Withania somnifera - Ashwagandha

The plant, particularly its root powder, has been used for centuries in traditional Indian medicine.

 W. somnifera is commonly sold as a dietary supplement, containing root or leaf powder or extracts. It is undergoing research for potential effects on stress, anxiety, and sleep, but current clinical evidence is insufficient to confirm its safety or efficacy.

Stress and anxiety

At oral doses of 300 to 600 mg per day over a three month period, ashwagandha root extract may be useful in treating generalized anxiety disorder, although the evidence for efficacy is tentative and the treatment may cause nausea and diarrhea.

Sleep

There is limited evidence that W. somnifera extract, especially at higher doses and over longer durations, may modestly improve sleep quality and related outcomes, with more noticeable effects in people with insomnia. A 2021 review concluded that W. somnifera extract modestly improves sleep quality and quantity in adults, especially those with insomnia, and may reduce anxiety and enhance alertness.

Phytochemistry

The main phytochemical constituents ofW. somnifera are withanolides, a group of triterpene lactones that include withaferin A, alkaloids, steroidal lactones,tropine, and cuscohygrine. Forty withanolides, twelve alkaloids, and various sitoindosides have been isolated from this plant species.

As these withanolides are structurally similar to the ginsenosides of Panax ginseng,W. somniferais commonly referred to as "Indian ginseng".