Primary Research · 2019
An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract
Lopresti et al. · Medicine, 2019
Key finding
240mg/day high-concentration extract produced significant cortisol and stress-score reductions at 60 days.
Abstract
PubMed · PMID 31517876 →BACKGROUND: Ashwagandha (Withania somnifera (L.) Dunal) is a herb traditionally used to reduce stress and enhance wellbeing. The aim of this study was to investigate its anxiolytic effects on adults with self-reported high stress and to examine potential mechanisms associated with its therapeutic effects. METHODS: In this 60-day, randomized, double-blind, placebo-controlled study the stress-relieving and pharmacological activity of an ashwagandha extract was investigated in stressed, healthy adults. Sixty adults were randomly allocated to take either a placebo or 240 mg of a standardized ashwagandha extract (Shoden) once daily. Outcomes were measured using the Hamilton Anxiety Rating Scale (HAM-A), Depression, Anxiety, and Stress Scale -21 (DASS-21), and hormonal changes in cortisol, dehydroepiandrosterone-sulphate (DHEA-S), and testosterone. RESULTS: All participants completed the trial with no adverse events reported. In comparison with the placebo, ashwagandha supplementation was associated with a statistically significant reduction in the HAM-A (P = .040) and a near-significant reduction in the DASS-21 (P = .096). Ashwagandha intake was also associated with greater reductions in morning cortisol (P < .001), and DHEA-S (P = .004) compared with the placebo. Testosterone levels increased in males (P = .038) but not females (P = .989) over time, although this change was not statistically significant compared with the placebo (P = .158). CONCLUSIONS: These findings suggest that ashwagandha's stress-relieving effects may occur via its moderating effect on the hypothalamus-pituitary-adrenal axis. However, further investigation utilizing larger sample sizes, diverse clinical and cultural populations, and varying treatment dosages are needed to substantiate these findings. TRIAL REGISTRATION: Clinical Trials Registry-India (CTRI registration number: CTRI/2017/08/009449; date of registration 22/08/2017).
Abstract sourced from PubMed, a database of the U.S. National Library of Medicine. Displayed in the authors’ own words for context; our critique is in the sections below.
Read the full paper
Cited in 3 guides
Review
Ashwagandha for Testosterone: What the Evidence Actually Shows
Ashwagandha shows modest but real testosterone effects in men — especially stressed or sedentary men. Here's how the mechanism works and whether you'll notice.
Guide
Ashwagandha Guide 2026: Clinical Evidence Reviewed
Learn which ashwagandha extract actually matches the RCT evidence — KSM-66, Sensoril, or generic powder — and what cortisol, anxiety, and testosterone data show.
Roundup
Best Adaptogens for Stress: Ashwagandha vs Rhodiola vs Reishi
Three of the most-studied adaptogens, compared head-to-head on clinical evidence, mechanism, and which one fits which stress profile.
How to read a study like this
The same questions worth asking about any research paper, not just this one. Worth a minute even if you trust the grade.
Who was studied, and do you resemble them?
Supplement effects often depend on baseline status. Vitamin D helps people who are deficient; iron helps people who are anemic. A result in people unlike you may not apply to you.
What was measured, and does it matter in daily life?
A study that shows a blood marker moved isn't the same as a study that shows people felt or functioned better. Ask what the outcome means in practice.
How large was the effect — not just whether it was significant.
'Statistically significant' only means the effect is unlikely to be zero. It doesn't tell you the effect is large enough to notice. Look for effect sizes, not just p-values.
Who paid for the trial, and what did they stand to gain?
Industry-funded trials are several times more likely to report positive results than independent ones. It's not usually fraud — it's subtle design and reporting choices. Weight accordingly.
Has anyone else replicated this?
Single positive trials are hypotheses. Replication by independent groups is what turns a hypothesis into reliable evidence. If the only positive trial is the one you're reading, wait.
Does the dose in the trial match what's being sold?
Supplement marketing routinely cites trials that used 5–10× the dose in the product. If the effective dose was 2 g/day and the capsule has 200 mg, expect roughly no effect.
About this page
Formulate maintains a registry of clinical studies cited across its guides and evidence grades. This page links the study metadata to the content that cites it — one canonical entry per landmark study.
The full citation chain is public so readers can verify claims without hunting through individual guide pages. Browse all cited studies →
Note: Study summaries on this page are editorial interpretations of the research. Always consult the primary source before drawing clinical conclusions.