Leach · Sleep medicine reviews 2015 · systematic review and meta-analysis of randomized controlled trials · n=14 RCTs (1602 participants)

Herbal medicine for insomnia: A systematic review and meta-analysis.

Level 1 - systematic review of randomized trials

Systematic review and meta-analysis of randomized controlled trials

PubMed 25644982 · doi:10.1016/j.smrv.2014.12.003 · record verified 2026-08-26

What was done

Authors conducted a systematic review and meta-analysis by searching 17 electronic databases and reference lists for randomized controlled trials (RCTs) evaluating herbal medicines for insomnia. Fourteen RCTs involving a total of 1,602 participants met inclusion criteria, examining four distinct oral herbal monopreparations: valerian, chamomile, kava, and wuling.

What was found

No statistically significant differences were found between any herbal medicine and placebo, or between any herbal medicine and active control, across any of the thirteen measures of clinical efficacy. Adverse events per person were similar to or lower than placebo for kava, chamomile, and wuling, whereas valerian showed a greater number of adverse events per person compared to placebo. The abstract reports no numerical effect sizes or confidence intervals.

Why it matters

Despite widespread public use of herbal supplements as sleep aids, current randomized trial evidence does not support the efficacy of these common monopreparations over placebo for treating insomnia.

Limits

The findings only apply to four specific single-herb preparations and cannot be generalized to multi-herb formulations or other botanicals. The abstract does not report numerical data, heterogeneity metrics, or risk of bias assessments for the included studies.

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