KSM-66 (Ashwagandha extract)
Branded, root-only, full-spectrum extract of ashwagandha (Withania somnifera) standardized to withanolides; used in supplements and some functional foods.
Should I eat KSM-66 (Ashwagandha extract)?
KSM-66 is a standardized ashwagandha root extract with promising evidence for stress and sleep support at supplement-level doses. Most people tolerate it, but rare liver and thyroid effects and possible milk traces mean you should choose products carefully and stop use if concerning symptoms appear.
Summary
Clinical studies with standardized root extracts, including KSM-66, show moderate evidence for lowering perceived stress and improving sleep, with some support for resistance training gains. Effects depend on dose and extract; many trials use about 300 mg twice daily, whereas U.S. food products typically contain 25–80 mg per serving under self-affirmed GRAS. Safety in short-term trials is generally good, but rare case reports describe liver injury and thyrotoxicosis. In Great Britain, ashwagandha is permitted in supplements, while non-supplement foods require novel food authorization. Some full-spectrum versions use milk pre-treatment; vegan KSM-66 avoids this.
Key Research Benefits
Stress reduction and lower cortisol
Multiple human trials with standardized root extracts report reduced perceived stress and, in some studies, lower cortisol (a stress hormone).
Sleep quality
Several clinical studies suggest improved sleep quality and time to fall asleep with standardized extracts.
Exercise performance
Randomized trials in adults doing resistance training report greater gains in muscle strength and size versus placebo.
Key Research Risks
Liver injury (rare)
Uncommon cases of cholestatic or mixed-pattern liver injury have been reported with ashwagandha products, typically weeks after starting.
Thyroid effects
Case reports link ashwagandha to thyrotoxicosis or painless thyroiditis; caution if you have thyroid disease or use thyroid medication.
Processing-related dairy traces
Full-spectrum versions may be pre-treated with milk, which can introduce milk constituents; vegan KSM-66 avoids this step.
Food dose vs. studied dose mismatch
Self-affirmed GRAS allows 25–80 mg per serving in certain foods, while many trials use around 300 mg twice daily—so food amounts may be below studied levels.
Overview
What is it?
Why is it used?
Origin
Ashwagandha has been used for centuries in Ayurvedic medicine across India as a ‘rasayana’ (rejuvenator). KSM-66 is a modern, standardized, root-only extract commercialized by Ixoreal Biomed; the company promotes a proprietary solvent-free process and large clinical program. Some full-spectrum versions are traditionally pre-treated with milk, while a vegan variant omits milk.
Process: Aqueous extraction and purification (root-only)
Steps
Chemicals
Research & Safety
Potential Concerns
Serious side effects are uncommon but include rare liver injury; stop use and seek medical care if you notice jaundice, dark urine, pale stools, or severe fatigue. Isolated reports link ashwagandha with thyrotoxicosis; people with thyroid disease or on thyroid medication should use caution and monitor symptoms such as palpitations or heat intolerance. Some full-spectrum KSM-66 products are pre-treated with milk, which may introduce milk constituents; vegan options avoid this step—check labels. Effects vary across extracts and doses, and food products may contain much less than amounts tested in many clinical trials.
Potential Benefits
This extract does not supply meaningful calories, protein, or vitamins; its value is functional. Human studies with standardized root extracts suggest it can help reduce perceived stress and sometimes lower cortisol, a stress hormone that can disturb sleep and mood when chronically high. Several trials indicate better sleep quality and faster sleep onset. In people doing resistance training, some studies report greater gains in strength and muscle size compared with placebo. Benefits appear dose- and extract-dependent, with many trials using about 300 mg twice daily.
Digestive Effects
At typical supplemental intakes (often around 300 mg twice daily in studies), some people report mild digestive upset, nausea, or diarrhea. These symptoms are usually transient and dose-related. People with sensitive GI tracts or underlying digestive conditions may be more prone to discomfort. If you experience persistent GI symptoms, discontinue use and consider discussing with a clinician.
Limit Consumption
Avoid during pregnancy and breastfeeding due to limited human safety data. Not recommended for infants. People with thyroid disorders or on thyroid medications should use caution because case reports describe thyrotoxicosis with ashwagandha; discontinue and seek medical advice if symptoms arise. Those with liver disease or a history of drug-induced liver injury should consult a clinician first, as rare liver injury has been reported with ashwagandha products. If you need to avoid dairy, choose KSM-66 versions that explicitly state they are vegan (no milk pre-treatment).
Fact Sheet
Regulatory Status
ESG & Sustainability
Allergens and Diet
Natural Alternatives
Tulsi (holy basil)
Chamomile
L-theanine (green tea)
Citations
A double-blind RCT of ashwagandha root extract reducing stress and cortisol
2012-12-01Chandrasekhar K, Kapoor J, Anishetty S • PubMed
Withania somnifera improves muscle strength and recovery (RCT)
2015-11-01Wankhede S, et al. • PubMed
Effects of Withania somnifera on stress and mental health (systematic review)
2021-12-01Speers AB, et al. • PMC
Ashwagandha-induced liver injury—case report
2023-03-01Lubarska M, et al. • PMC
Ashwagandha as a cause of thyrotoxicosis (case report)
2022-05-01Kamal HI, et al. • PMC
KSM-66 achieves self-affirmed GRAS status (25–80 mg/serving in specific foods)
2012-09-13Staff • Nutraceuticals World
Ashwagandha—status for foods vs supplements in Great Britain
2024-05-01FSA • UK Food Standards Agency
What is KSM-66? (root-only, solvent-free claim)
2025-01-01Ixoreal Biomed • KSM-66 brand site
Disclosure of milk pre-treatment (Full Spectrum) and vegan version
2024-10-01Triibe Organics • Triibe Organics
KSM-66 300 mg twice daily—sleep study protocol
2023-05-01ClinicalTrials.gov • ClinicalTrials.gov