Ashwagandha: what the evidence shows, and what it does not

Ashwagandha (Withania somnifera) is a root sold as a food supplement. No health claim for it is authorised in the EU, and the human evidence is limited and inconsistent. Trials typically use 300 to 600 mg daily of a standardised extract for eight to twelve weeks. It is not a treatment for anxiety disorders, depression or insomnia, and it carries real interaction and liver risks.

Key points

• No EU health claim is authorised for ashwagandha, and the human evidence is limited and inconsistent.
• Doses studied are 300 to 600 mg daily of a standardised root extract over eight to twelve weeks.
• Withanolide content varies between products, so a milligram figure alone says little.
• Rare liver injury has been reported; jaundice, dark urine or persistent nausea means stop and seek advice.
• It should be avoided in pregnancy and breastfeeding, and cleared medically in thyroid, autoimmune and hormone-sensitive disease.

A supplement can be described without anything being claimed for it.

Ashwagandha, scientifically known as Withania somnifera, is a root used in Ayurvedic tradition and sold in Europe as a food supplement. No health claim for it is authorised in the EU. It is often described casually as an “adaptogen.” Clinically, that word should not replace precision.

The available human evidence summarised by the NIH National Center for Complementary and Integrative Health notes that the human research is limited and inconsistent, and that the evidence is insufficient for the outcomes commonly associated with the supplement, including stress, sleep, anxiety, cognition, athletic performance, diabetes and menopause.

That distinction is important. In longevity medicine, a supplement should have a defined purpose, a defined period of use, and a scheduled review of tolerance and safety.

Who asks about ashwagandha?

The question usually comes from adults carrying a high stress load or sleeping poorly. Where it is discussed, it is discussed as an unproven option alongside a proper assessment of the underlying cause.

It is not a treatment for depression, anxiety disorders, burnout, insomnia, thyroid disease or chronic fatigue. These conditions require a proper medical evaluation rather than self-treatment with supplements.

What doses have been studied, and for how long?

The randomised trials indexed on PubMed most commonly use standardised root extracts rather than unstandardised powder. The doses studied in that literature are:

• 300 mg daily of a standardised root extract
• Up to 300 mg twice daily in some trials
• Study periods of roughly 8–12 weeks rather than indefinite use

The concentration of active compounds, known as withanolides, varies significantly between products. A dose expressed only in milligrams is therefore incomplete without knowing the extract standardisation and source.

Where a patient chooses to use it, the lowest studied dose, documented tolerance monitoring and a fixed stop date are the minimum conditions.

Is ashwagandha safe, and what are the side effects?

Ashwagandha may cause drowsiness, stomach upset, diarrhoea or vomiting. Rare cases of liver injury are documented in LiverTox (NIH).

It should generally be avoided during pregnancy and breastfeeding. It is also not appropriate without medical approval for people with thyroid disorders, autoimmune disease, hormone-sensitive prostate cancer, imminent surgery, or those taking sedatives, anti-seizure medicines, diabetes medication, blood-pressure medication, immunosuppressants or thyroid hormone.

Always discuss ashwagandha with your physician before use. Stop it and seek medical advice promptly if you develop jaundice, dark urine, unusual itching, persistent nausea or upper abdominal pain.

Where does it sit in a longevity protocol?

Behind everything with a stronger evidence base. Ashwagandha is not a substitute for the interventions with the strongest clinical foundation: regular sleep timing, sufficient protein and micronutrient intake, resistance training, daylight exposure, appropriate caffeine timing and a medical review where symptoms persist.

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Reviewed by Dr. Erietta Galani, MD, PhD in cellular immunology, dual specialty in internal medicine and intensive care, Founder and Medical Lead, minus10med, Athens.
Last reviewed: 11 August 2026

This article is educational and does not replace individual medical advice, diagnosis or treatment.