Low-level laser therapy

A low level laser is shone directly on the scalp to stimulate hair growth through "Photo-Biostimulation" of the hair follicles. One product of these low level laser therapies is the Hairmax Lasercomb. There is no peer-reviewed evidence to support this claim. There is some debate over the FDA's acknowledgment of the Lasercomb, but it has been accepted by the FDA as effective in the submitted claims.
The HairMax LaserComb is a Laser Photo Therapy (LPT), medical device to treat androgenetic alopecia in males. The developing company, Lexington International, LLC., is located in Boca Raton, Florida.
The HairMax LaserComb utilizes 655nM lasers to stimulate the scalp and energize hair follicles. The primary science behind this process is known as PhotoBioStimulation. It is hypothesized that the HairMax LaserComb’s red laser energy is absorbed by chromophores inside cells of the hair follicle leading to an increase in cellular metabolism. This in turn leads to an increase in cell replication in epithelial portions of the hair follicle.
By promoting an increase in cell proliferation within the hair matrix, a new anagen phase is initiated. This new anagen phase causes premature shedding of Catagen and Telogen hairs. These hairs are subsequently replaced by a healthier, thicker new anagen hair.
The HairMax LaserComb was designed in Australia in the late 1990s. The developmental goal for the device was to provide laser therapy for hair loss and thinning hair for users in the convenience of their own home. Before its introduction, Laser Therapy was commonly delivered using large devices called Laser Hoods that utilized very large arrays of lasers. These devices limited users seeking laser hair treatments to visit a doctor’s office or laser clinic.
The HairMax LaserComb was cleared by the FDA as being "substantially equivalent" to predicate devices legally marketed before May 28, 1978. This clearance is not the same as approval because it only applies to the lasercomb and not to any other similar laser based hair devices. The devices that the lasercomb proved itself equivalent to were a variety of FDA approved laser based/non hair growth devices intended for hair removal and pain relief, and two non FDA approved non laser based/hair growth devices such as the Raydo & Wonder Brush and the Vacuum Cap.
These last two devices were sold in the early 1900s and are well established as medical quackery, but they were legal to market at the time which does satisfy the FDA's 510k SE criteria. The 510k number for the Lasercomb is K060305.
The Leimo laser was recently approved by the TGA (Therapeutic Goods Administration) of Australia as a Class IIa Medical Device. It was approved for safety but not for efficacy of results. The company is advertising that this unit is TGA approved to grow hair, which is false.