Hair loss (alopecia) is a common disorder affecting more than 50% of the worldwide population. The most common type is Androgenetic alopecia and it affects around half of the male population over the age of 40 and 3/4th of the female population over 65. Minoxidil and finasteride are the only two drugs that are FDA approved. Hair transplantation is a surgical alternative.
It is known that red and near-infrared laser light aids tissue repair and regeneration. Also, low-intensity light called Low-Level Laser Therapy (LLLT) triggers cellular activity. LLLT for hair was discovered coincidentally when a mice irradiated with a low fluence red laser grew hair back in 1960.
It has been established through clinical trials that LLLT stimulates hair growth in both males and females. The main mechanism of action of LLLT is hypothesized to be the stimulation of epidermal stem cells in the bulge area of the hair follicle and transitioning of the follicles into the anagen phase.
LLLT seems to improve a variety of non-scarring alopecias—AGA (androgenic alopecia), AA (alopecia areata), and chemotherapy-induced anagen effluvium. LLLT is hypothesized to increase anagen hairs through NO (nitric oxide) release from CCO (cytochrome c oxidase) by photodissociation and LLLT also appears to reduce inflammation in AA (alopecia areata). A majority of studies investigating the effects of LLLT on hair growth employ wavelengths ranging from 635 to 650 nm. However, further studies are required to optimize treatment parameters and determine long-term efficacy as well as safety of LLLT.
LLLT has a very low incidence of adverse effects. Possible contraindications are the presence of dysplastic or malignant lesions on the scalp.