Withania somnifera, known commonly as ashwagandha,[2][3][4] is an evergreen shrub in the Solanaceae family that is native to the Middle East and North Africa, other African regions, southern Europe, and Indian subcontinent.[2] Several other species in the genus Withania are morphologically similar.[3] Common names include Indian ginseng and winter cherry.[3][5]
W. somnifera is a short shrub 35–75 cm (14–30 in) tall with tomentose branches, dull green elliptic leaves up to 10–12 cm (3.9–4.7 in) long, small green bell-shaped flowers, and orange-red ripe fruit. The Latin species name somnifera means "sleep-inducing," while the name ashwagandha combines the Sanskrit words for "horse" and "smell," referring to the root's strong horse-like odor. It is cultivated mainly in dry regions of India and nearby countries like Nepal, Sri Lanka, China, and Yemen, preferring dry, stony soil with sun to partial shade, and is propagated from seeds in early spring or greenwood cuttings later. It is affected by various pests and diseases in India, which can damage plant health and reduce its secondary metabolite content.
The plant, particularly its root powder, has been used for centuries in traditional Indian medicine.[6] W. somnifera is commonly sold as a dietary supplement containing root or leaf powder or extracts.[3][7] It is undergoing research for potential effects on stress, anxiety, and sleep, but current clinical evidence is insufficient to confirm its safety or efficacy.[3][7][8][9] The primary phytochemicals in W. somnifera are withanolides—structurally similar to ginsenosides in Panax ginseng—along with alkaloids and sitoindosides, leading to its nickname, Indian ginseng.
W. somnifera is generally well tolerated for up to about three months with mostly mild side effects.[7] It should be avoided during pregnancy or in people with hormone-sensitive conditions.[3][7][8] It has been linked to rare cases of liver injury, particularly in people with preexisting liver conditions.[8][10]