role in stimulating hair growth.
Bernard Nusbaum, M.D.
Androgenetic alopecia (AGA) affects more than 35 million men and 21 million women in the United States. Due to the relative lack of viable nonsurgical treatment options for AGA, the therapeutic focus has once again turned to lasers.
The idea of using light to stimulate hair growth was first published in the 1960s and involved mice studies (Mester E, Szende B, et al. Kiserl Orvostud. 1967;19:628-631). Despite this history, the mechanism of action of how lasers may function to prevent, stop or even promote growth in AGA is still unknown.
LLLT and hair growth
There is clear evidence that low-level lasers alter cell function in some manner, and low-level laser therapy (LLLT) for wound healing, pain, anti-aging and inflammation is a popular modality. In vitro studies with different wavelengths have shown modulation of cell activity, including increased mitochondrial activity as well as increased production of ATP.
This "stimulatory effect" of light therapy is what has driven scientists and physicians to explore low-level laser photobiomodulation for hair growth. Clinically, LLLT does seem to provide some effect, although in some treatments it is difficult to measure. When it comes to AGA, most of the focus has been on red and near-infrared light devices (600 nm to 950 nm).
Ironically, many of the reports on hair growth and lasers actually originated from laser hair removal literature. Stimulation of hair growth is an adverse event associated with hair removal with intense pulsed light (IPL), diode and alexandrite lasers. If we could predictably control this "adverse event" and elicit it in patients who actually desire more hair, a new therapeutic option could emerge.
Hair growth studies
Laser-induced hair growth in mice has been replicated using several different devices, including a helium-neon (He-Ne) laser (Shukla S, et al. Skin Pharmacol Physiol. 2010;23(2):79-85). In this study, mice treated with the He-Ne laser had a much higher percentage of hairs in anagen phase than those not treated.
There is one published double-blind, sham device-controlled, multicentered study on hair growth (Leavitt M, et al. Clin Drug Invest. 2009;29(5):283-295). A total of 123 patients with AGA were enrolled. Hair counts were completed, as were photographic assessments and patient self-assessment scores. The treatment group used a low-level laser comb 15 minutes a day, three days a week, for a total of 26 weeks. Hair counts at the end of six months showed a statistically significant (p<.0001) difference in hair density counts between the laser group and the sham group (+19.8 hairs/cm2 vs. -7.6 hairs/cm2 ). There was also a statistically significant difference in the subjects' self assessments.
While LLLT with red light does stimulate terminal growth on hair count analysis, the clinical improvement is more difficult to judge. The study did not evaluate for any textural changes in hair. Textural changes may make hair appear clinically fuller, and patients may be happy with "thicker" hair that doesn't necessarily exhibit a higher hair count. It may be that longer treatment sessions or duration of the treatment is needed. It may also be more helpful clinically when used in combination with other therapies, such as hair transplant, finasteride or minoxidil.
Optimum treatment frequency and duration have not yet been determined for hair-growth laser therapy, and it is theoretically possible that large overdoses could reverse the therapeutic effects. In other words, more power with LLLT does not necessarily translate into better results. Long-term follow-up of patients receiving LLLT for AGA is needed to determine if therapeutic benefits can be maintained with prolonged therapy.
In summary, LLLT is a safe, tolerable and easy-to-use treatment option for patients with AGA. Hair counts have been shown to increase in the only double-blinded study published. Proper parameters and treatment regimens must be better elucidated in order to make this treatment more universally accepted.
At this point, LLLT (red, 630 nm to 670 nm) for AGA seems to show some effects in some patients, yet future studies are needed to optimize results by better defining treatment power, dosing and frequency. With so few reliable noninvasive therapeutic choices for AGA, laser therapy is a welcome addition.
Joely Kaufman, M.D., is assistant professor of clinical dermatology at the University of Miami Miller School of Medicine and director of lasers for the University of Miami Cosmetic Group.
Bernard Nusbaum, M.D., is a board-certified dermatologist specializing in hair loss and hair restoration. He is past president of the American Board of Hair Restoration Surgery and co-editor of Hair Transplant Forum International.
Comments from our Readers
Dr. Alan Bauman / Boca Raton, FL, UNITED STATES
Posted 2010-06-02 07:23:26.0
Drs. Nusbaum and Kaufman, I read with much excitement your article on LLLT and hair growth. Having successfully used Low Level Laser Therapy in my own hair restoration practice for nearly ten years, I can tell you it was not too long ago that many physicians were reluctant to even acknowledge that photomedicine and Laser Therapy were viable treatment options. Today, with the increase in numbers of devices FDA-cleared for wound healing, pain control, facial rejuvenation and hair growth more and more physicians are working with laser and LED light sources and understanding more about what they can and cannot do. One of the most important things I have learned from administering and prescribing thousands of laser therapy treatments for hair growth is that without the 'target organ' (the hair follicle!) the treatment will not succeed. LLLT seems to improve the functioning of the skin including the hair follicles that are present and this is what creates the satisfying results for patients over months. However, if there are areas where hair follicles are severely depleted, these areas are unlikely to respond. As we always say, therefore, early treatment is the best treatment! Sincerely, Alan J. Bauman, M.D. / Certified, American Board of Hair Restoration Surgery
