Research synthesisLow evidenceSmall effect12 studies · 12 beneficial · 0 neutral · 0 harmful
Across 12 studies, all reported beneficial effects, with effect sizes ranging from small to moderate; the predominant effect size is small. The most robust evidence comes from a systematic review (n=1502) and a small randomized controlled trial (n=50) in adult atopic dermatitis patients using heat-killed and dried L-92 daily, which showed a statistically significant small beneficial effect on immune function. Study durations were not consistently reported, and no clear dose range emerges from the available data.
- Studied populations: adult atopic dermatitis patients
Caveats: Available evidence is overwhelmingly positive — clinical literature in this area is subject to publication bias (null-result studies are less likely to be published or indexed). Many of the included studies did not reach statistical significance — effect may be smaller than the predominant direction suggests. Evidence base is small (only 12 studies) — conclusions should be considered preliminary. Most studies are reviews with limited methodological detail, and only one RCT with a small sample size (n=50) reported significant results.
Generated Jun 11, 2026