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evidence · mechanism · dose
Supplements/Herb

KSM-66 Ashwagandha

Root-only standardized ashwagandha extract — the most-studied form for stress and T-support.

Cortisol ManagementTestosterone SupportAthletic PerformanceSleep & Recovery

Overview

Root-only standardized ashwagandha extract — the most-studied form for stress and T-support.

Natural sources
    Common forms

      Forms & variants of Ashwagandha

      Different chemical forms of Ashwagandha behave differently. Browse each form's mechanism, bioavailability, and best-use context.

      Parent
      Ashwagandha

      Adaptogenic herb that down-regulates HPA-axis output — lowers cortisol, supports T in stressed men.

      Sensoril (root + leaf)
      Sensoril Ashwagandha

      Root + leaf extract standardized to ≥10% withanolides — higher potency, more sedating.

      Strength protocol (600 mg)
      Ashwagandha (Strength)

      KSM-66 dose for resistance training adaptations.

      Mechanism of action

      Standardized to ≥5% withanolides from root only (no leaf). Modulates HPA axis and GABAergic tone.

      Pathways
      • · HPA-axis dampening
      • · GABA mimetic
      • · Hsp90 modulation

      Effects on the body

      Organ system effects

      Evidence-based benefits

      Lowers cortisol ~28% in chronically stressed adults

      Moderate evidence

      Raises total testosterone in overweight/aging men

      Moderate evidence

      Potential side effects

      Common
      • · Drowsiness
      Rare
      • · GI upset
      Serious
      • · Liver injury (rare case reports)

      Drug interactions

      Thyroid hormone
      May raise T4 — monitor TSH.
      moderate

      Safety & non-supplemental interactions

      Educational summary — always confirm with your clinician or pharmacist before starting, stopping, or combining with prescription therapy.

      Avoid if you are
      • ·Pregnant or breastfeeding (insufficient safety data)
      • ·Children under 18 (unless directed by a clinician)
      Avoid with these conditions
      • ·Hormone-sensitive cancers (breast, prostate, ovarian, uterine)
      Avoid / monitor with these medications
      • ·Hormonal contraceptives, HRT, tamoxifen, aromatase inhibitors
      • ·Alcohol, benzodiazepines, opioids, sedating antihistamines (additive CNS depression)

      Supplement interactions

      Pairs well with

      None listed.

      Avoid combining with

      No specific avoidances listed.

      Dosing & bioavailability

      Typical dose
      300–600 mg
      Study range
      250–1250 mg
      Timing
      Morning or split
      With food?
      Optional

      Where to buy

      Affiliate-style search links to reputable retailers. We don't endorse specific brands — verify third-party testing (USP, NSF, Informed Sport) before purchase.

      Herb
      KSM-66 Ashwa…
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      iHerb
      Global delivery · curated brands
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      Thorne
      Practitioner-grade · NSF tested

      Scientific evidence (9)

      RCTIndian J Psychol Med · 2012

      KSM-66 ashwagandha for stress and cortisol

      Chandrasekhar K, et al.

      60-day RCT of KSM-66.

      Key findings

      Significant reduction in cortisol and stress scores.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: KSM-66 Ashwagandha — Lowers cortisol ~28% in chronically stressed adults

      Live PubMed search

      Live results for "KSM-66 Ashwagandha Lowers cortisol ~28% in chronically stressed adults" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching KSM-66 Ashwagandha and "Lowers cortisol ~28% in chronically stressed adults". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: KSM-66 Ashwagandha — Raises total testosterone in overweight/aging men

      Live PubMed search

      Live results for "KSM-66 Ashwagandha Raises total testosterone in overweight/aging men" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching KSM-66 Ashwagandha and "Raises total testosterone in overweight/aging men". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: KSM-66 Ashwagandha — randomized controlled trial

      Live PubMed search

      Live results for "KSM-66 Ashwagandha randomized controlled trial" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching KSM-66 Ashwagandha and "randomized controlled trial". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: KSM-66 Ashwagandha — meta-analysis

      Live PubMed search

      Live results for "KSM-66 Ashwagandha meta-analysis" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching KSM-66 Ashwagandha and "meta-analysis". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: KSM-66 Ashwagandha — pharmacokinetics

      Live PubMed search

      Live results for "KSM-66 Ashwagandha pharmacokinetics" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching KSM-66 Ashwagandha and "pharmacokinetics". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: KSM-66 Ashwagandha — safety adverse events

      Live PubMed search

      Live results for "KSM-66 Ashwagandha safety adverse events" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching KSM-66 Ashwagandha and "safety adverse events". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: KSM-66 Ashwagandha — dose response

      Live PubMed search

      Live results for "KSM-66 Ashwagandha dose response" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching KSM-66 Ashwagandha and "dose response". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewGoogle Scholar · 1970

      Google Scholar: KSM-66 Ashwagandha — clinical evidence

      Live Scholar search

      Cross-database citation index for KSM-66 Ashwagandha as it relates to "clinical evidence".

      Key findings

      Includes preprints, theses, and journal articles. Useful for tracking citation counts and follow-on work.

      Open study
      Educational use only. This profile is not medical advice. Consult a qualified healthcare professional before starting any supplement, especially if you take prescription medication or have a chronic condition.