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Show your sourcesModerate evidenceReviewed May 2026

Ashwagandha reduces serum cortisol, the receipts.

Multiple RCTs show measurable cortisol reduction at 300 to 600 mg/day of standardized root extract over 4 to 8 weeks.

3 of 3 matching studies surfaced. NutriStack rating: moderate evidence. Last reviewed May 26, 2026.

How we tier evidence →Browse all claim deep dives

Moderate evidence, per the methodology. Strongest 3 studies linked to PubMed.
Recommendation, contrary evidence, and dose are all on this page.

The studies·Contrary evidence·Recommendation

The studies

Strongest evidence, sourced.

Sorted by study tier (meta-analyses first, then RCTs, then reviews) and recency. Every entry links to PubMed by PMID.

At a glance

Substances
Ashwagandha
Evidence tier
Moderate evidence
Strongest studies surfaced
3 of 3 matching
One-line verdict
Biochemically real, clinically modest.
Last verified
May 30, 2026

Top 3 studies

  1. RCT Majeed M, Nagabhushanam K, Mundkur L, Medicine 2023

    A standardized Ashwagandha root extract alleviates stress, anxiety, and improves quality of life in healthy adults by modulating stress hormones: Results from a randomized, double-blind, placebo-controlled study. PMID 37832082

    Standardized ashwagandha root extract significantly reduced cortisol levels and perceived stress while improving quality of life scores in healthy adults.

  2. RCT Chandrasekhar K et al., Indian J Psychol Med 2012 · n=64

    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 PMID 23439798

    300 mg twice daily for 60 days significantly reduced serum cortisol levels compared to placebo

  3. Meta-analysis Della Porta M, Maier JA, Cazzola R, Nutrients 2023

    Effects of Withania somnifera on Cortisol Levels in Stressed Human Subjects: A Systematic Review PMID 38140274

Contrary evidence

What pushes back.

Caveats, null findings, and methodological limits that hold the tier where it is.

What argues against the claim

  • Most trials are 8 weeks or shorter.
  • Effect on cortisol does not consistently translate to clinical depression or anxiety outcomes.
  • Rare but real hepatotoxicity has been reported.

Recommendation

What the evidence supports.

What we recommend, with caveats

300 to 600 mg/day of a standardized root extract (KSM-66 or Sensoril) for 4 to 12 weeks. Cycle off periodically; long-term hormonal effects are under-studied.

Tier criteria are documented at /methodology/evidence-tiers. Sourcing standards at /methodology/interactions.

Stack interaction risks

Where these substances clash.

Documented pairings involving the substances behind this claim. Cautions and conflicts come first.

Pairs in the database

Open the free interaction checker at /interactions to scan a full routine.

Goal hubs

Where this claim feeds in.

Goal-based hubs that index this claim alongside related supplements and protocols.

Related goal hubs

Before you go

One claim, opened up. NutriStack does this for every claim in the database.

The full library lives at /research. Every entry follows the same shape: the verdict, the studies, the contrary evidence, the recommendation, and the primary literature.

Browse all claim deep dives →Read the methodology

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