# NOW KSM-66 Ashwagandha 600 mg review: 90 capsules and safety checks Canonical: https://supplementexplained.com/products/now-ksm-66-ashwagandha-600-mg-90-capsules/ Last modified: 2026-10-15T07:36:50+00:00 Publisher: Supplement Explained Review model: Editorial review; medical review only when explicitly documented on the canonical page. The [NOW KSM-66 90-capsule bottle](https://www.nowfoods.com/products/supplements/ksm-66-ashwagandha-veg-capsules) provides 600 mg of organic ashwagandha root extract per vegetarian capsule. It is not a proven anxiety medicine, and ashwagandha is not suitable for everyone. Avoid ashwagandha during pregnancy or breastfeeding; [NCCIH also does not recommend it](https://www.nccih.nih.gov/health/ashwagandha) for people with thyroid or autoimmune disorders. Check with a clinician before use if you have surgery planned or take medicines, especially blood pressure, diabetes, thyroid, sedative, antiseizure or immunosuppressant drugs. Stomach upset and drowsiness can occur, and rare liver injury has been reported. Stop taking it and seek prompt medical care if you develop yellow skin or eyes, dark urine, or feel severely ill. Safety beyond about three months is uncertain. [NOW Foods products and brand analysis](https://supplementexplained.com/brands/now-foods/) ![NOW Foods KSM-66 Ashwagandha 600 mg, 90 vegan capsules; root extract](https://supplementexplained.com/wp-content/uploads/2026/10/se-backlog-r08.webp) ## NOW Foods KSM-66 Ashwagandha 600 mg Review the exact formula and label limits before ordering. [Check price at HerbsPro](https://www.anrdoezrs.net/click-101886474-15733504?sid=se-r08-20261015&url=https%3A%2F%2Fwww.herbspro.com%2Fproducts%2Fksm66-ashwagandha-325836) Affiliate link: we may earn a commission if you buy. **On this page** 1. [What this formula contains](https://supplementexplained.com/products/now-ksm-66-ashwagandha-600-mg-90-capsules/#what-this-formula-contains) 2. [What the research supports](https://supplementexplained.com/products/now-ksm-66-ashwagandha-600-mg-90-capsules/#what-the-research-supports) 3. [Price per capsule](https://supplementexplained.com/products/now-ksm-66-ashwagandha-600-mg-90-capsules/#price-per-capsule) ## What this formula contains The [NOW product page](https://www.nowfoods.com/products/supplements/ksm-66-ashwagandha-veg-capsules) does not state a withanolide percentage. The 600 mg figure describes the weight of the root extract, not its withanolide content. Other listed ingredients are hypromellose, microcrystalline cellulose, ascorbyl palmitate and silica. This is a different preparation from NOW's different 450 mg standardized formula. The milligram amounts alone do not tell you which delivers more withanolides. To match this exact product at a seller, look for NOW KSM-66, 600 mg, 90 vegetarian capsules and UPC 733739046338. Other brands' KSM-66 products, different bottle sizes and melatonin blends are separate products. ## What the research supports [NCCIH's evidence summary](https://www.nccih.nih.gov/health/ashwagandha) says some ashwagandha preparations may help with stress and insomnia, but studies are often small and limited. Those findings concern particular preparations; they are not results from a clinical trial of this finished NOW retail bottle. The KSM-66 trademark identifies a branded extract. The name alone does not establish that an individual batch has been independently tested. For more on the herb's potential benefits and risks, see our [ashwagandha guide](https://supplementexplained.com/supplements/ashwagandha/). ## Price per capsule The [matched HerbsPro listing](https://www.anrdoezrs.net/click-101886474-15733504?sid=se-r08-20261015&url=https%3A%2F%2Fwww.herbspro.com%2Fproducts%2Fksm66-ashwagandha-325836) was $18.41 for 90 capsules on October 15, 2026, before tax and shipping. That works out to about 20.5 cents per capsule. This is a per-capsule cost, not a confirmed daily cost: the bottle count alone does not establish a 90-day supply. ## Sources - [NOW exact KSM66 US label](https://www.nowfoods.com/products/supplements/ksm-66-ashwagandha-veg-capsules) - [NCCIH evidence and safety](https://www.nccih.nih.gov/health/ashwagandha) - [HerbsPro product listing (checked October 15, 2026)](https://www.herbspro.com/products/ksm66-ashwagandha-325836) Sources and labels checked October 15, 2026. [How we review](https://supplementexplained.com/how-we-review-evidence/). General information, not personal medical advice. Our editorial assessment ## Supplement Explained Score **64**/100 90 vegan capsules; root extract Five equally weighted criteria. This is an editorial assessment, not customer stars, a clinical ranking or a measure of medical effectiveness. **Label clarity **4/5**** Root source, extract name and 600 mg amount are stated, but the checked manufacturer page does not publish a withanolide percentage; the review does not invent one. **Research relevance **3/5**** Some preparation-specific trials support stress/sleep outcomes, with limited small-study evidence. They do not verify this retail lot or establish treatment of an anxiety disorder. **Safety and cautions **2/5**** Pregnancy/breastfeeding avoidance, thyroid/autoimmune cautions, multiple medicine interactions and rare liver-injury reports materially restrict routine suitability. **Testing and quality checks **3/5**** KSM-66 identifies a named extract, not independent finished-bottle potency or contaminant certification. No matching lot report was verified. **Value for money **4/5**** The $18.41/90 offer is about $0.205 per capsule and has a simple one-capsule label serving; low price does not remove the clinical cautions. Based on published information, not personal use or laboratory testing by us. Missing testing documentation is not evidence of contamination. Where label versions remain unresolved, the points reflect that limitation rather than assuming a complete current formula. Reviewed 2026-10-15 · Method v2.0 · [How we assign points](https://supplementexplained.com/quality/supplement-explained-score/) **Sources behind this score** - [www.nowfoods.com](https://www.nowfoods.com/products/supplements/ksm-66-ashwagandha-veg-capsules) - [www.nccih.nih.gov](https://www.nccih.nih.gov/health/ashwagandha) - [www.herbspro.com](https://www.herbspro.com/products/ksm66-ashwagandha-325836)