Health Benefits of Ashwagandha

Ashwagandha is an herb commonly used in traditional medicine in India that comes from Withania somnifera, a small evergreen shrub native to parts of Asia, Africa, and Europe. It's also known as winter cherry, dunal, solanaceae, or Indian ginseng, even though it's not part of the ginseng family.

Ashwagandha plays a key role in Ayurveda, an ancient Indian healing system that uses a holistic, or whole-body, approach to balance energies within the body. For over 6,000 years, Ayurvedic practitioners have used ashwagandha as a multi-purpose treatment to promote longevity and ease everything from stress to constipation. It is known as a Rasayana: an herb prepared as a tonic that increases energy and promotes youthfulness.

It has also become popular in Western countries, including the United States, because of its potential health benefits. It's widely offered as a topical treatment or dietary supplement that comes in a variety of forms.

Research has yet to determine whether ashwagandha helps all the conditions it's used to manage. However, a growing body of research demonstrates many potential mental and physical benefits such as the following.

Reduces Anxiety

In Ayurvedic medicine, ashwagandha is considered an adaptogen: a natural substance that can support immunity and help the body respond to stress by decreasing cortisol levels. There's some scientific support for this claim.

Researchers reviewed four studies in which people with a history of anxiety took 125 milligrams (mg) to 1,000 mg of ashwagandha extract daily for one to two months. In all four studies, participants who took the herb reported feeling lower levels of anxiety and stress than participants who took a placebo. 

These studies had methodological flaws. Two of them were small (less than 100 participants), and the others had a potential for biased results. In other words, the results might not reflect how ashwagandha affects the general population. Still, together, these studies suggest that ashwagandha may help reduce symptoms of anxiety and stress.

Ashwagandha root and powder in wooden cups on dark background

eskymaks/Getty Images

Boosts Cognitive Abilities

Several randomized double-blind, placebo-controlled studies—considered the gold standard in scientific research—suggest that ashwagandha may improve certain cognitive functions.

In studies like these, one group of people takes the active substance being studied (in this case, ashwagandha). The other group takes a placebo: a sugar pill with no active properties. Neither the researchers nor the participants know who's taking the active substance or the placebo, which helps prevent biased results.

In one study, participants with mild cognitive decline who took 600 mg of ashwagandha extract daily showed improved immediate and general memory compared with participants who took a placebo. Another study found that people with bipolar disorder performed better on memory and social cognition tasks after taking 500 mg of ashwagandha daily for eight weeks.

A third study yielded similar results for people with no cognitive impairments. After taking 400 mg of root and leaf extract daily for 30 days, ashwagandha users appeared to have better memory and attention span than placebo users. The study only involved 13 participants, so larger studies are needed to support the findings.

Enhances Exercise Performance

Researchers reviewed 12 studies that measured ashwagandha's effect on aspects of physical performance, including strength and power, cardiorespiratory fitness, and fatigue and recovery-related variables. Together, these studies showed that taking between 330 mg and 1,250 mg of ashwagandha daily may help:

Several studies suggest that ashwagandha might also boost VO2 max. VO2 max refers to the maximum amount of oxygen used during intense exercise: The more oxygen you can produce, the harder you can exercise without feeling tired. VO2 max is used as a measure of cardiovascular fitness.

These results are promising, but more research is needed.

Increases Sperm Health and Testosterone Levels

Ashwagandha may play a role in reproductive health. In a review of four studies, researchers examined how ingesting ashwagandha for 90 days affects sperm health. They found that the herb resulted in a statistically significant increase in the following:

  • Sperm concentration: The number of sperm per milliliter of semen
  • Semen volume: The total amount of fluid released in one ejaculation
  • Sperm motility: How well the sperm move or swim
  • Luteinizing hormones: Hormones that cause the testicles to make testosterone
  • Testosterone levels: The amount of testosterone, a hormone produced by the testes, in a blood sample

Again, larger, better-designed studies are needed to support these findings.

Improves Sleep Quality

According to several small studies, taking ashwagandha may help people sleep better. In one study, 29 people with insomnia took 300 mg of ashwagandha twice daily. Compared to a group of 19 people who took a placebo, the test group:

  • Fell asleep faster
  • Spent more time asleep while in bed
  • Had better sleep quality 

Another study found that 40 people with anxiety who took 300 mg or 600 mg of ashwagandha daily reported better sleep than participants in the placebo group after four weeks and eight weeks.

Reduces Blood Sugar Levels

A meta-analysis of 24 studies suggests that ashwagandha may play a role in managing diabetes. According to the analysis, ingesting the herb can decrease:

  • Blood sugar: The main sugar, also known as glucose, in your blood, which comes from the food you eat
  • Insulin: A hormone produced by the pancreas that regulates your blood sugar
  • Lipids: Fatty compounds essential to many bodily functions
  • Oxidative stress markers: Signs that your body has an insufficient level of antioxidants to protect it from unstable and harmful free radicals
  • Glycosylated hemoglobin: Your average glucose (blood sugar) levels for the previous two to three months

This provides some evidence that ashwagandha could play a role in managing diabetes, but larger, longer-term studies are needed.

Improves Arthritis Symptoms

One small study showed that ashwagandha may improve symptoms of rheumatoid arthritis. Study participants reported feeling better after ingesting 10 grams (g) of ashwagandha powder daily for three weeks and then 100 mg of another Ayurvedic medicine—Sidh Makardhwaj—every day for four weeks. Sidh Makardhwaj is a mercury-based compound used to help treat rheumatoid arthritis and neurological disorders.

While this is a promising result, more evidence is needed to fully understand how ashwagandha might affect arthritis.

How To Take Ashwagandha

Traditional medicine practitioners use the entire plant to treat conditions, but most commercial products contain either the root or a root-and-leaf combination. These parts (and stems) contain the plant's main active compound, withanolides. Withanolides are natural steroids shown to have healing properties for cancer and neurodegenerative conditions like Alzheimer's disease and Parkinson's disease.

Commercial ashwagandha is available in many forms, including tea, capsules, and topical moisturizing creams. Ashwagandha powder is another common form, which you can mix with sweet liquids to offset the bitter flavor.

There’s no official guidance on the best time of day to take ashwagandha, whether you can consume it on an empty stomach, and how long it might take to see results. However, researchers generally see effects after four to 12 weeks of ingestion.


There are no official dosing guidelines for ashwagandha, but study participants typically take between 300 mg and 1,000 mg daily for up to three months. Higher dosages may be beneficial for athletes undergoing an intense physical fitness regimen.

When using an over-the-counter product, it's important to follow the instructions and look for ashwagandha root extract on the label. A healthcare provider can provide dosing suggestions based on your individual circumstances.

Is Ashwagandha Safe?

Research shows that most people can safely take ashwagandha by mouth for up to three months. There’s no reliable information on the safety of topical treatments or the long-term effects of oral supplements.

Some Ayurvedic medicines may contain lead, mercury, or arsenic in toxic amounts. However, a lab test found no toxic levels of these chemicals in an ashwagandha sample.

Some groups should avoid taking ashwagandha, including:

  • People who are pregnant: Ashwagandha may cause a miscarriage.
  • People who are breastfeeding: There's not enough information to know how the herb affects breastfeeding people or their babies.
  • People who are having surgery: Because ashwagandha may slow the nervous system, anesthesia may increase this effect.
  • People with thyroid disease: The herb could increase thyroid levels.

Ashwagandha might also increase autoimmune disease symptoms. However, in the study on patients with rheumatoid arthritis noted above, participants did not experience worsening symptoms after taking the herb.

Potential Drug Interactions

Ashwagandha may interfere with several types of drugs, including:

  • Antidiabetes medications: Because ashwagandha might lower blood sugar levels, taking it with diabetes medications might cause blood sugar to drop too low. 
  • High blood pressure medications: Ashwagandha might lower blood pressure, potentially causing it to dip too much if paired with antihypertensive (blood pressure lowering) drugs. 
  • Immunosuppressants: Ashwagandha may boost immune system activity, which could decrease the effect of drugs used to suppress the immune system. 
  • Sedatives: Ashwagandha may cause sleepiness and slow breathing, so taking it in combination with sedatives may increase these effects.
  • Thyroid hormone: Because ashwagandha might increase the body’s production of thyroid hormone, taking it with thyroid hormone pills might result in excessive levels of thyroid hormones.

What To Look For

The FDA doesn’t regulate oral supplements, so it can be difficult to determine the safety of certain products. However, several independent certifying bodies test supplements for safety and to ensure they contain what’s on the label. Look for a stamp from the U.S. Pharmacopeia, ConsumerLab, NSF International, or US Pharmacopeial Convention (USP).

Most ashwagandha products come from both wild and cultivated plants in India, but the plants can grow in any warm, dry climate. There’s no indication that the origin of the plant matters when it comes to effectiveness, and both wild and cultivated ashwagandha are generally safe to consume and use on your skin.

Can You Take Too Much Ashwagandha?

As with most supplements, you don't want to consume excessive amounts of ashwagandha. Larger doses of oral ashwagandha supplements may cause digestive issues such as:

In one study, participants who took 1,200 mg of ashwagandha daily for six weeks reported constipation as a side effect more often than people who took 900 mg of the herb daily. However, participants in both groups also ingested different doses of other supplements at the same time, so it's unclear whether the higher dose of ashwagandha or a different supplement caused constipation.

Ashwagandha Side Effects

Most people who take ashwagandha won’t have side effects. Some people may experience mild effects, including:

  • Indigestion
  • Nausea
  • Vomiting
  • Diarrhea
  • Constipation
  • Itchy rash
  • Lack of appetite

Although rare, taking ashwagandha supplements may cause liver issues that manifest as itchy skin or jaundice.

A Quick Review

Ashwagandha is an herb used for thousands of years in traditional medicine, primarily in India. It's also widely used around the world in various forms, including capsules, powders, and topical creams.

People might use ashwagandha as a cure-all treatment for a myriad of conditions, but modern research is still examining its effectiveness for different conditions. Some research suggests its benefits include reducing anxiety, boosting cognitive functions, increasing strength, and improving sleep quality.

While ashwagandha is generally safe for short-term use, its long-term effects are unknown. Always speak to a healthcare provider before ingesting it or applying it topically to your skin.

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