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Does ashwagandha really work against stress?

Moderate evidence

Ashwagandha demonstrably lowers the stress hormone cortisol, but whether it actually makes you feel better has not yet been convincingly proven. Short-term use (up to around 12 weeks) appears to be safe, but too little is known about long-term use to be certain.

Ashwagandha measurably and consistently lowers cortisol in the blood. A meta-analysis of seven smaller RCTs (together involving nearly 500 participants) found a clear reduction in cortisol levels. That is biologically interesting: cortisol is the primary stress hormone, produced by what is known as the stress axis in your body.

Whether you actually feel less stressed is a different matter. That same meta-analysis found no statistically significant effect on the Perceived Stress Scale, a standard questionnaire that measures how burdensome people find their lives. The biological measurement and the subjective experience therefore diverge. That is an honest and important distinction.

Individual studies paint a more nuanced picture. Two RCTs using 240 mg/day (60 participants) and 125 mg/day (98 participants) respectively did find significant reductions in stress and anxiety compared with placebo. One study using 400 mg/day in people with overweight, however, found no effect on perceived stress, although there was less fatigue. In short: the results are not consistent across all populations and doses.

Two caveats deserve extra attention. In one positive study (500 mg/day, n=50), the researchers were employed by the manufacturer, which makes the findings less independent. In addition, a systematic review explicitly warns that no one has investigated what long-term use does to adrenal function. In the short term (8 to 12 weeks), ashwagandha appears to be well tolerated without side effects, but beyond that it is uncharted territory. Do you have a thyroid condition or other hormone-related complaints? Then discuss it with your doctor first.

The evidence
7 studies · 2 meta-analyses · ≈ 1,000 participants

Based on 1 meta-analysis (7 RCTs, n≈488), 1 systematic review (9 clinical studies), and 4 individual RCTs (n=50-98). All studies are short-term (8-16 weeks). Conflicts of interest in two manufacturer-sponsored RCTs.

Last checked: August 2026 · how this was judged
Related answers

How much ashwagandha do you need per day?

For stress reduction, 240 to 500 mg per day already appears to have an effect; for safety, 600 mg per day has been studied for up to 8 weeks. The studies involved are relatively small, so consult your doctor if you are unsure or are taking medication.

Yes · Moderate evidence

Is it better to take ashwagandha in the morning or in the evening?

More important than the timing: several regulators advise against ashwagandha. The Dutch RIVM warns against it (liver, thyroid, hormones, pregnancy) and Denmark has banned it in supplements. If you use it anyway, the timing makes no difference: morning versus evening has never been directly compared, so pick the moment you can keep up.

Insufficient evidence

Does shilajit actually work as a supplement?

Be careful. There is little strong evidence that shilajit works, it has no authorised novel-food status in the EU, and unregulated products can contain heavy metals such as lead, arsenic and mercury.

Preliminary evidence

Does echinacea really work against the common cold?

Echinacea has not been proven effective against the common cold. If you still want to try something, Echinacea purpurea (above-ground parts) has the most, though still mixed, indications for early use at the onset of a cold.

No · Moderate evidence

How healthy is meditation, and what does it actually do for you?

Meditation has a moderate but well-demonstrated effect on depression, anxiety and pain, and can safely be combined with other treatments. For other health claims the evidence is still too thin to rely on.

Yes · Strong evidence

Do functional mushrooms like reishi and cordyceps actually work?

Medicinal mushrooms such as reishi show promising effects in the laboratory, but convincing evidence in humans is still lacking. Also check the species: cordyceps of the species Cordyceps militaris (the form most supplements use) is not authorised in the EU and may not be sold — the Dutch NVWA removed these products from the market in 2025. If you use medications, always consult your doctor first.

Preliminary evidence
All Ashwagandha answers on “What works”
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