New clinical data on ashwagandha across dose, safety and scale

Ashwagandha is now one of the top-selling botanicals in the US, and with that visibility has come sharper scrutiny of its safety.

A growing body of clinical research on KSM-66 Ashwagandha – including a 12-month long-term study, a high-dose study, and a large multinational randomized controlled trial – directly addresses the questions formulators, regulators, and consumers are asking.

As ashwagandha has moved from niche adaptogen to mainstream wellness staple, the question facing brand owners has evolved. It is no longer only “does it work?” but “how confident can we be that it is safe at the doses consumers actually take, and over the timeframes they actually use it?”.

That question has become increasingly important amid growing discussion around the safety of ashwagandha products. For formulators, this has placed a sharper focus on traceability and manufacturing consistency.

KSM-66 Ashwagandha, one of the most clinically studied ashwagandha root extracts, has addressed this question through a structured body of safety-focused research. Three key studies now help anchor the evidence base, each addressing a different dimension of real-world use: duration, dose, and scale.

Three pillars: Duration, dose, and scale

Long-term use

In 2025, a prospective, multi-centre observational study published in Phytotherapy Research evaluated the long-term safety of KSM-66 Ashwagandha in healthy adults over a 12-month period.¹ Throughout the study, key hepatic, renal, and thyroid-related parameters remained within normal reference ranges, supporting the overall tolerability of the extract during extended use.¹

The study also reported that adverse events were mild and self-limiting, with no clinically relevant safety concerns attributed to the intervention. In addition to the safety findings, participants showed improvements in stress-related and quality-of-life measures, further supporting the extract’s suitability for long-term wellness applications.

High-dose evaluation

As concentrated botanical extracts become more common in the supplement market, dose-related safety has become an important consideration. A 2026 study published in Frontiers in Nutrition evaluated KSM-66 Ashwagandha at a dose higher than commonly used commercial levels.² The extract was well tolerated over the study period, with no serious adverse events reported.²

Importantly, liver-related parameters remained within normal reference ranges, and no clinically meaningful changes were observed in broader safety assessments, including kidney and thyroid-related markers.

Large-scale multinational trial

In 2026, a prospective, randomized, double-blind, placebo-controlled, multicenter study published in Phytotherapy Research evaluated KSM-66 Ashwagandha root extract in adults experiencing stress and anxiety across multiple international sites, including India, the US, Australia, Portugal, and Africa.³ The study assessed the safety and tolerability of 600 mg/day KSM-66 Ashwagandha root extract over an eight-week period.³

No serious adverse events were reported, and the extract was well tolerated, with an adverse-event profile comparable to placebo. Importantly, laboratory evaluations showed no clinically meaningful safety concerns, with liver-related parameters, renal markers and hematological indices remaining within normal reference ranges throughout the study.

Based on data from 1002 participants between 18 to 65 years, this study is one of the largest controlled safety datasets available for an ashwagandha root extract. This multinational RCT provides important reassurance for formulators, regulators and brand owners seeking evidence generated on KSM 66’s standardized, root-only extract.

Breadth across populations and applications

Beyond these three safety pillars, KSM-66 Ashwagandha has also been evaluated across a wide range of populations and wellness applications, including stress and weight management, healthy aging, frailty, male and female sexual health, hair and skin health, and sports performance.

A 24-week study in adults using 600 mg/day for stress and weight management found no clinically significant laboratory changes and only mild, self-resolving adverse events.⁴

Limited clinical data under controlled conditions have reported no adverse events within the duration and population studied – however these small studies are limited in size and do not override current regulatory advice which is to avoid ashwagandha during pregnancy and breastfeeding. A randomized trial in pregnant women conducted under clinical supervision reported no adverse events when KSM-66 was added to standard prenatal care, with stable hepatic, renal, cardiac, and thyroid markers.⁵

Further safety data spans male and female sexual health, healthy aging and frailty, hair and skin health, and body composition in professional athletes, where 600 mg/day for eight weeks was well tolerated with no effect on blood health indices.^{6 -11}

A strong safety dossier

KSM-66 is a root-only extract standardised to >5% total withanolides using HPLC, with key compounds such as withaferin A and withanone tightly controlled at low levels. Its manufacturing process is vertically integrated and uses a green-chemistry, solvent-free extraction approach under quality-controlled conditions.

For formulators, understanding the product they intend to use is standardized and backed by clinical studies is paramount. Data generated on one extract cannot automatically be applied to another product if the plant part, extraction method, standardization profile or quality controls are different.

KSM-66 now offers safety evidence across duration, dose and scale, supported by a broader clinical research program across multiple health areas. For brands operating in an increasingly scrutinized botanical market, that level of evidence provides a strong basis for product development, and consumer communication

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