The question
Does light therapy help every kind of hair loss, or mainly one type?
What the researchers did
They reviewed 38 studies involving 3,098 people. Most participants—2,930—had androgenetic alopecia, commonly called pattern hair loss. They focused on hair density: how many hairs grow in a measured area.
What they found
Combined results favoured light treatment over placebo for pattern hair loss. Results varied widely between studies. The smaller groups with other causes of hair loss did not provide enough usable data for the same analysis.
What this means for a reader
The useful finding is specific: evidence for pattern hair loss should not be treated as evidence for every cause of shedding. The review does not identify one cap that works best.
One thing to take away
Before comparing devices, find out what kind of hair loss you have. A clinician can help with that question.
Read the paper
Perez SM et al. Dermatologic Surgery. 2025;51(2):179–183.
Low-Level Laser and LED Therapy in Alopecia: A Systematic Review and Meta-Analysis
PMID 39404126 · DOI 10.1097/DSS.0000000000004442
This note explains the published abstract. It is not a review of the full paper or personal medical advice. Published 1 November 2026.