Ashwagandha: Uses, Benefits, Dosage, and Side Effects
Medically Reviewed by Anthony Dugarte, MD
Published on November 10, 2021
Ashwagandha isn’t just a fun word to say. This ancient adaptogenic herb may offer several health benefits, such as supporting brain health, reducing stress and anxiety, and supporting male fertility.
Ashwagandha (Withania somnifera) is an ancient herb of the Indian Ayurvedic system of medicine. Other names for ashwagandha include “Indian Winter Cherry” or “Indian Ginseng.” (1)
It’s classified as an adaptogen, which means it may help your body adapt to and fight off negative stressors. (2)
It’s also considered a nervine tonic, an herb used primarily to target and calm the central nervous system.
Used for over 3,000 years in Ayurvedic and indigenous medicine, ashwagandha has been historically given to children as a tonic to promote well-being and to older adults to promote longevity. (3)
The ashwagandha plant originates in North Africa and India.
It’s a small, yellow-flowered shrub from which extracts and powders of its roots or leaves are used to make medicinal preparations and supplements.
Most of the purported health benefits of using ashwagandha have been attributed to compounds called withanolides.
Ashwagandha is a popular supplement, often taken as a capsule, powder, gummy, or liquid.
Most supplements are made using ashwagandha root extract.
People take ashwagandha supplements for a variety of reasons. The following are eight known health benefits of ashwagandha:
1. May Support Healthy Blood Sugar Control
Some studies have demonstrated the ability of ashwagandha supplementation to reduce high blood sugar levels and even improve insulin sensitivity.
Together, these factors may help improve blood sugar management, though more research using more extensive human trials is needed. (4)
One study found that standardized ashwagandha root and leaf extract, given to people for 60 days in doses of either 125 mg once per day, 125 mg twice per day, or 250 mg twice per day, was effective in significantly reducing mean fasting blood glucose compared to people given a placebo. (6)
In a 2013 randomized, double-blind, placebo-controlled study conducted among individuals with schizophrenia, those treated with ashwagandha for four weeks saw their blood sugar levels drop by an average of 13.5 mg/dL. (7)
In contrast, the placebo group had a 4.5 mg/dL reduction.
Research shows that ashwagandha can help support normal blood sugar and improve insulin sensitivity in people with diabetes and those without.
2. May Help Reduce Stress
Taking ashwagandha may help reduce the levels of cortisol in your body. Cortisol is a stress hormone released when your blood sugar is low, or your body is otherwise under stress.
In a 2008 study published in JANA, researchers found that when ashwagandha supplementation was given to chronically stressed adults, they experienced more significant reductions in cortisol than a placebo group. (6)
Those who received the highest doses of ashwagandha, 250 mg twice per day for 60 days, saw approximately a 30% reduction in their cortisol levels.
Additionally, a 2012 prospective study among 64 chronically stressed adults found that when given 300 mg of high-concentration full-spectrum ashwagandha root extract twice per day for 60 days, the individuals experienced significant improvement in stress levels and quality of life. (8)
In fact, they reported a 69% reduction in both anxiety and insomnia, compared to just an 11% reduction in the placebo group.
And in a six-week-long 2000 study among 39 people divided into an ashwagandha group and a placebo group, 88% of those who took ashwagandha experienced reduced anxiety. (9)
Only around half of the placebo group reported improvement.
Ashwagandha may help improve the burdens of stress and anxiety by regulating chemical signaling in the nervous system and even blocking stress pathways.
3. May Help Boost Mood
The activity of ashwagandha in the brain may also help alleviate symptoms of depression, though there’s not a ton of research on the subject.
In one 2012 study we previously discussed, people who took a twice-daily capsule of 300 mg of high-concentration full-spectrum ashwagandha root extract experienced a 79% reduction in severe depression symptoms. (8)
In comparison, the placebo group in this study actually reported a 10% increase in depression.
Ashwagandha may help improve symptoms of depression, but further research is needed.
4. May Offer Anticancer Activity
A compound in ashwagandha called withaferin has been observed to promote programmed cancer cell death in test tube studies. (10)
It may also slow the formation and progression of new cancer cells.
Some researchers suggest that withaferin does this by making cancer cells less resistant to their own death, possibly by increasing the presence of reactive oxygen species inside of them that cause damage. (11)
While human studies are lacking, animal studies have demonstrated these activities of withaferin.
For instance, a 2014 study published in PLoS One saw nearly an 80% reduction in ovarian tumor growth when mice were given either withaferin by itself or in combination with anti-cancer medication. (12)
Active ingredients in ashwagandha may help reduce the risk and slow the progression of different types of cancer.
5. May Support Heart Health
Compounds in ashwagandha may help lower levels of blood fats that may be a risk factor for heart disease when elevated.
One 2007 study among hypercholesteremic rats found that when ashwagandha root extract was added to their diet in doses of 0.75 and 1.5 grams per day, they saw significant reductions in total cholesterol and triglycerides at respective rates of 53% and 44%. (16)
Some human studies have found similar results, though not quite as substantial. (7)
In a 60-day study conducted among adults with chronic stress, those given the highest dose of ashwagandha root extract, 500 mg per day, experienced an 11% reduction in triglycerides and a 17% reduction in LDL “bad” cholesterol. (6)
Ashwagandha has benefits for heart health, possibly lowering blood lipid levels.
6. May Support Male Fertility
Taking ashwagandha may help support fertility, particularly in males.
In one study, researchers concluded that one reason behind these male fertility benefits was that ashwagandha effectively reduced oxidative stress, decreased levels of various oxidants, and increased antioxidants in the body. (17)
And in a 2009 study, researchers examined the effects of ashwagandha supplementation on stress-induced male fertility problems. (18)
Infertile males who had normal sperm production and were either heavy smokers, experiencing significant psychological stress, or were either infertile for no known cause, were given 5 grams of ashwagandha per day for three months.
At the beginning and end of the study, various biochemical and stress parameters were measured.
Ashwagandha supplementation was found to effectively reduce stress, improve antioxidant levels, and improve overall semen quality in most men.
Following the study, 14% of the men and their partners were able to conceive.
A similar 2013 clinical trial, in which 180 infertile men were given 5 grams of ashwagandha root powder for three months, found that the herb was beneficial enough to be recommended for clinical management and treatment of infertility among men. (19)
Ashwagandha may have benefits for male fertility by helping reduce oxidative stress.
7. May Promote Healthy Brain Function
Cognitive function may decline with age, disease, or injury. Some studies have found promise in the protective effects of ashwagandha.
Supplementing with ashwagandha appears to increase antioxidant activity in the brain and consequently help protect it from oxidative stress and free radicals that can worsen cognition. (20)
In a 2017 randomized controlled trial among 50 adults, 300 mg of ashwagandha root extract twice daily for eight weeks resulted in significant cognitive improvements in the form of memory, attention span, and memory. (21)
Another study found that 250 mg of ashwagandha extract given twice daily for just two weeks also improved brain function among 20 healthy men. (22)
Ashwagandha may help support cognitive function by helping reduce oxidative stress to the brain.
8. May Help Increase Muscle Strength
Interestingly, taking ashwagandha may also be helpful if you’re looking to build muscle mass and improve your overall strength.
In one 2012 study published in the Journal of Ayurveda and Integrative Medicine, 18 healthy adults were given ashwagandha root powder in two divided doses daily for 30 days. (23)
The dose was increased incrementally every ten days, starting at 750 mg and ending at 1,250 mg.
At the end of the study, the participants had experienced a significant increase in muscle strength, as well as a loss of total body fat percentage.
Another 8-week randomized controlled trial among 57 young males found that ashwagandha root extract supplementation, in doses of 300 mg twice daily, was effective for significantly increasing muscle strength and size. (24)
Additionally, they experienced substantial losses in body fat percentage compared to a placebo group.
Ashwagandha supplements may help increase muscle mass and strength.
Ashwagandha is available in several forms and doses, which can vary between brands and purposes.
It appears that the most common doses of standardized ashwagandha root extract are around 250–600 mg taken 1–2 times daily, often in the form of a capsule.
One study among healthy adults found that even taking up to 1,250 mg per day, in two divided doses, showed no adverse side effects. (23)
But other research has found that taking doses of 1,000 mg per day or more can cause upset stomach, vomiting, and diarrhea for some people. (25)
The best recommendation is to follow the dosing instructions on the supplement you choose and to speak to your healthcare provider before you begin taking ashwagandha.
When choosing an ashwagandha supplement, it’s important to find a reputable brand that uses high-quality ingredients.
Look for one that bears an official third-party testing seal whenever possible and check the brand website to see if they provide scientific evidence behind their formulation.
It can also be helpful to check for independent expert reviews of the products.
Both products use KSM-66, the highest concentration of branded ashwagandha extract on the market.
Their ingredients also have evidence supporting their potential to help reduce stress, improve sleep and memory, increase strength, and support immunity.
The long-term effects of using ashwagandha are unknown, and more human research is needed on its specific uses and benefits.
However, currently available research shows that ashwagandha is generally considered to be safe for most healthy people, as long as you’re taking it in the recommended dosages. (23)
Some populations shouldn’t use it due to a lack of research on safety. These include pregnant and breastfeeding women as well as people with autoimmune diseases. (26)
People taking certain medications, such as drugs for blood sugar control or thyroid hormones, should also avoid ashwagandha as it may interact with these.
I would suggest looking for an ashwagandha supplement that bears an official third-party testing seal, indicating that it has been independently verified to contain what it claims and has been evaluated for quality and safety.
Examples include seals from NSF International, ConsumerLab, or USP.
As with all herbs and supplements, please speak with your healthcare provider for individual recommendations before beginning to take ashwagandha to make sure it’s safe and appropriate for you.
Frequently Asked Questions About Ashwagandha
What is ashwagandha good for?
Ashwagandha has been used for thousands of years for numerous ailments and even to promote longevity.
Currently, available research suggests it may be beneficial for things like supporting healthy blood sugar control, cognitive function, immune function, heart health, stress response, and muscle strength.
However, the effects of supplements are never guaranteed, and benefits can be vastly different between individuals.
Is ashwagandha good for anxiety?
Ashwagandha is considered an adaptogenic herb, meaning that it may help your body adapt and respond to stressors.
Studies have shown that ashwagandha may help reduce reported stress and anxiety levels by modifying chemical signaling in the central nervous system.
Is ashwagandha safe to use?
Most research indicates that ashwagandha is generally safe to use for healthy individuals.
Due to lack of research and potential drug interactions, it should not be used by pregnant and breastfeeding women or people who take medications for lowering blood sugar or thyroid health.
Please speak to your healthcare provider before starting ashwagandha to ensure it’s safe and appropriate for you.
How do you take ashwagandha?
Ashwagandha is most often sold as a root extract in the form of a powder, a capsule, a gummy, or a liquid dropper.
Instructions for use depend on the specific product.
Powdered extracts may be blended into smoothies, and liquid droppers may be taken either directly on the tongue or mixed with a small amount of your favorite beverage.
How long do you need to take ashwagandha to see results?
Ashwagandha doesn’t yield immediate results, and your experience may be different from someone else’s. For many people, it can take multiple days to weeks before an effect is experienced.
For instance, one 2019 study among 60 people found that it took ten weeks to feel the full effects of 300 mg taken daily on their sleep quality.
When is the best time to take ashwagandha?
In general, you can take ashwagandha at any time of day and when it makes the most sense within your routine.
However, as with any supplement, it may trigger stomach discomfort for some people, so you may want to take it with breakfast in the morning or with a snack.
Others may choose to take ashwagandha right before bedtime if taking it to help promote better sleep.
What to look for in an ashwagandha supplement?
When looking for an ashwagandha supplement, try to find one that bears an official third-party testing seal, such as from NSF International, ConsumerLab, or USP.
However, this isn’t always available, so it’s also helpful to review the brand itself or look for expert reviews online. Look at their website and see what research they have made available to consumers.
It’s also important not to choose one that exceeds typical dosing for ashwagandha, which seems to be between 250–600 mg per day, and not to exceed 1,000 mg per day for safety.
Additionally, choose an option that can fit into your routine and budget. For instance, some products may recommend taking 1–2 servings per day, while others may suggest upwards of 3–6 per day.
Ashwagandha is an ancient adaptogenic herb that has been used for various health conditions for thousands of years.
Current research shows promise in using ashwagandha for improving stress and anxiety, supporting cognitive function, offering antioxidant activity, improving male fertility, and improving blood sugar control.
More extensive human research would be helpful, as many of the studies are small or conducted with animals.
Most data indicates that ashwagandha is generally safe for most healthy people. Still, it should be avoided in pregnancy and among people taking blood sugar or thyroid medications due to lack of research and potential drug interactions.
As with all supplements, it’s best to choose an ashwagandha supplement that bears an official third-party testing seal and speak with your healthcare provider before adding it to your routine.
At WellnessVerge, we only use primary references for our articles, including peer reviewed medical journals or well-respected academic institutions.
- An Overview on Ashwagandha: A Rasayana (Rejuvenator) of Ayurveda:
- Adaptogenic and Anxiolytic Effects of Ashwagandha Root Extract in Healthy Adults: A Double-blind, Randomized, Placebo-controlled Clinical Study:
- Steroidal lactones from Withania somnifera, an ancient plant for novel medicine:
- Hypoglycemic, diuretic and hypocholesterolemic effect of winter cherry (Withania somnifera, Dunal) root:
- Hypoglycemic activity of withanolides and elicitated Withania somnifera:
- A Standardized Withania Somnifera Significatly Reduces Stress-Related Parameters In Chronically Stressed Humans; A Double-Blind, Randomized, Placebo-Controlled Study:
- Effects of Withania somnifera in patients of schizophrenia: A randomized, double blind, placebo controlled pilot trial study:
- A prospective, randomized double-blind, placebo-controlled study of safety and efficacy of a high-concentration full-spectrum extract of ashwagandha root in reducing stress and anxiety in adults:
- A double-blind, placebo-controlled evaluation of the anxiolytic efficacy ff an ethanolic extract of withania somnifera:
- Molecular targets and mechanisms of cancer prevention and treatment by withaferin a, a naturally occurring steroidal lactone:
- Withaferin A Induces Cell Death Selectively in Androgen-Independent Prostate Cancer Cells but Not in Normal Fibroblast Cells:
- Withaferin a alone and in combination with cisplatin suppresses growth and metastasis of ovarian cancer by targeting putative cancer stem cells:
- Effect of Withania somnifera root extract on spontaneous estrogen receptor-negative mammary cancer in MMTV/Neu mice:
- Stabilization of membrane bound enzyme profiles and lipid peroxidation by Withania somnifera along with paclitaxel on benzo(a)pyrene induced experimental lung cancer:
- Immunomodulatory effects of Withania somnifera on azoxymethane induced experimental colon cancer in mice:
- Hypocholesteremic and antioxidant effects of Withania somnifera (Dunal) in hypercholesteremic rats:
- Withania somnifera improves semen quality by regulating reproductive hormone levels and oxidative stress in seminal plasma of infertile males:
- Withania somnifera Improves Semen Quality in Stress-Related Male Fertility:
- Efficacy of Withania somnifera on seminal plasma metabolites of infertile males: a proton NMR study at 800 MHz:
- Oxidative stress induced NMDA receptor alteration leads to spatial memory deficits in temporal lobe epilepsy: ameliorative effects of Withania somnifera and Withanolide A:
- Efficacy and Safety of Ashwagandha (Withania somnifera (L.) Dunal) Root Extract in Improving Memory and Cognitive Functions:
- Effect of standardized aqueous extract of Withania somnifera on tests of cognitive and psychomotor performance in healthy human participants:
- Exploratory study to evaluate tolerability, safety, and activity of Ashwagandha (Withania somnifera) in healthy volunteers:
- Examining the effect of Withania somnifera supplementation on muscle strength and recovery: a randomized controlled trial:
- Safety and clinical effectiveness of Withania Somnifera (Linn.) Dunal root in human ailments:
- Critical evaluation of ayurvedic plants for stimulating intrinsic antioxidant response: