Here are 12 benefits of ashwagandha that are supported by science.

Ashwagandha is one of the most important herbs in Ayurveda, a form of alternative medicine based on Indian principles of natural healing.

It has been used for over 3,000 years to relieve stress, increase energy levels, and improve concentration (1Trusted Source).

Ashwagandha is Sanskrit for smell of the horse, which refers to both its unique smell and ability to increase strength.

Its botanical name is Withania somnifera, and it’s also known by several other names, including Indian ginseng and winter cherry.

The ashwagandha plant is a small shrub with yellow flowers that’s native to India and North Africa. Extracts or powder from the plant’s root or leaves are used to treat a variety of conditions.

Many of its health benefits are attributed to its high concentration of withanolides, which have been shown to fight inflammation and tumor growth (1Trusted Source).

In several studies, ashwagandha has been shown to lower blood sugar levels.

One test-tube study found that it increased insulin secretion and improved insulin sensitivity in muscle cells (2Trusted Source).

Also, several human studies have suggested that it can reduce blood sugar levels in both healthy people and those with diabetes (3, 4Trusted Source, 5Trusted Source, 6Trusted Source).

Additionally, in a 4-week study in people with schizophrenia, those treated with ashwagandha had an average reduction in fasting blood sugar levels of 13.5 mg/dL, compared with 4.5 mg/dL in those who received a placebo (5Trusted Source).

What’s more, in a small study in 6 people with type 2 diabetes, supplementing with ashwagandha for 30 days lowered fasting blood sugar levels. However, the study didn’t include a control group, making the results questionable (6Trusted Source).

Animal and test-tube studies have found that withaferin — a compound in ashwagandha — helps induce apoptosis, which is the programmed death of cancer cells (7Trusted Source).

It also impedes the growth of new cancer cells in several ways (7Trusted Source).

First, withaferin is believed to promote the formation of reactive oxygen species (ROS) inside cancer cells, disrupting their function. Second, it may cause cancer cells to become less resistant to apoptosis (8Trusted Source).

Animal studies suggest that it may help treat several types of cancer, including breast, lung, colon, brain, and ovarian cancer (9Trusted Source, 10Trusted Source, 11Trusted Source, 12Trusted Source, 13Trusted Source).

In one study, mice with ovarian tumors treated with withaferin alone or in combination with an anti-cancer drug showed a 70–80% reduction in tumor growth. The treatment also prevented the spread of cancer to other organs (13Trusted Source).

Although no evidence suggests that ashwagandha exerts similar effects in humans, the current research is encouraging.

Cortisol is known as a stress hormone given that your adrenal glands release it in response to stress, as well as when your blood sugar levels get too low.

Unfortunately, in some cases, cortisol levels may become chronically elevated, which can lead to high blood sugar levels and increased fat storage in the abdomen.

Studies have shown that ashwagandha may help reduce cortisol levels (3, 14Trusted Source, 15Trusted Source).

In one study in chronically stressed adults, those who supplemented with ashwagandha had significantly greater reductions in cortisol, compared with the control group. Those taking the highest dose experienced a 30% reduction, on average (3).

Ashwagandha is perhaps best known for its ability to reduce stress.

Researchers have reported that it blocked the stress pathway in the brains of rats by regulating chemical signaling in the nervous system (16Trusted Source).

Also, several controlled human studies have shown that it can reduce symptoms in people with stress and anxiety disorders (14Trusted Source, 17Trusted Source, 18Trusted Source).

In a 60-day study in 64 people with chronic stress, those in the group that supplemented with ashwagandha reported a 69% reduction in anxiety and insomnia, on average, compared with 11% in the placebo group (14Trusted Source).

In another 6-week study, 88% of people who took ashwagandha reported a reduction in anxiety, compared with 50% of those who took a placebo (18Trusted Source).

Although it hasn’t been thoroughly studied, a few studies suggest ashwagandha may help alleviate depression (14Trusted Source, 18Trusted Source).

In one controlled 60-day study in 64 stressed adults, those who took 600 mg of high-concentration ashwagandha extract per day reported a 79% reduction in severe depression, while the placebo group reported a 10% increase (14Trusted Source).

However, only one of the participants in this study had a history of depression. For this reason, the relevance of the results is unclear.

Ashwagandha supplements may have powerful effects on testosterone levels and reproductive health (15Trusted Source, 19Trusted Source, 20Trusted Source, 21Trusted Source).

In one study in 75 infertile men, the group treated with ashwagandha showed increased sperm count and motility.

What’s more, the treatment led to a significant increase in testosterone levels (21Trusted Source).

The researchers also reported that the group who took the herb had increased antioxidant levels in their blood.

In another study, men who received ashwagandha for stress experienced higher antioxidant levels and better sperm quality. After 3 months of treatment, 14% of the men’s partners had become pregnant (15Trusted Source).

Research has shown that ashwagandha may improve body composition and increase strength (4Trusted Source, 20Trusted Source, 22Trusted Source).

In a study to determine a safe and effective dosage for ashwagandha, healthy men who took 750–1,250 mg of pulverized ashwagandha root per day gained muscle strength after 30 days (4Trusted Source).

In another study, those who took ashwagandha had significantly greater gains in muscle strength and size. It also more than doubled their reductions in body fat percentage, compared with the placebo group (20Trusted Source).

Several animal studies have shown that ashwagandha helps decrease inflammation (23Trusted Source, 24Trusted Source, 25Trusted Source).

Studies in humans have found that it increases the activity of natural killer cells, which are immune cells that fight infection and help you stay healthy (26Trusted Source, 27Trusted Source).

It has also been shown to decrease markers of inflammation, such as C-reactive protein (CRP). This marker is linked to an increased risk of heart disease.

In one controlled study, the group who took 250 mg of standardized ashwagandha extract daily had a 36% decrease in CRP, on average, compared with a 6% decrease in the placebo group (3).

In addition to its anti-inflammatory effects, ashwagandha may help improve heart health by reducing cholesterol and triglyceride levels.

Animal studies have found that it significantly decreases levels of these blood fats.

One study in rats found that it lowered total cholesterol and triglyceride levels by 53% and nearly 45%, respectively (28Trusted Source).

While controlled human studies have reported less dramatic results, they have observed some impressive improvements in these markers (3, 4Trusted Source, 5Trusted Source, 6Trusted Source).

In a 60-day study in chronically stressed adults, the group taking the highest dosage of standardized ashwagandha extract experienced a 17% decrease in LDL (bad) cholesterol and an 11% decrease in triglycerides, on average (3).

Test-tube and animal studies suggest that ashwagandha may mitigate memory and brain function problems caused by injury or disease (29Trusted Source, 30Trusted Source, 31Trusted Source, 32Trusted Source).

Research has shown that it promotes antioxidant activity that protects nerve cells from harmful free radicals.

In one study, rats with epilepsy that were treated with ashwagandha had nearly a complete reversal of spatial memory impairment. This was likely caused by a reduction in oxidative stress (32Trusted Source).

Although ashwagandha has traditionally been used to boost memory in Ayurvedic medicine, only a small amount of human research has been conducted in this area.

In one controlled study, healthy men who took 500 mg of standardized extract daily reported significant improvements in their reaction time and task performance, compared with men who received a placebo (33Trusted Source).

Another 8-week study in 50 adults showed that taking 300 mg of ashwagandha root extract twice daily significantly improved general memory, task performance, and attention (34Trusted Source).

Ashwagandha is a safe supplement for most people, although its long-term effects are unknown.

However, certain individuals should not take it, including pregnant and breastfeeding women.

People with autoimmune diseases should also avoid ashwagandha unless authorized by a healthcare provider. This includes people with conditions like rheumatoid arthritis, lupus, Hashimoto’s thyroiditis, and type 1 diabetes.

Additionally, those on medication for thyroid disease should be careful when taking ashwagandha, as it may increase thyroid hormone levels in some people.

It may also decrease blood sugar and blood pressure levels, so medication dosages may need to be adjusted if you take it.

The recommended dosage of ashwagandha depends on the type of supplement. Extracts are more effective than crude ashwagandha root or leaf powder. Remember to follow instructions on labels.

Standardized root extract is commonly taken in 450–500-mg capsules once or twice daily.

Ashwagandha is an ancient medicinal herb with multiple health benefits.

It can reduce anxiety and stress, help fight depression, boost fertility and testosterone in men, and even boost brain function.

Supplementing with ashwagandha may be an easy and effective way to improve your health and quality of life.