Application of red light therapy for moderate-to-severe acne vulgaris: A systematic review and meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 34363730 · doi:10.1111/jocd.14369
What was done
A systematic review and meta-analysis searched PubMed, Cochrane Library, EMBASE, and Web of Science for randomized controlled trials evaluating red light therapy for acne vulgaris. Primary outcomes were post-treatment improvements in average non-inflammatory and inflammatory acne lesions, as well as subtype lesion counts (comedones, pustules, papules, total lesions) compared against conventional treatment methods, alongside adverse events.
What was found
Across 13 RCTs with 422 total participants, red light therapy showed no statistically significant difference compared to controls in non-inflammatory lesion counts (WMD = -0.527; 95% CI, -3.055 to 2.001; p = 0.683) or inflammatory lesion counts (WMD = 0.701; 95% CI, -0.809 to 2.212; p = 0.363). Subgroup analyses of specific lesion types (comedones, pustules, papules, total lesions) also showed no significant superiority over conventional therapies (WMD = -1.125; 95% CI, -3.122 to 0.873; p = 0.270). Adverse events in the red light therapy arms were reported as mild or absent.
Why it matters
This review indicates that red light therapy does not outperform existing conventional acne treatments for lesion clearance, though it maintains a favorable side-effect profile.
Limits
The total sample size was small (averaging roughly 32 participants per trial), and the authors noted substantial study heterogeneity. The abstract did not report specific red light parameters (wavelengths, energy doses, treatment frequency) or long-term recurrence rates.