Ashwagandha is an incredibly healthy medicinal herb.

It’s classified as an "adaptogen," meaning that it can help your body manage stress.

Ashwagandha also provides all sorts of other benefits for your body and brain.

For example, it can lower blood sugar levels, reduce cortisol, boost brain function and help fight symptoms of anxiety and depression.

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

Proven Ashwagandha Benefits

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 ().

"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 ().

Summary Ashwagandha is a prominent herb in Indian Ayurvedic medicine and has become a popular supplement due to its health benefits.

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 ().

Also, several human studies have confirmed its ability to reduce blood sugar levels in both healthy people and those with diabetes (, , , ).

Additionally, in one four-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 to 4.5 mg/dL in those who received a placebo ().

What's more, in a small study in six people with type 2 diabetes, supplementing with ashwagandha for 30 days lowered fasting blood sugar levels as effectively as an oral diabetes medication ().

Summary Ashwagandha may reduce blood sugar levels through its effects on insulin secretion and sensitivity.

Animal and test-tube studies have found that ashwagandha helps induce apoptosis, which is the programmed death of cancer cells ().

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

First, ashwagandha is believed to generate reactive oxygen species (ROS), which are toxic to cancer cells but not normal cells. Second, it may cause cancer cells to become less resistant to apoptosis ().

Animal studies suggest that it may help treat several types of cancer, including breast, lung, colon, brain and ovarian cancer (, , , , ).

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

Although there are no studies to confirm these results in humans yet, the research to date is encouraging.

Summary Animal and test-tube studies have shown that ashwagandha promotes the death of tumor cells and may be effective against several types of cancer.

Cortisol is known as a "stress hormone" because 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 (, , ).

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

Summary Ashwagandha supplements may help lower cortisol levels in chronically stressed individuals.

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

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

Several controlled human studies have shown that it can effectively reduce symptoms in people with stress and anxiety disorders as well (, , ).

In a 60-day study in 64 people with chronic stress, those in the supplemental group reported a 69% average reduction in anxiety and insomnia, compared to 11% in the placebo group ().

In another six-week study, 88% of people who took ashwagandha reported a reduction in anxiety, compared to 50% of those who took a placebo ().

Summary Ashwagandha has been shown to reduce stress and anxiety in both animal and human studies.

Although it hasn't been thoroughly studied, a few studies suggest ashwagandha may help alleviate depression (, ).

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

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

Summary The limited research available suggests that ashwagandha may help reduce depression.

Ashwagandha supplements may have powerful effects on testosterone levels and reproductive health (, , , ).

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 ().

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 three months of treatment, 14% of the men's partners had become pregnant ().

Summary Ashwagandha helps increase testosterone levels and significantly boosts sperm quality and fertility in men.

Research has shown that ashwagandha may improve body composition and increase strength (, , ).

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

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

Summary Ashwagandha has been shown to increase muscle mass, reduce body fat and increase strength in men.

Several animal studies have shown that ashwagandha helps decrease inflammation (, , ).

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 (, ).

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 ashwagandha daily had a 36% decrease in CRP, on average, compared to a 6% decrease in the placebo group ().

Summary Ashwagandha has been shown to increase natural killer cell activity and decrease markers of inflammation.

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 these blood fats.

One study in rats found that it lowered total cholesterol by as much as 53% and triglycerides by nearly 45% ().

While controlled human studies have reported less dramatic results, they have observed some impressive improvements in these markers (, , , ).

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

Summary Ashwagandha may help reduce the risk of heart disease by decreasing cholesterol and triglyceride levels.

Test-tube and animal studies suggest that ashwagandha may reduce memory and brain function problems caused by injury or disease (, , , ).

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

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

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

In one controlled study, healthy men who took 500 mg of the herb daily reported significant improvements in their reaction time and task performance, compared to men who received a placebo ().

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

Summary Ashwagandha supplements may improve brain function, memory, reaction times and the ability to perform tasks.

Ashwagandha is a safe supplement for most people.

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

People with autoimmune diseases should also avoid ashwagandha unless authorized by a doctor. 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 potentially 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.

Ashwagandha dosages in studies typically ranged from 125–1,250 mg daily. In studies where different dosages were taken, the higher dosage usually produced the most dramatic improvements.

If you want to supplement with ashwagandha, look for root extract or powder in 450–500 mg capsules and take it once or twice per day.

It’s offered by several supplement manufacturers and available from various retailers, including health food stores and vitamin shops.

There's also a great selection of high-quality supplements available .

Summary Although ashwagandha is safe for most people, certain individuals shouldn't use it unless authorized by their doctor. The recommended dosage is 450–500 mg once or twice per day.

Ashwagandha is a traditional medicinal herb with multiple health benefits.

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

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