How it worked
One hundred people with pattern hair loss took part. Each person received real light on one side of the scalp and sham light on the other. Treatment lasted thirty minutes, three times weekly, for twenty-four weeks.
Why use two sides?
Comparing two sides of the same person helps reduce differences between participants. Researchers used scalp photographs, hair measurements and ratings to assess change.
What changed
At twenty-four weeks, the reported hair-coverage figures were 14.2% on the treated side and 11.8% on the sham side. Other hair measures also favoured treatment at the twelve- and twenty-four-week checks. No serious adverse events were observed.
What to remember
Both sides showed change, so the comparison matters more than a before-and-after photo alone. This study tests one treatment setup; it does not provide a universal schedule for every cap.
Read the paper
Fan SMY et al. Dermatologic Surgery. 2018;44(11):1411–1420.
Efficacy and Safety of a Low-Level Light Therapy for Androgenetic Alopecia: A 24-Week Trial
PMID 29957664 · DOI 10.1097/DSS.0000000000001577
This note explains the published abstract. It is not a review of the full paper or personal medical advice. Published 1 November 2026.