Ashwagandha: What the Research Shows

Ashwagandha is the most-studied adaptogen, with randomized trials reporting reduced stress and improved sleep. Here’s the evidence, the doses used, and the caveats.

By PGP Iyer · May 28, 2026 · 1 min read

Ashwagandha (Withania somnifera) is an Ayurvedic herb classed as an “adaptogen” — a plant said to help the body cope with stress. It is the most-studied adaptogen, and the trial evidence is moderate and encouraging.

Stress and anxiety

A systematic review and meta-analysis concluded that ashwagandha supplementation reduced stress and anxiety versus placebo. An earlier randomized, double-blind, placebo-controlled trial reported lower perceived stress and serum cortisol with a standardized root extract.

Sleep

A randomized, placebo-controlled trial found ashwagandha root extract improved sleep parameters and anxiety. Effects build over weeks of daily use.

The caveats

Trials use standardized root extracts at specific doses, so results don’t automatically transfer to any product. Ashwagandha is generally well tolerated short-term, but it isn’t recommended in pregnancy and can interact with thyroid, sedative, or immune medications — check with a clinician if that’s you.