Primary Research · 2012
A prospective, randomized double-blind, placebo-controlled study of safety and efficacy of a high-concentration full-spectrum extract of ashwagandha root in reducing stress and anxiety in adults
Chandrasekhar K, Kapoor J, Anishetty S · Indian Journal of Psychological Medicine, 2012
Key finding
60-day double-blind RCT (n=64) using 300mg KSM-66 ashwagandha twice daily significantly reduced perceived stress (PSS) and serum cortisol vs placebo.
C
58/100
Methodology review
Formulate's editorial read of the paper's design, scope, and limitations.
Critique
Often cited as proof ashwagandha reduces stress, but the methodology limits how much weight this single trial can carry. n=64 is modest for detecting the reported effect size. 60 days is a short window for chronic stress claims. Outcomes were a subjective scale (PSS-14) plus a single morning serum cortisol draw — morning cortisol is highly variable day-to-day and is not a robust biomarker of chronic stress compared to diurnal curves or hair cortisol. The KSM-66 extract is manufactured by Ixoreal Biomed, whose involvement appears across many subsequent ashwagandha trials, complicating independent replication. The direction of results has been echoed in later trials, but any one small trial of this design is weak evidence on its own.
What would be more convincing
A 12-week pre-registered RCT with n≥200, independently funded, using diurnal or hair cortisol alongside PSS-14, with a pre-specified MCID on the PSS, would be materially more convincing.
Reviewed 2026-04-21 · Opinion based on verifiable facts in the published paper.
About the supplement
Ashwagandha
Dose · mechanism · evidence grade · safety →
Read the paper
Open on PubMedhttps://pubmed.ncbi.nlm.nih.gov/23439798/
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