In theory, red light therapy or low-level light therapy (LLLT) works by using specific wavelengths absorbed by mitochondria to increase cellular energy, enhancing healing, blood flow and stem cell activation. In addition to building collagen and repairing damaged skin cells, this energy boost could also promote hair growth.

Dr. Kimberly S. Salkey, a board-certified dermatologist and the residency program director for the VCU School of Medicine's Department of Dermatology, said: "One theory suggests [red light therapy] impacts mitochondria inside hair follicles, ultimately leading to increased cellular energy and protein production. Another theory proposes that it triggers dilation of blood vessels leading to improved blood flow and decreased inflammation."