Ashwagandha

Ashwagandha, also known as Withania somnifera, is said to enhance muscle strength, reduce stress, and improve sleep. There has also been interest in ashwagandha use for osteoarthritis.

The evidence supporting the benefits of ashwagandha for improving stress, sleep quality, or other conditions has been limited, in part, by the variability in the ashwagandha extracts being studied (1). However, a meta-analysis of 12 randomized trials comparing specific doses of ashwagandha to placebo in 1002 adults reported a statistically significant reduction in anxiety and stress (2). Some clinical practice guidelines have stated that daily ashwagandha root extract has been used as adjunctive treatment in patients with generalized anxiety disorder (3).

It has been proposed that ashwagandha extracts decrease stress and anxiety by decreasing cortisol levels (4) and increasing serotonin levels (5).

There are also data from randomized trials supporting possibly a mild benefit of ashwagandha for sleep. A meta-analysis of randomized trials comparing ashwagandha extract in capsule form with placebo demonstrated small improvements in sleep quantity and quality, particularly in adults treated > 8 weeks (6). Although no serious adverse effects were reported, longer term safety data are needed.

Adverse effects of ashwagandha may include diarrhea, headache, sedation, or nausea. Liver injury may occur (7). Ashwagandha may increase testosterone levels, which may adversely affect hormone-dependent prostate cancer (8).

Ashwagandha should not be used during pregnancy, due to possible abortifacient effects, or breastfeeding, due to lack of safety data.

Ashwagandha can interact with thyroid hormones and antihyperglycemic, antihypertensive, immunosuppressant, and sedative medications. (See table Some Possible Dietary Supplement–Medication Interactions.)

1. 1. Speers AB, Cabey KA, Soumyanath A, Wright KM. Effects of Withania somnifera (ashwagandha) on stress and the stress-related neuropsychiatric disorders anxiety, depression, and insomnia. Curr Neuropharmacol. 19(9):1468-1495, 2021. doi: 10.2174/1570159X19666210712151556

2. 2. Akhgarjand C, Asoudeh F, Bagheri A, et al. Does Ashwagandha supplementation have a beneficial effect on the management of anxiety and stress? A systematic review and meta-analysis of randomized controlled trials. Phytother Res. 2022;36(11):4115-4124. doi:10.1002/ptr.7598

3. 3. Sarris J, Ravindran A, Yatham LN, et al. Clinician guidelines for the treatment of psychiatric disorders with nutraceuticals and phytoceuticals: The World Federation of Societies of Biological Psychiatry (WFSBP) and Canadian Network for Mood and Anxiety Treatments (CANMAT) Taskforce. World J Biol Psychiatry. 2022;23(6):424-455. doi:10.1080/15622975.2021.2013041

4. 4. Majeed M, Nagabhushanam K, Mundkur L. A standardized Ashwagandha root extract alleviates stress, anxiety, and improves quality of life in healthy adults by modulating stress hormones: Results from a randomized, double-blind, placebo-controlled study. Medicine (Baltimore). 2023;102(41):e35521. doi:10.1097/MD.0000000000035521

5. 5. Majeed M, Nagabhushanam K, Murali A, Vishwanathan DT, Mamidala RV, Mundkur L. A Standardized Withania somnifera (Linn.) Root Extract with Piperine Alleviates the Symptoms of Anxiety and Depression by Increasing Serotonin Levels: A Double-Blind, Randomized, Placebo-Controlled Study. J Integr Complement Med. 2024;30(5):459-468. doi:10.1089/jicm.2023.0279

6. 6. 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;16(9):e0257843. Published 2021 Sep 24. doi:10.1371/journal.pone.0257843

8. 7. Björnsson HK, Björnsson ES, Avula B, et al. Ashwagandha-induced liver injury: A case series from Iceland and the US Drug-Induced Liver Injury Network. Liver Int. 2020;40(4):825-829. doi:10.1111/liv.14393

9. 8. Lopresti AL, Drummond PD, Smith SJ. A randomized, double-blind, placebo-controlled, crossover study examining the hormonal and vitality effects of ashwagandha (Withania somnifera) in aging, overweight males. Am J Mens Health. 13(2):1557988319835985, 2019. doi:10.1177/1557988319835985

The following English-language resource may be useful. Please note that The Manual is not responsible for the content of this resource.

1. National Institutes of Health (NIH), National Center for Complementary and Integrative Health: Ashwagandha