How the two patented ashwagandha extracts differ in plant part, standardization and dose, and what each was actually tested for.
KSM-66 is a root-only extract standardized to 5% withanolides and usually taken at 300 to 600 mg a day; it has more trials, including strength and testosterone studies. Sensoril uses root and leaf, is standardized to over 10% withanolide glycosides and is studied at 125 to 500 mg a day, mainly for stress, cortisol and sleep. No trial has compared them directly, so choose based on your goal and the dose tested.
KSM-66 and Sensoril are both patented ashwagandha extracts, but they are made differently and dosed very differently. KSM-66, from Ixoreal Biomed, is made only from the root and standardized to 5% withanolides. Sensoril, developed by Natreon (now part of Kerry Group), is made from the root and the leaf and standardized to more than 10% withanolide glycosides.
In practice that means KSM-66 is usually taken at 300 to 600 mg a day, while Sensoril is studied at 125 to 500 mg a day, often 125 or 250 mg. Neither has been tested against the other in a head-to-head trial, so any claim that one is clearly better is marketing, not evidence.
| KSM-66 | Sensoril | |
|---|---|---|
| Maker | Ixoreal Biomed (India) | Natreon, now part of Kerry Group |
| Plant part | Root only | Root and leaf |
| Extraction | Water-based, described by its maker as "full-spectrum" | Water-based (aqueous) |
| Standardization | 5% withanolides (by HPLC) | Over 10% withanolide glycosides, plus withaferin A and oligosaccharides |
| Typical studied dose | 300 mg once or twice daily (300-600 mg/day) | 125, 250 or 500 mg/day |
| Main research focus | Stress, sleep, strength training, testosterone | Stress, cortisol, sleep quality, menopause |
Both companies say their extract is backed by many clinical studies, but the totals vary between their own marketing pages, so we have not quoted a number. What matters more is what each trial tested, below.
Traditional Ayurvedic use focuses on ashwagandha root, and KSM-66's makers highlight that their extract never uses leaves. The leaves contain more of certain withanolides, including withaferin A, which is one reason Sensoril reaches a higher withanolide percentage at a smaller dose.
Whether leaf extracts are as safe as root extracts is debated, and Sensoril's makers point to their own safety data. There is no study comparing the safety of the two extracts directly. For you, the practical point is that a "higher withanolide" number is not automatically better. It just means a different extract, and the right dose is whatever was studied for that extract.
KSM-66 has the bigger research portfolio, and it is the extract most testosterone and sports formulas use. Key trials include:
The limits are real. These trials were small, run mostly in India, and the extract was supplied by its manufacturer. The 2015 strength paper also contains inconsistencies between its abstract and its results. Our complete KSM-66 guide goes into its full research record.
Sensoril has fewer published trials, but its main recent study tested three doses against placebo, which is useful for picking an amount.
Sensoril does not have the kind of testosterone or strength-training trials that KSM-66 does. If those are your goals, KSM-66 has more direct evidence.
Supplement marketers often call KSM-66 the "energizing" option and Sensoril the "calming" one. We could not find a trial that compared the two for energy or sedation, so treat that as a rule of thumb at best. Both have shown benefits for stress and sleep in placebo-controlled trials, and both can cause drowsiness.
A more useful way to choose:
Whichever you choose, check that the label actually names the branded extract and gives the dose. Generic "ashwagandha root powder" is not the same as either.
Neither brand removes the general cautions that apply to ashwagandha. The NIH Office of Dietary Supplements and NCCIH list stomach upset and drowsiness as common, rare liver injury, possible effects on thyroid hormone, and possible interactions with sedatives, thyroid, diabetes, blood pressure and immunosuppressant drugs. It should be avoided in pregnancy, and it may not be safe for men with hormone-sensitive prostate cancer. Denmark banned ashwagandha in supplements in 2023 after a risk assessment. Long-term safety beyond about three months is not known. We cover this in detail in our guide to ashwagandha side effects in men.
KSM-66 is a root-only extract at 5% withanolides with the larger set of trials, including strength and testosterone studies, at 300 to 600 mg a day. Sensoril is a root-and-leaf extract at over 10% withanolide glycosides that has shown stress, cortisol and sleep effects at lower doses of 125 to 500 mg a day. Neither has been proven better than the other, and most of the research on both was funded or supplied by the companies that sell them. Pick based on your goal and the dose its trials used, not the withanolide percentage, and talk to your doctor first if you have a thyroid, liver or autoimmune condition or take regular medication.