Research summary
KSM-66, Sensoril and Shoden: Extract Evidence
Limits of extract and supplement-form comparisons
The selected KSM-66, Sensoril and Shoden trials compared each studied formulation with placebo in different populations and protocols; they did not directly compare these three extracts with each other. The papers describe different plant-part preparations and standardization information, including total withanolides in KSM-66 and withanolide glycosides in Shoden. A higher printed percentage or a lower extract-milligram dose does not establish superior clinical results from these trials. Their findings cannot be transferred to an unstudied powder, tea, gummy or combination product.[1], [2], [3]
Clinical trials of ashwagandha have used a variety of preparations, and many have had small sample sizes. A finding for one studied preparation does not establish the same effect for every ashwagandha product. This summary does not rank extracts or establish that one brand is superior to another.[4]
What was actually studied
The selected KSM-66, Sensoril and Shoden trials compared each studied formulation with placebo in different populations and protocols; they did not directly compare these three extracts with each other. The papers describe different plant-part preparations and standardization information, including total withanolides in KSM-66 and withanolide glycosides in Shoden. A higher printed percentage or a lower extract-milligram dose does not establish superior clinical results from these trials. Their findings cannot be transferred to an unstudied powder, tea, gummy or combination product.[1], [2], [3]
The 2024 resistance-training trial studied KSM-66 ashwagandha root extract standardized to more than 5% total withanolides, at 300 mg twice daily for eight weeks in 80 active adults aged 18–45, with 73 included in efficacy analysis. This is the formulation and regimen of one training trial, not a general product recommendation, proof of strength improvement or evidence that all products labeled KSM-66 are equivalent.[1]
The 2025 postmenopause trial studied Sensoril aqueous ashwagandha extract from roots and aerial parts at 250 or 500 mg/day, divided morning and evening after meals for 24 weeks. The selected postmenopausal population and small groups do not establish a dose for other goals, equivalence to other preparations or safety over many months or years.[2]
The 2019 stress trial described Shoden as a standardized ashwagandha root extract, prepared using ethanol and water and containing 35% withanolide glycosides; 60 adults with mild stress took 240 mg once daily after dinner for 60 days. This describes the formulation in that paper, whose root-extract wording should not be assumed to identify the plant parts of every current Shoden product. Its milligrams and withanolide-glycoside percentage do not establish equivalence or superiority to differently standardized extracts.[3]
What standardization can and cannot tell you
The selected KSM-66, Sensoril and Shoden trials compared each studied formulation with placebo in different populations and protocols; they did not directly compare these three extracts with each other. The papers describe different plant-part preparations and standardization information, including total withanolides in KSM-66 and withanolide glycosides in Shoden. A higher printed percentage or a lower extract-milligram dose does not establish superior clinical results from these trials. Their findings cannot be transferred to an unstudied powder, tea, gummy or combination product.[1], [2], [3]
The 2019 stress trial described Shoden as a standardized ashwagandha root extract, prepared using ethanol and water and containing 35% withanolide glycosides; 60 adults with mild stress took 240 mg once daily after dinner for 60 days. This describes the formulation in that paper, whose root-extract wording should not be assumed to identify the plant parts of every current Shoden product. Its milligrams and withanolide-glycoside percentage do not establish equivalence or superiority to differently standardized extracts.[3]
Safety and medication context
NCCIH does not recommend ashwagandha for people with thyroid or autoimmune disorders or those who are about to have surgery. Discuss these conditions and any planned surgery with your healthcare professional before considering ashwagandha; supplement research does not justify changing prescribed care.[4]
Ashwagandha may interact with medicines for diabetes or high blood pressure, immunosuppressants, sedatives, anticonvulsants, and thyroid hormone medicines. Discuss possible interactions with your prescriber or pharmacist before use; do not stop, replace, or adjust prescribed medicines based on supplement information.[4]
References
- Effects of Ashwagandha ( Withania somnifera) standardized root extract on physical endurance and VO (2max) in healthy adults performing resistance training: An eight-week, prospective, randomized, double-blind, placebo-controlled study.. F1000Research. 2024. Randomized controlled trial View source →
- Ashwagandha and Shatavari Extracts Dose-Dependently Reduce Menopause Symptoms, Vascular Dysfunction, and Bone Resorption in Postmenopausal Women: A Randomized, Double-Blind, Placebo-Controlled Study.. Journal of menopausal medicine. 2025. Primary study View source →
- An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: A randomized, double-blind, placebo-controlled study.. Medicine. 2019. Randomized controlled trial View source →
- Ashwagandha: Usefulness and Safety. NIH National Center for Complementary and Integrative Health. Retrieved 2026-09-30. Government health fact sheet View source →
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How do ashwagandha extracts differ?
Ashwagandha (Withania somnifera) is an evergreen shrub used in traditional Ayurvedic medicine. Supplements may contain extracts of its root, leaf, or both.
Read FAQ →What matters when buying an ashwagandha supplement?
A product should be read in the context of its stated preparation and the research on that preparation. Different extracts and short-term trials limit conclusions about product effects and long-term safety.
Read FAQ →Compare products using the separate evaluation rubric
This research summary explains selection-relevant evidence. The comparison separately evaluates labels, testing, transparency, and other published criteria; it does not treat this evidence as proof that a ranked product works.