Ashwagandha Root Extract (KSM-66)
Also known as: KSM-66, Withania somnifera root extract, KSM66
A branded, root-only ashwagandha extract standardized to at least 5% withanolides. It is the most studied ashwagandha ingredient, with trials on perceived stress, cortisol, sleep quality, and strength in resistance-trained adults. It is the default choice when a formula needs a clinically backed adaptogen.
Research summary
Withanolides appear to modulate the HPA axis and GABAergic signaling, reducing cortisol response to stress.
Dosage
Daily amounts, of extract.
| Lowest studied | Typical range | Highest studied | Upper limit |
|---|---|---|---|
| 250 mg | 300–600 mg | 1,250 mg | — |
Most trials use 300 mg twice daily or 600 mg once daily for 8 weeks or longer; benefits build over weeks rather than hours. Often taken with food. Some users report drowsiness, so evening dosing is common in sleep formulas.
Standardization: ≥5% withanolides (HPLC), root-only
Source material: root extract
Forms of Ashwagandha
| Form | Typical dose | Element % | Formats | Price |
|---|---|---|---|---|
| Ashwagandha Root Extract (KSM-66) | 300–600 mg | — | Capsule, Powder, Tablet, Gummy | high |
| Ashwagandha Root Extract (≥5% Withanolides) | 300–600 mg | — | Capsule, Powder, Tablet, Gummy | mid |
| Ashwagandha Leaf & Root Extract (Sensoril) | 125–250 mg | — | Capsule, Powder, Tablet, Gummy | high |
Format suitability
- Capsule
- Powder
- Tablet
- Softgel
- Gummy
- Liquid
Earthy, bitter taste; flavored powders and gummies usually need masking.
Formulation notes
Frequently paired with magnesium and L-theanine in stress and sleep formulas.
- Not for pregnancy
- Restricted in some countries
Sources
- 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. (Chandrasekhar 2012)PubMed
- An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: A randomized, double-blind, placebo-controlled study. (Lopresti 2019)PubMed
- Ashwagandha — ExamineExamine
- KSM-66 Ashwagandha — Ixoreal BiomedSupplier
Related ingredients
Ashwagandha Root Extract (≥5% Withanolides)
BotanicalA generic, non-branded ashwagandha root extract standardized to at least 5% withanolides.
Typical: 300–600 mg
L-Theanine
Amino acidAn amino acid found naturally in green tea that promotes a calm, focused state without sedation.
Typical: 100–200 mg
Ashwagandha Leaf & Root Extract (Sensoril)
BotanicalA branded water-extracted ashwagandha made from both leaf and root and standardized to a minimum of 10% withanolide glycosides, which lets it work at a smaller dose than root-only extracts.
Typical: 125–250 mg
5-HTP (5-Hydroxytryptophan)
Amino acidThe immediate precursor to serotonin, extracted commercially from Griffonia simplicifolia seeds.
Typical: 50–300 mg
Chamomile Flower Extract
BotanicalAn extract of German chamomile flowers standardized to apigenin, the flavone behind much of its calming reputation.
Typical: 220–1,100 mg