What is ashwagandha?
Withania somnifera
Ashwagandha is a shrub whose root is used in Ayurveda to help the body handle stress, and in modern trials it modestly reduced stress, cortisol and sleep problems.
Think of ashwagandha as a dimmer switch for the body's alarm system: it may turn the stress response down a notch, not switch it off.
Why it matters for aging
The name comes from Sanskrit and refers to the smell of horse, from the root's strong odor, and to the strength it was believed to give. It's one of the most important herbs in rasayana, Ayurveda's branch of rejuvenation.
Most modern trials use concentrated root extracts at 300 to 600 mg a day for 6 to 12 weeks. Benefits are modest, and safety concerns mean people with liver, thyroid or autoimmune conditions should check with a doctor first.
A common myth
Ashwagandha is a gentle herb that's safe for everyone.
It has real evidence for stress and sleep, but it's been linked to rare liver injury, can raise thyroid hormones, and isn't recommended in pregnancy. Denmark moved to ban it after a disputed risk assessment.
Go deeper
Deep dives
- Ashwagandha: benefits, risks and who should avoid it
- Ayurveda and longevity: what science says about the ancient system
Related terms
Updated Nov 9, 2026 · All terms