Low-level laser therapy (LLLT), also known as red light therapy or cold laser therapy, is thought to stimulate hair growth by irradiating photons into scalp tissue. These photons are absorbed by weak cells and may work in several ways to promote hair growth, including:
- Stimulating stem cells – LLLT may stimulate epidermal stem cells in the hair follicle bulge, which could shift the follicles into the anagen (growth) phase
- Increasing blood flow – LLLT may increase blood flow to the scalp through vasodilation, which can help distribute nutrients and oxygen to hair roots
- Stimulating metabolism – LLLT may stimulate metabolism in catagen or telogen follicles, which could lead to the production of anagen hair
- Preventing DHT buildup – LLLT may help prevent excessive buildup of dihydrotestosterone (DHT), the hormone responsible for male pattern hair loss