Abstract
Laser and light-based therapies including low-level laser and light therapy, fractional, excimer, and other lasers are increasingly well-regarded treatment options for patients with hair loss.
Lasers emit wavelengths of light specific to a chromophore in the tissue, causing a targeted thermal response with minimal damage to surrounding tissue. The cascade of events downstream of the initial injury is responsible for the clinical effects seen. Low-level laser or light therapy (LLLT) was accidentally discovered in the 1960s when Hungarian scientist Endre Mester attempted to repeat an experiment performed by American Paul McGuff, who had cured malignant tumors in rats using a ruby laser. Mester’s laser was much less powerful than McGuff’s, and while he did not successfully cure any tumors, he observed for the first time that a low-level laser induced hair growth and improved wound healing. The mechanism by which this occurs is described as photobiomodulation or the stimulation of biological processes in the target tissue. This accidental discovery is the basis for the huge variety of LLLT products available on the market today.
In the last 2 years alone, the number of approved items classified as laser, comb, or hair products intended for the purpose of the growth of scalp hairs on the FDA’s 510(k) premarket notification list, meaning the device is demonstrated to be at least safe and effective, has nearly doubled to a total of 50. This chapter will summarize current knowledge regarding all laser and light devices for patients with various forms of alopecia and will outline treatment strategy, device parameters, and appropriate limitations of use to guide providers toward optimal patient management.