Low-Level Laser Hair Therapy

LLLT is most often discussed for androgenetic alopecia—the gradual, patterned thinning that affects both men and women. Devices come as caps, helmets, headbands, and handheld combs; some are used in clinics, while many are sold for home use. Several such devices have received FDA 510(k) clearance as low-risk devices for hair growth, but clearance of a device category is not the same as proof that a particular product will work for a particular person.

It targets follicles that are still alive but weakened and producing finer hair, not areas that have been smooth and bald for years, where follicles may no longer be viable. It does not create new follicles or move them—that is the domain of hair transplantation, a separate surgical procedure. Nor does it treat underlying causes of shedding such as thyroid disease or iron deficiency, which need their own diagnosis and care.

The approach is sometimes called photobiomodulation. Red to near-infrared light at low power is absorbed by cells in and around the follicle, and is thought to boost cellular energy production, improve local blood flow, and nudge resting follicles back toward the growth phase. Unlike the lasers used for hair removal, the energy is deliberately kept low: it does not heat, cut, or destroy tissue. Before starting, it makes sense to have the cause of hair loss properly diagnosed.