Does Ashwagandha supplementation have a beneficial effect on the management of anxiety and stress? A systematic review and meta-analysis of randomized controlled trials
Systematic review of 12 RCTs (n=1,002) reports large random-effects standardized mean reductions in anxiety and stress with Ashwagandha versus placebo, but I² was very high (≈84–94%) and authors graded certainty of evidence low—formulations and populations varied.
Design
- Databases: PubMed/Medline, Scopus, Google Scholar through Dec 2021
- Included: 12 RCTs, n = 1,002 (25–48 y)
- Model: random-effects SMD with 95% CI
Pooled SMDs vs placebo (abstract)
- Anxiety: SMD −1.55 (95% CI −2.37 to −0.74; p = 0.005; I² ≈ 93.8%)
- Stress: SMD −1.75 (95% CI −2.29 to −1.22; p = 0.005; I² ≈ 83.1%)
Dose–response note
Abstract reports non-linear dose–response explorations favouring anxiety benefits up to very high labelled doses and a stress “sweet spot” around 300–600 mg/day in their model—read figures cautiously (certainty of evidence rated low).
Evidence hygiene
Heterogeneity, sponsorship, and scale diversity across trials mean headline SMDs are not guaranteed individual effects—pair with single-molecule psychiatric care when symptoms are severe.
Publication
Akhgarjand C, Asoudeh F, Bagheri A, et al. Phytother Res. 2022 Nov;36(11):4115–4124. PMID 36017529.
Outcomes
- Effect Size (Cohen's d / SMD)-1.55d (Cohen's d)
- Effect Size (Cohen's d / SMD)-1.75d (Cohen's d)