This is a general overview. For more in-depth information, see our health professional fact sheet.
What is ashwagandha and what does it do?
Ashwagandha is a plant used in traditional Ayurvedic and Unani medicine. It is commonly promoted for sleep, stress, and anxiety as well as cognitive function. Ashwagandha is also known as Withania somnifera, Indian ginseng, and winter cherry.
Ashwagandha supplements usually contain extracts made from the plant’s roots or from the roots and leaves.
Does ashwagandha work?
The health effects of ashwagandha extracts have not been thoroughly studied, but here’s what we have learned from the research so far.
Stress and anxiety
Ashwagandha extracts might help reduce stress and anxiety. In several studies, people who took ashwagandha for 6 to 8 weeks reported that they felt less stress and anxiety as well as less fatigue and sleeplessness. Ashwagandha also lowered stress hormone levels. In some studies, ashwagandha appeared to be more effective when taken at doses of 500 to 600 milligrams (mg) per day compared with lower doses.
Sleep
Results from a few small studies suggest that ashwagandha extracts might improve sleep. In these studies, people who had trouble sleeping and took ashwagandha reported that they fell asleep faster, slept longer, and woke up less often during the night. Overall, the benefits for sleep were small, but ashwagandha seemed most helpful when taken at doses of 600 mg per day or more for at least 8 weeks.
Is ashwagandha safe?
In the studies described above, there were no safety concerns when people used ashwagandha extracts for up to about 3 months. Common side effects of ashwagandha are usually mild and include upset stomach, loose stools, nausea, and feeling drowsy. However, it’s not clear whether ashwagandha is safe to use for longer periods of time.
Ashwagandha extracts have been linked to liver injury in some people, but more research is needed to understand this potential concern.
A few studies show that ashwagandha may affect how your thyroid gland works. Therefore, ashwagandha might interact with thyroid medications. Ashwagandha might also interact with diabetes and blood pressure medications, sedatives, and medications that suppress your immune system.
Ashwagandha may not be safe for people with prostate cancer or those who are pregnant or breastfeeding.
Summary
Several studies have shown that ashwagandha might reduce stress and anxiety. It might also improve how well and how long you sleep. However, more research is needed to confirm these findings. It’s also important to note that studies have used many different types and doses of ashwagandha extracts and most were conducted as part of traditional Ayurvedic or Unani medicine.
Ashwagandha appears to be safe for up to 3 months of use, but it’s not clear if ashwagandha is safe to use for longer periods of time. Ashwagandha might cause liver problems and affect how your thyroid gland works. In addition, it might not be safe for people with prostate cancer or those who are pregnant or breastfeeding.
Disclaimer
This fact sheet by the National Institutes of Health (NIH) Office of Dietary Supplements (ODS) provides information that should not take the place of medical advice. We encourage you to talk to your health care providers (doctor, registered dietitian, pharmacist, etc.) about your interest in, questions about, or use of dietary supplements and what may be best for your overall health. Any mention in this publication of a specific product or service, or recommendation from an organization or professional society, does not represent an endorsement by ODS of that product, service, or expert advice.
Updated:
December 4, 2023