2014

An Investigation into the Stress-Relieving and Pharmacological Actions of Ashwagandha

Pratte MA, Nanavati KB, Young V, Morley CP

Published in Journal of Alternative and Complementary Medicine

Abstract

Systematic review and meta-analysis demonstrating ashwagandha's efficacy in reducing stress and anxiety with good tolerability.

Methodology

Systematic review of human trials of Withania somnifera for anxiety; searched PubMed, SCOPUS, CINAHL and Google Scholar; 5 human trials met inclusion criteria (62 records screened).

Key Findings

All five included trials reported greater reductions in anxiety and stress scores with ashwagandha than with placebo or control. Effects were seen on validated scales including the Hamilton Anxiety Rating Scale and the Perceived Stress Scale. Doses varied widely across trials (roughly 125-12,000 mg/day of root extract or powder), and adverse events were infrequent and mild.

Conclusions

Ashwagandha shows consistent signals of benefit for anxiety and stress relative to placebo across small human trials, with good short-term tolerability. The authors concluded that results are promising but the evidence base is too small and heterogeneous to be definitive.

Limitations

Only five trials, all small and several at high risk of bias; wide variation in preparation, dose and outcome measures prevented pooled meta-analysis; most trials were short (6-12 weeks) and conducted in India, limiting generalisability.