The use of low-level light for hair growth: Part I

Abstract

LLLT may be a promising treatment option for patients who do not respond to either finasteride or minoxidil, and who do not want to undergo hair transplantation. This technology appears to work better for some people than for others. Factors predicting who will most benefit are yet to be determined. Larger, longer-term placebo-controlled studies are needed to confirm these findings, and demonstrate statistical significance, or refute them altogether.

Cosmetic Procedures in the Treatment of Alopecia

“…In a clinical study, seven patients with a diagnosis of AGA were exposed to LLLT twice weekly for 20 min for 3-6 months. An increase in the number of terminal hair, a decrease in the number of vellus hair, and an increase in shaft diameter were observed in this study but these changes were not statistically significant [89].…”

“…It is not exactly known, how these light sources can induce hair growth. One possible mechanism is the activation of silent hair follicles or the synchronization of hair growth cycles by direct light stimulation [89]. Radmanesh et al identified different mechanisms for developing hypertrichosis after the IPL.…”

“…The exact mechanism of photobiomodulation that stops or reduces hair loss in patients is not well known [85,89]. Low-level visible light treatment (LLLT) modulates the gen expression of 5α-reductase and vascular endothelial growth factor (VEGF) and consequently stimulates hair growth through androgen metabolism and angiogenesis [90].…”

Narrow-band red LED light promotes mouse hair growth through paracrine growth factors from dermal papilla

“…Sevaral clinical reports [1][2][3] have suggested that hair growth is promoted by low-level laser therapy (LLLT), defined as therapy using red-beam or near-infrared laser with a wavelength of 600-1100 nm and an output power of 1-500 mW, since Mester et al [4] reported effect of LLLT on hair growth in 1967. However, the irradiation area of laser system is small, and most systems are expensive and relatively immobile.…”

Androgenetic Alopecia: a Review and Emerging Treatments

“…Avram MR, et al [115] performed a study in 7 patients to investigate the efficacy of LLLT in hair regrowth and found a not statistical significance decrease in the number of vellus hairs, an increase in the number of terminal hairs, and an increase in shaft diameter. No improvement in hair density was noted.…”