Herbs & Remedies
Ashwagandha: Benefits, Dosage, Side Effects and Who Should Avoid It
An honest look at ashwagandha — what small trials suggest, doses studied, side effects, interactions, and who should not take it.
An honest look at ashwagandha — what small trials suggest, doses studied, side effects, interactions, and who should not take it.
Medically reviewed by Dr. Nirmal P Raj & Dr. Chanthni Nirmal, BAMS, MD (Ayurveda) — Santhwana Siddha Clinic, Chalachal Siddha Varma Vidhyashala
Ashwagandha (Withania somnifera) is one of Ayurveda's best-known herbs, traditionally classed as a Rasayana (rejuvenative) and used for stress, weakness and sleep. It is now sold worldwide as a supplement, with marketing claims that often run ahead of the evidence.
This guide summarises what small clinical trials suggest, the doses studied, the side effects and interactions worth knowing, and who should avoid it. It is general information, not medical advice.
Ashwagandha is a shrub whose root is used in Ayurvedic medicine. The name is often translated as relating to the smell of a horse, and the herb is traditionally associated with vitality and resilience. It is often described as an 'adaptogen' — a marketing and research term for substances said to help the body cope with stress — though that category is not a formal medical one.
Several small, short randomised trials have reported that standardised ashwagandha root extract may lower perceived stress and anxiety scores, and improve sleep quality, compared with placebo. Evidence for other claims — testosterone, muscle strength, thyroid, blood sugar — is thinner and mixed. Trials are typically small, short (weeks to a few months) and often use different extracts, so results cannot simply be generalised to any product.
Trials have commonly used roughly 300–600 mg per day of a standardised root extract, taken once or twice daily. This is not a recommendation: the right dose depends on the product, the person and any conditions or medicines. Ayurvedic physicians usually prescribe herbs individually after assessing the person.
In a physician-led program, herbs like ashwagandha are chosen in the context of your dosha, digestion and condition, alongside diet and therapies such as Shirodhara for stress — see Ayurveda for anxiety and stress.
Traditionally for stress, weakness and sleep. Small clinical trials suggest it may modestly reduce stress and anxiety scores and improve sleep, but evidence is limited and short-term.
Studies have commonly used about 300–600 mg per day of a standardised root extract. This is not a recommendation; ask a doctor about a dose suitable for you.
Many people take it for weeks to months without problems, but long-term safety data are limited and rare liver injury has been reported. Check with a doctor, especially if you take other medicines.
It is generally avoided in pregnancy, and people with liver disease, thyroid conditions or autoimmune conditions should talk to a doctor first. Stop before surgery as advised by your surgeon.
It may interact with sedatives, thyroid medicines, diabetes and blood-pressure medicines, and immunosuppressants. Always tell your doctor and pharmacist what supplements you take.