Ashwagandha to lower cortisol: what does science say?

Achiel Schoemans
2026-02-27T16:59:49+01:00

Ashwagandha is the most researched adaptogen for cortisol regulation in chronic stress. Discover how KSM-66 works, what withanolides do, and when you can expect to see results.

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An elevated cortisol level can lead to various complaints, such as: poor sleep, becoming easily irritated, and a feeling of being rushed. Ashwagandha is the most researched adaptogen for precisely this problem. But how does it work, what can you expect, and when does it take effect?

What is ashwagandha and why is it called an adaptogen?

Ashwagandha (Withania somnifera) is a plant that has been used in Ayurvedic medicine for over a thousand years. Its active compounds, called withanolides, are primarily found in the plant's root.

Ashwagandha falls under the category of adaptogens, a group of plants that help the body adapt better to stress. Adaptogens do not act as a sedative that makes you drowsy; they help balance your cortisol levels. You can read more about how adaptogens generally work and which other plants fall into this category in our article on [adaptogens to lower cortisol].

How does ashwagandha lower cortisol?

Ashwagandha works via the HPA axis, the system that regulates your stress response. This axis runs from the hypothalamus to the pituitary gland and the adrenal glands. In chronic stress, this system is continuously active, leading to constant cortisol production.

The withanolides in ashwagandha inhibit the excessive activity of the HPA axis. They influence the release of ACTH, the hormone that stimulates the adrenal glands to produce cortisol. By dampening this signal, cortisol production gradually decreases. At the same time, ashwagandha affects the activity of neurotransmitters such as GABA and serotonin, which enhances its calming effect.

A systematic review from 2023 of nine studies concluded that ashwagandha supplementation for 30 to 112 days reduced cortisol excretion by 11 to 32 percent compared to placebo. This is a significant effect for a herbal supplement.

Those who want to read more about which supplements are suitable for cortisol regulation can find an overview in our article on lowering cortisol with supplements.

What makes KSM-66 different from regular ashwagandha?

Not all ashwagandha extracts work the same way. The quality of the extract, its standardization, and the concentration of withanolides largely determine whether you notice an effect. KSM-66 is the most researched ashwagandha extract in the world. It is extracted exclusively from the root, without the use of leaves, and is standardized to a minimum of 5 percent withanolides.

Withanolides are the active compounds in ashwagandha that make the difference. They inhibit the overactivity of the HPA axis, help normalize cortisol production, and support neurotransmitters like GABA that calm your nervous system. Simply put: the more withanolides in an extract, the stronger the effect. Cheap ashwagandha products without standardized withanolides often contain too little of these compounds to make a measurable difference.

Metis Anti-Stress 03 contains 300 mg KSM-66 per two capsules, supplemented with lemon balm, holy basil, and magnesium citrate. A formula for those who want to combine ashwagandha with other stress-supporting ingredients.

How quickly does ashwagandha work for stress?

Ashwagandha does not work acutely. It is not a remedy that you take on an empty stomach and feel the effects an hour later. Most studies show significant effects after four to eight weeks of consistent daily use. Some people notice a difference in how they handle daily stress triggers after just two weeks, while others need more time.

This is due to how adaptogens work: they gradually support your stress system, rather than acutely suppressing it. This makes them particularly suitable for those who are under long-term pressure and want to structurally improve their stress response.

Is ashwagandha safe for daily use?

Multiple randomized, controlled studies show that ashwagandha is well-tolerated with daily use for up to eight weeks, without significant side effects. It is not an addictive substance and does not cause habituation.

Those who are on medication, pregnant, or breastfeeding should consult a doctor before use. Ashwagandha can affect blood sugar levels and interact with certain medications. If in doubt, always discuss its use with your treating physician or pharmacist.

Conclusion

Would you like to know which other methods lower cortisol besides ashwagandha? Then read our overview of 7 proven ways to lower cortisol.

Ashwagandha is the most researched adaptogen for cortisol regulation in chronic stress. The active compounds, withanolides, inhibit the HPA axis and gradually dampen excessive cortisol production. Effects are noticeable after four to eight weeks of consistent use. For those who want a standardized ashwagandha extract in combination with other stress-supporting ingredients, Metis Anti-Stress 03 offers a complete formula.