Red Light Therapy for Scarring Hair Loss (Cicatricial Alopecia): Scientific Evidence

Among 16 women aged 60 to 74 with frontal fibrosing alopecia, a scarring hair loss that pushes the front hairline back, a 2021 clinical trial tested LED therapy for eyebrow loss. Red LED light at 625 to 635 nm was applied to both eyebrows and the front hairline from a distance of 5.91 inches, in 9.07-minute sessions given once a week for 10 weeks, at a fluence of 37 J/cm². The authors concluded that total eyebrow hair count, along with the number of thick and medium-thick hairs, increased significantly after 10 sessions, with the improvement described as cosmetically acceptable. The therapy was reported as well tolerated and safe.

A 2020 clinical trial examined low-level light therapy for scarring hair loss in 4 patients with lichen planopilaris, an inflammatory scalp disease that scars hair follicles. Red and near-infrared light, from about 625 to 970 nm, was applied to the scalp, and in some cases to the lining inside the mouth. Sessions ran roughly 2.5 to 20 minutes, 2 to 7 times per week. All 4 patients appeared to improve, with less inflammation, symptoms disappearing, and visible hair regrowth. No side effects were reported in these cases.

Researchers in Poland tested a red LED device as an add-on therapy for 16 women aged 41 to 76, 8 with frontal fibrosing alopecia (FFA), a scarring hair loss that pushes the front hairline back, and 8 with lichen planopilaris (LPP), an inflammatory scalp disease that scars hair follicles, in a 2019 clinical trial. The superluminescent LED delivered 630 nm red light once a week for 10 weeks, at an irradiance of 70 mW/cm² and a total dose of 44.45 J/cm² to the scalp. The study found that scores for how active the scalp inflammation was and for how severe the frontal fibrosing alopecia was both dropped significantly after treatment, and the number of thick hairs in the treated area increased, though medium and thin hair counts did not change. The therapy was described as well tolerated.