Sensoril vs. KSM-66: Which Ashwagandha Extract?

Pick up a few ashwagandha bottles and two trademarks keep showing up: Sensoril and KSM-66. Both are branded extracts of the same plant, Withania somnifera. Both makers point to clinical trials. They are not the same product, and the trials behind one don’t vouch for the other.

This Sensoril vs. KSM-66 comparison covers what each extract is, which human trials tested it, at what doses, and who paid. The short version: none of the trials I found compared the two head to head, and the dose on your label tells you more than the trademark does.

A disclosure up front: this site earns commissions on CortiSync, a supplement whose label lists Sensoril. That’s a good reason to check what follows against the receipts.

What each extract is, according to its maker

The specifications in this section come from manufacturer and retailer material: a supplier brochure, patent summaries and product pages. None of it is peer-reviewed, and I couldn’t find a peer-reviewed source that checks these specifications. Read it as what each company says about its own product.

Sensoril

Sensoril was developed by Natreon and is now supplied by Kerry. Its supplier describes it as a patented, water-based extract of ashwagandha root and leaf, standardized to at least 10% withanolide glycosides. Search summaries of the patent describe a composition of at least 8% withanolide glycosides and sitoindosides and at least 25% oligosaccharides, with under 2% free withaferin A.

KSM-66

KSM-66 is made by Ixoreal Biomed. It’s marketed as a root-only, “full-spectrum” extract standardized to at least 5% withanolides, measured by HPLC. Its marketing describes a milk-based extraction with no alcohol or synthetic solvents.

Shoden, the third name in the studies

You’ll also see Shoden, from Arjuna Natural, in the research. It’s a root-and-leaf extract too, tested at 240 mg/day in stressed adults. In a trial in men aged 40 to 70 it delivered 21 mg of withanolide glycosides per day. So “root and leaf” isn’t unique to Sensoril.

Why “10% vs 5%” isn’t a scoreboard

It’s tempting to read the percentages as a ranking. Don’t. Sensoril’s figure is for withanolide glycosides and KSM-66’s is for withanolides, so the two numbers measure different things, and both come from the makers. A higher percentage on a spec sheet doesn’t tell you which extract does more in people. Only trials can do that, and the trials are what the rest of this article is about.

The human trials behind Sensoril

Sensoril’s stress evidence rests on two trials I could find, both manufacturer-linked, that each tested 125, 250 and 500 mg/day.

• Auddy 2008. This 60-day trial enrolled 130 chronically stressed adults in India, and 98 finished. The Sensoril groups were reported to have lower serum cortisol and C-reactive protein, lower stress-questionnaire scores and higher DHEA-S than placebo, with larger effects at higher doses according to secondary summaries. It appeared in a small nutraceutical-trade journal, isn’t indexed in PubMed, and search summaries report that the lead author worked for Natreon. Count it as company-funded.
• Pandit 2024. In an 8-week trial of chronically stressed adults in India, Sensoril was associated with dose-related falls in Perceived Stress Scale scores and in plasma cortisol, ACTH and salivary alpha-amylase compared with placebo. Improvements in sleep and vitality measures were also reported. The extract was reportedly prepared by Natreon India. Reported participant counts conflict, so I’m not quoting one.

Two other Sensoril studies are worth knowing, even though stress wasn’t their focus.

The STAR trial by Ziegenfuss and colleagues gave 38 recreationally active men aged 18 to 45 either 500 mg/day of Sensoril or placebo for 12 weeks, alongside supervised resistance training. Its main outcomes were strength and body composition, not stress or cortisol, so it isn’t covered here beyond safety: blood chemistries stayed normal. It was reportedly funded by a restricted grant from Natreon. It says little about stress in men over 40.

The other one is a safety signal from a small psychiatric trial of the same extract at 500 mg/day, so read it for what it is. A follow-up analysis by Gannon and colleagues looked at the few participants with abnormal thyroid values. All 3 who took the extract showed a rise in T4, while 6 of 7 on placebo showed a fall. That’s a tiny subset, but it’s Sensoril-specific safety data worth knowing, and a reason to check with a clinician if you have a thyroid condition. The trial registry entry names Sensoril.

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The human trials behind KSM-66

The maker and trade sources attribute three trials to KSM-66. All used a root-only extract.

• Chandrasekhar 2012. 64 adults with chronic stress at one hospital in India took 300 mg twice a day (600 mg/day) or placebo for 60 days. The extract group improved more on stress questionnaires and had a larger fall in serum cortisol. Funding wasn’t verified.
• Salve 2019. 60 stressed, healthy adults took 250 mg/day, 600 mg/day or placebo for 8 weeks. Both doses were associated with lower Perceived Stress Scale scores and serum cortisol than placebo, and better sleep quality. With about 20 people per group, the trial didn’t formally establish that one dose beat the other. The maker reportedly supplied the product.
• Verma 2021. A short safety trial in healthy young adults, below.

Verma is useful, but 8 weeks in 80 young, healthy volunteers can’t pick up rare problems like the liver reactions covered in the safety section below.

Sensoril vs. KSM-66, side by side

Two things jump out. Both extracts have small, short, mostly maker-linked stress trials pointing the same way: lower stress-questionnaire scores and lower cortisol than placebo. And none of the trials here compared the two directly, so a claim that one “beats” the other isn’t backed by these trials.

The Shoden column is there for one reason. Its trial in overweight men aged 40 to 70 found no cortisol difference from placebo, and that’s the closest match to this site’s readers of any trial here. More on that, and the meta-analyses, in what the ashwagandha trials actually show.

Dose is the part the label controls

The studied ranges are different. Sensoril’s stress trials used 125 to 500 mg/day. KSM-66’s trials used 250 to 600 mg/day. Those numbers aren’t interchangeable, because the extracts differ, so compare a label only with the doses tested for the extract it names.

The NIH Office of Dietary Supplements says that because trials used different preparations and doses, no specific extract or amount can be recommended. That’s the honest ceiling on any extract comparison, including this one.

Sleep adds a wrinkle. A meta-analysis of five trials found a small effect on overall sleep scores, stronger at 600 mg/day or more and over 8 weeks or more. That’s the top of KSM-66’s tested range and above the Sensoril doses tested. I couldn’t confirm which extracts its five trials used, so it isn’t a verdict on either brand. If sleep is the problem, the habits in why you keep waking up at 3am come first anyway.

For a real example: CortiSync’s label lists Sensoril at 300 mg per serving. Compare that with the 125, 250 and 500 mg/day groups in the Sensoril stress trials. Those trials are studies of Sensoril, the ingredient, on its own. For how the rest of that formula lines up with the doses studied, see my CortiSync review, which is an affiliate page and says so.

How to choose

Whichever trademark is on the bottle, here’s the checklist I’d run before buying:

1. The extract is named. “Ashwagandha root powder” or a bare “ashwagandha extract” tells you little about which trials apply.
2. The dose matches a studied dose for that extract. Per serving, not per bottle.
3. You know what else is in the capsule. Other herbs have their own evidence and their own doses.
4. You’ve cleared it with a clinician. More on why below.
5. You’ll give it 8 weeks and track one thing. Sleep, or a weekly stress score. Not a home cortisol test.

If you’re not sure whether a supplement should even be your first move, the Fade Score asks ten quick questions and points at the habits to fix first.

Safety is the same conversation for both

Sensoril and KSM-66 are both ashwagandha, so the same cautions apply. The ODS fact sheet describes ashwagandha as generally well tolerated for up to about 3 months, mostly with mild side effects such as loose stools, nausea and drowsiness, and notes a lack of long-term safety data. The NIH’s LiverTox entry describes rare cases of liver injury, typically 2 to 12 weeks after starting.

Thyroid is the other flag. Besides the Sensoril T4 finding above, a small trial of 600 mg/day of root extract in adults with subclinical hypothyroidism raised T3 and T4 and lowered TSH compared with placebo.

Talk to your clinician first, especially if you’re pregnant, take medication, or have a thyroid, liver or autoimmune condition. The full safety rundown, including the liver case series, is in the ashwagandha evidence article.

Bottom line

Per their makers, Sensoril is a root-and-leaf extract and KSM-66 is root-only. Sensoril was tested at 125 to 500 mg/day, KSM-66 at 250 to 600 mg/day. Both have small, short, mostly maker-linked trials showing lower stress-questionnaire scores and cortisol than placebo, and none of these trials compared the two directly.

The standardization percentages come from the makers and measure different things, so they don’t settle anything. What you can control is simpler: a named extract, a dose that matches what was studied for it, 8 weeks of patience, and a conversation with your clinician first.