What Does the Research Say About Ashwagandha and Cortisol?

The research on ashwagandha and stress is more substantial than most adaptogens, and the signal is consistent: standardized ashwagandha root extract, particularly the KSM-66 form, is associated with meaningful reductions in perceived stress and anxiety in adults with chronic stress when taken daily for eight or more weeks. The evidence for supporting a healthy stress response is strong enough that the National Center for Complementary and Integrative Health has acknowledged it. The mechanism involves the HPA axis, the same system that governs cortisol production. 

What ashwagandha is and why it works in the stress context

Ashwagandha (Withania somnifera) is a root used for centuries in Ayurvedic medicine and classified as an adaptogen, a substance that supports the body's ability to maintain equilibrium under stress. Its active compounds, called withanolides, are believed to modulate HPA axis activity, influence GABAergic signaling, and reduce inflammatory signaling pathways that are activated under sustained stress.

A comprehensive review published in PMC via the National Institutes of Health found that clinical trials with standardized ashwagandha extracts have shown reductions in stress-related markers, along with improvements in cognitive performance, sleep quality, and mood parameters. The review notes that withanolides modulate the HPA axis and contribute to ashwagandha's adaptogenic and anxiolytic actions.

What the meta-analyses show

Multiple systematic reviews and meta-analyses have now examined ashwagandha's effects on stress and cortisol markers in randomized controlled trials. A 2024 meta-analysis published in PubMed searched four databases and included seven RCTs on cortisol and six on perceived stress, covering 488 participants. The analysis found that ashwagandha supplementation was associated with significant reductions in cortisol compared with placebo in the included studies.

A second systematic review and meta-analysis, published in BJPsych Open via PMC, included 15 studies with 873 participants and found that ashwagandha supplementation significantly reduced anxiety compared with placebo. The authors searched PubMed, Web of Science, Scopus, and Cochrane databases through September 2024 and included only randomized controlled trials conducted in adults with stress or anxiety.

It is worth being precise about how to interpret these findings. The research shows ashwagandha supplementation was associated with changes in stress and anxiety measures compared to placebo. This is a meaningful signal. It is not a claim that ashwagandha directly lowers cortisol as a drug would, and the studies varied in dose, duration, and extraction method. The most consistent findings come from standardized root extracts taken for at least eight weeks at doses of 300 to 600 mg per day.

"Sleep is… the king, the queen… of health."

— Dr. Samantha Ess, ND, Naturopathic Doctor specializing in hormone health and fertility

KSM-66 specifically: why the form matters

Not all ashwagandha supplements are equivalent. KSM-66 is a standardized root-only extract, meaning it is produced exclusively from the root of the ashwagandha plant rather than a root-and-leaf combination. This distinction matters because most of the clinical research showing positive outcomes has used root extracts or root-standardized products, and the root is the part of the plant with the longest documented use in traditional medicine.

The NIH Office of Dietary Supplements notes that ashwagandha studies showing meaningful sleep benefits used KSM-66 root extract at doses of 250 to 600 mg daily, with more prominent effects at 600 mg and after at least eight weeks of consistent use.

Pink Stork's our stress support formula for women includes 300 mg of organic ashwagandha root per serving, the dose range used across the research. The full formula combines this with algae-sourced DHA, chamomile, saffron, and active-form B vitamins (B6 as Pyridoxal-5-Phosphate and B12 as Methylcobalamin) to support a healthy stress response and a calm, balanced mood.†

What ashwagandha is not

Ashwagandha is not a sedative, and it is not a medication for anxiety disorders. It is an adaptogen that supports the body's resilience to stress when taken consistently over time. It does not produce the immediate effect you might feel from caffeine. Most studies show meaningful effects at the six to twelve week mark, which is why consistency matters more than dose escalation.

Ashwagandha is also not appropriate for everyone. The NCCIH notes that evidence is unclear about its effects on anxiety disorders specifically, and it is not recommended during pregnancy. Always consult your healthcare provider before adding ashwagandha to your routine, particularly if you are pregnant, breastfeeding, or managing a thyroid condition.

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— Amy Suzanne Upchurch, Founder and CEO of Pink Stork

Related guides

• What Are the Signs of High Cortisol in Women?
• Why Does Stress Hit Women Harder Than Men?
• Which B Vitamins Are Depleted by Chronic Stress?

Pink Stork Cortisol Complex is cGMP-certified, ISO 17025 third-party tested, and available at Target, Walmart, and CVS, with 50,000+ verified Amazon reviews across the brand.

Frequently asked questions

Does ashwagandha actually work for stress?

The research base is more substantial than most adaptogens. Multiple meta-analyses of randomized controlled trials have found that standardized ashwagandha supplementation is associated with meaningful reductions in perceived stress and anxiety compared with placebo in adults with chronic stress. Effects are most consistent after eight or more weeks of daily use.

What is KSM-66 ashwagandha?

KSM-66 is a standardized root-only extract of ashwagandha. It is produced exclusively from the root of the plant and is one of the most studied ashwagandha forms in clinical research. Most of the trials showing stress and sleep benefits have used KSM-66 or equivalent root-standardized extracts.

How long does ashwagandha take to work for stress?

Most clinical studies show meaningful effects at the six to twelve week mark with consistent daily use. Ashwagandha is not a fast-acting compound. It supports the body's adaptive response to stress over time rather than producing an immediate effect.

What dose of ashwagandha is supported by research?

The research uses a range of 250 to 600 mg of standardized root extract daily, with 300 mg appearing in multiple positive RCTs. The NIH Office of Dietary Supplements notes that benefits in sleep research were more pronounced at 600 mg and with treatment duration of at least eight weeks.

Is ashwagandha safe during pregnancy?

Ashwagandha is not recommended during pregnancy. Always consult your healthcare provider before taking ashwagandha or any adaptogen if you are pregnant, breastfeeding, trying to conceive, or managing a medical condition.

Can ashwagandha be taken with other supplements?

Ashwagandha is generally well tolerated alongside other supplements, but individual circumstances vary. Consult your healthcare provider if you are taking thyroid medications, immunosuppressants, or sedatives, as interactions are possible.

† These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Always consult your healthcare provider before starting any new supplement, especially during pregnancy, breastfeeding, or while managing a medical condition. Keep out of reach of children.