This meta-analysis included 5 randomized and controlled trials assessing the effects of ashwagandha on sleep (n = 400 participants). Ashwagandha extract exhibited a small but significant effect on overall sleep. The effects on sleep were more prominent in the subgroup of adults diagnosed with insomnia, treatment with dosage greater than 600 mg/day, and treatment duration of at least 8 weeks. Ashwagandha extract was also found to improve mental alertness on rising and anxiety level. Therefore, ashwagandha seems effective to improve sleep in humans.
Cheah KL, Norhayati MN, Husniati Yaacob L, Abdul Rahman R. Effect of Ashwagandha (Withania somnifera) extract on sleep: A systematic review and meta-analysis. PLoS One. 2021 Sep 24;16(9):e0257843.