Effects of Withania somnifera (Ashwagandha) Supplementation on Exercise Performance: A Systematic Review and Three-Level Meta-Analysis
Abstract
Background/objectives: Evidence for herbal ergogenic aids remains uncertain, and ashwagandha trials span heterogeneous performance domains. This review evaluated oral Withania somnifera supplementation on exercise performance and explored participant-, outcome-, formulation-, and supplementation-related moderators.
Methods: PubMed, Web of Science, Cochrane Library, Embase, and SPORTDiscus-EBSCO were searched from inception to 1 April 2026. Eligible randomized controlled trials compared oral ashwagandha with placebo or control conditions and reported objective exercise-performance outcomes. Dependent effects were synthesized using restricted-maximum-likelihood three-level random-effects models; 95% prediction intervals, GRADE certainty ratings, subgroup analyses, and dose/duration meta-regressions were reported.
Results: Thirteen trials involving 599 participants contributed 79 effect sizes. Samples were mainly young adults or athletes; reported ages included one 18-40-year trial and one late-adolescent athlete cohort aged 17.4 ± 1.7 years. Trial-level sex composition was four male-only, one female-only, three mixed-sex, and five incompletely reported cohorts. Ashwagandha improved overall exercise performance on average (Hedges' g = 0.47, 95% CI [0.25, 0.69], p 2 = 60%; 95% prediction interval [-0.40, 1.33]), but the prediction interval crossed zero. Exercise type was the clearest moderator (P_between = 0.006): evidence was most consistent for aerobic endurance (g = 0.54, 95%…
How strong is the evidence?
Evidence Hub reads this as a meta-analysis, done in people. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid. Reported size: 599 participants or records.
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