Can Red Light Therapy Regrow Hair? What the Clinical Trials Show

Androgenetic alopecia (male and female pattern hair loss) is one of the most common reasons people search for red light therapy in the first place. Unlike some wellness claims, this one has a reasonably deep bench of randomized, sham-controlled trials behind it — including FDA-cleared at-home devices.

What the research looked at

A 24-week, double-blind, sham-controlled trial randomized 40 people (20 men, 20 women) with androgenetic alopecia to either an active low-level laser helmet or a visually identical sham device, measuring hair density, hair diameter, and photographic assessment. Separately, a 2021 meta-analysis pooled seven double-blinded randomized trials of FDA-approved home-use low-level light and laser devices for pattern hair loss.

What they found

In the 24-week trial, the active-device group showed statistically significant improvements over sham in both hair density (p=0.002) and hair diameter (p=0.009). The pooled meta-analysis found a similarly clear, statistically significant increase in hair density across devices (standardized mean difference of 1.27), with laser-diode-only devices showing a larger effect than combined laser-and-LED devices.

What this means in practice

Across multiple independent, sham-controlled trials, light therapy consistently increases hair density in androgenetic alopecia — though results build gradually over months, not weeks, and mild scalp itching or temporary shedding were reported by some participants. It's most evidence-backed for early-to-moderate thinning rather than areas with long-term, complete hair loss.