Ingredient Evidence Review
KSM-66 Ashwagandha
Withania somnifera (root extract)
Last updated 2026-05-19 · 3 primary citations
Mechanism
KSM-66® is the most clinically studied form of ashwagandha, an adaptogen that helps the body return to baseline after stress. Its most consistent effect across trials is lowering cortisol — the stress hormone — which is why it sits in the evening packet to help a high-output day actually wind down.
Why we use it
Post-high-stakes-day cortisol clearing — pairs with Reishi triterpenes for the PM cortisol wind-down. Root-only extract (not leaf, not isolate).
How we dose it
Hericea uses 600 mg per serving (per PM packet). The clinical trial range that anchors this dose is 300–600 mg/day.
Upper end of the standard adult KSM-66 dose. The controlled trials behind ashwagandha run 8–12 weeks at 240–600 mg; the only 12-month study is an observational safety study, not an efficacy trial. Nobody has shown in a controlled trial what a year of this does.
Quality & sourcing
KSM-66® full-spectrum root only; ≥5% withanolides; Ixoreal-licensed.
Root only — no leaf, no berry, no isolate.
Cautions
- avoidAvoid if you have autoimmune thyroid conditions or take thyroid medication.
- consult physicianConsult physician if pregnant or nursing.
Primary literature
Chandrasekhar et al. (2012)
Indian J Psychol MedRCT
KSM-66 reduced cortisol and perceived stress.
PMID 23439798
Choudhary et al. (2017)
J Diet SupplRCT
KSM-66 improved memory and cognitive function.
PMID 28471731
Salve J et al. (2025)
Phytother ResProspective observational study · 52 weeks
Twelve months of standardised ashwagandha root extract in healthy adults was well tolerated. This was a safety study — it was not randomised, not placebo-controlled, and did not measure cortisol.
The only 12-month human data that exists. It tells you the ingredient is tolerable for a year; it does not tell you it works for a year.
DOI 10.1002/ptr.70096