Full profile
| Also known as | Withania somnifera, KSM-66, Sensoril |
|---|---|
| Best for | Resilience to everyday stress · Calm, non-stimulant focus under pressure · Sleep quality and next-day clarity |
| Evidence grade | Grade C — Limited — early or small human trials |
| Studied dose range | 300–600 mg/day standardized root extract (KSM-66 ≥5% withanolides; Sensoril 125–250 mg at ≥10% withanolide glycosides). |
| Time to effect | Cumulative — builds over roughly 4–8 weeks. |
| Best form | KSM-66 (root-only, largest trial base) or Sensoril (higher withanolide load at a lower dose). |
Evidence, honestly graded
60-day RCTs of 240–600 mg/day KSM-66 lowered perceived stress and serum cortisol versus placebo (Salve 2019; Lopresti 2019); direct cognition signals come from smaller trials and are not yet robust in healthy adults. Stress evidence is roughly B; the cognition grade is honestly C. A liver-safety signal caps the grade regardless of the stress-efficacy data: NIH LiverTox classifies ashwagandha as a "probable" cause of clinically apparent liver injury (likelihood score C), a 2023 case series documented ashwagandha-related liver injury — including deaths — in patients with underlying liver disease, and Australia's TGA issued a liver-safety alert in February 2024.
See the full grading rubric — study type, replication, population match, and dose adequacy — in The Evidence Standard.
Side effects
- Mild GI upset
- Drowsiness or sedation
- Rare but documented liver injury, including fatal cases in people with pre-existing liver disease
Who should avoid it or check first
- Pregnant or breastfeeding
- Any pre-existing liver condition — avoid given documented cases of serious, sometimes fatal, liver injury
- Thyroid disorders without review
- Autoimmune conditions or before surgery without review
Interactions
- May interact with thyroid medication, sedatives, immunosuppressants, and blood-pressure or diabetes medication — discuss with a clinician
Stacks well with
- Citicoline
- L-Theanine
- Phosphatidylserine
Use caution stacking with
- Rhodiola Rosea (activating adaptogen — directional mismatch with ashwagandha's calming profile)
What to look for on a label
- Health Canada permits adaptogen/stress and traditional-use wording; a modern focus/clarity claim is off-monograph.
- Carry a liver-precaution line and a pre-existing-liver-disease avoidance statement — the safety signal is now documented by a regulator (TGA) and a published case series, not just a general monograph note.
References
- Salve 2019, Cureus — KSM-66 stress/cortisol RCT. Reduced perceived stress and serum cortisol vs placebo in healthy adults. PMID 32021735; doi:10.7759/cureus.6466. Educational, not a product claim.
- Lopresti 2019, Medicine (Baltimore) — ashwagandha stress RCT. Stress-relief and cortisol reduction over 60 days. PMID 31517876; doi:10.1097/MD.0000000000017186. Educational, not a product claim.
- LiverTox — Ashwagandha (NIDDK, updated 2024). Classifies ashwagandha as a probable cause of clinically apparent liver injury (likelihood score C). Basis for the liver-precaution line. NCBI Bookshelf NBK548536.
- Case series — ashwagandha-associated liver injury (2023). Published case series in Hepatology Communications documenting ashwagandha-related liver injury, including deaths, in patients with underlying liver disease. Basis for the pre-existing-liver-disease avoidance statement. Educational, not a product claim.
- TGA safety alert — ashwagandha and liver injury (February 2024). Australia's Therapeutic Goods Administration issued a liver-safety alert for ashwagandha-containing products. tga.gov.au.
Primary citations for some entries above are still being compiled; those without a linked identifier are editorial summaries of the wider literature.
Grades and studied doses are our conservative reading of the human research, shown for education. They are not product claims, and a studied dose is not a recommended dose.
See how Ashwagandha compares on grade, dose, and goal in the Evidence Explorer.
