The Truth about Ashwagandha and Cancer: Answers from an MSK Expert

Learn about ashwagandha, an herb used for stress relief.

Ashwagandha may reduce stress, anxiety, and insomnia.

Ashwagandha (Withania somnifera) is an herb that has been used in Ayurveda, the traditional Indian medical system, for more than 3,000 years. It is an adaptogen, which means it is believed to strengthen the body against physical or biological stress. Ashwagandha is used to relieve anxiety, reduce fatigue, and improve general health. So should people with cancer take it? We asked Memorial Sloan Kettering Cancer Center Integrative Medicine Service Pharmacist Jason Hou to explain the science behind it.

Why might ashwagandha be beneficial to cancer patients?

Many cancer patients experience stress related to the diagnosis, treatment, and symptoms associated with cancer and its treatment. The fear of disease recurrence can also be a stressor. Because many patients seek non-pharmaceutical options for stress relief, ashwagandha has become popular in recent years.

Can it prevent or treat cancer? Does it reduce inflammation?

Studies done in the laboratory and in animals have shown that ashwagandha reduces inflammation. But there are no data that support its use to prevent or to treat cancer.

Does MSK prescribe ashwagandha?

Yes, we prescribe this herb at our MSK herbal dispensary.

Who should take it?

Although ashwagandha is not officially listed as “generally recognized as safe” by the U.S. Food and Drug Administration, several studies have examined its use in people with stress, anxiety, low stamina, infertility, and even cancer. Data show that it is safe in healthy adults. People with underlying disease or medical conditions should talk to their healthcare providers before taking it.

How do you take it?

Ashwagandha is taken orally in the form of capsules, tablets, gummies, and liquid extracts. It can also be used topically in the form of cream for pain relief.

Is it safer than a prescription stress reliever or an antidepressant?

Ashwagandha has not been compared to prescription medications for depression or anxiety. But available data suggest that in patients who have generalized anxiety disorder, it works well when combined with one type of these medications, called selective serotonin reuptake inhibitors (SSRIs). However, ashwagandha can cause adverse effects and interact with other medications that you may be taking, so talk to your healthcare providers before taking it.

What are the side effects?

Common side effects include mild to moderate drowsiness that comes and goes, stomachaches, and diarrhea.

Should people stop taking it before surgery?

Ashwagandha has a sedative effect, which means it can make you sleepy. Because sedatives are used before and during surgery, it is advisable to stop taking this herb one week before surgery.

Can people use it to protect against or treat COVID-19?

No, there is no proof that ashwagandha can protect against or treat COVID-19.

What impact does it have on testosterone levels? Should women avoid it?

In a small study of overweight men with mild fatigue, ashwagandha was found to increase testosterone levels. However, these findings cannot be generalized to the wider population. Safety studies have yet to be conducted in women. Until such data become available, pregnant or breastfeeding women should avoid this herb.

Why is ashwagandha not advisable for people with autoimmune disorders?

In people with autoimmune disorders, the immune system is already overactive. Because ashwagandha can stimulate the immune system, it can rev up your immune system even more, and that can be harmful.

What do we still need to learn about ashwagandha?

Even though this herb is used for relieving stress, anxiety, and insomnia, strong clinical data are lacking. We need well-designed, large studies for determining the true therapeutic value of ashwagandha.

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