Clinical evidence shows that standardized ashwagandha extracts, such as KSM-66, can statistically significantly lower blood cortisol levels (Della Porta et al., 2023; Pakhale et al., 2025). However, when it comes to perceived, subjective stress, the picture is less clear-cut - a more recent meta-analysis (Albalawi, 2025) confirmed a reduction in cortisol but found no significant effect on subjectively perceived stress as measured by the PSS scale. This means improvement can occur at the biochemical level, while subjective well-being does not always change to the same degree. The response is also individual and depends on the dose and duration of use - with this product (200 mg/day), it is reasonable to expect a more moderate effect than with the higher doses used in studies.

That's true - many positive studies on stress and cortisol have used between 250 and 600 mg of standardized extract per day, and a pilot study with KSM-66 even used 600 mg/day (Pakhale et al., 2025). The 200 mg dose in this product is therefore at the lower end of this range, which doesn't necessarily mean the product doesn't work, but rather that the effect at this dose may be less pronounced than with the higher doses used in research. If you're looking for a dose closer to what was used in clinical studies, you may - after consulting a doctor or pharmacist - consider taking two capsules per day or choose a product with a higher extract content per capsule.

In short-term use, KSM-66 has been shown in clinical studies to be well tolerated, with a rate of adverse effects comparable to placebo (Winther, 2026). However, long-term safety (use beyond 6 months) has not been well studied; rare but documented cases of liver damage have been associated mainly with higher doses (450-1350 mg/day) and prolonged use. At the recommended dose (200 mg/day), the risk is lower, but the rule stated by the manufacturer still applies - do not exceed the recommended dose, and pregnant women, breastfeeding mothers, and people with illnesses or on medication should consult a doctor before use.

KSM-66 is the patented name for a standardized ashwagandha root extract, obtained through water-based ('green chemistry') extraction at a 12:1 ratio, guaranteeing at least 5% withanolides - compounds associated with most of the attributed effects. Since it is made exclusively from root material, it avoids the risks associated with the plant's leaves, which can contain up to 20 times more potentially hepatotoxic compounds such as withaferin A (Winther, 2026). KSM-66 is also the form used in most clinical studies, including Pakhale et al. (2025), so it has the most available data on efficacy and safety compared to non-standardized root powder, where the content of active compounds is less predictable.