Ashwagandha is a traditional stress reliever that is being investigated for potential benefits to memory and immune function, but some people don’t tolerate it well. What do people use it for? What does the science say? Learn more here.

What is Ashwagandha?

Like most supplements, ashwagandha is not approved by the FDA for any purpose. The evidence presented here is considered preliminary and insufficient to justify medical use [1].

To avoid unexpected interactions or other adverse events, talk to your doctor before incorporating ashwagandha into your daily regimen.

“Horse Smell”

Ashwagandha (Withania somnifera) is a member of the Solanaceae or nightshade family of plants. It goes under several other names, such as Indian ginseng, poison gooseberry, or Indian winter cherry [2].

The name Ashwagandha can be traced back to ancient Sanskrit. It translates to “smell of a horse” (ashwa “horse” and gandha “smell”) since the scent of its roots is similar to that of horse urine. Others say its name indicates it will make you “strong like a horse,” and there may be truth to this claim [2, 3].

Ashwagandha is a powerful adaptogenic herb. Adaptogens increase the body’s resistance to stress, offsetting detrimental effects and helping to balance bodily functions and the immune response [2].

Ashwagandha or Indian ginseng is a powerful adaptogen that makes you more resistant to stress and is believed to balance your immune response.



  • Combats the effects of stress on mind and body
  • Stimulates the immune system and fertility
  • Reduces pain, inflammation, and oxidative damage
  • Improves memory and physical performance
  • Protects the brain, liver, lungs, and kidneys
  • May help with diabetes, infections, and cancer


  • Has unpleasant taste
  • May increase thyroid hormones
  • May cause digestive issues
  • Not enough clinical testing to justify medical use
  • Insufficient evidence for a lot of claims
  • No safe & effective dose has been determined

Traditional Uses

In the Indian traditional medicine system of Ayurveda, ashwagandha is seen as a broad-spectrum remedy. It’s classified as a Rasayana or rejuvenator. These are some of the traditional uses [2, 4, 5]:

  • The roots are used as a tonic, aphrodisiac, diuretic, antiparasitic, astringent, and stimulant
  • The leaves are recommended for fever and painful swelling
  • The seeds are antiparasitic while the flowers are used as an astringent, diuretic, and aphrodisiac and have detoxifying effects
  • The berries and tender leaves are applied externally to tumors, ulcers, and wounds
  • Other useful parts are the stem, fruit, and bark

Ashwagandha root is also used to restore health in women after giving birth and to thicken and increase the nutrition of breast milk. Despite its centuries-long use in India, Ashwagandha has only recently gained scientific recognition in the West [6, 2].

In Ayurveda, ashwagandha is a rejuvenator and broad-spectrum tonic for various health conditions. It is believed to have antiparasitic, aphrodisiac, diuretic, and detox effects.

Active Components

Ashwagandha contains a range of active components, including a unique family of compounds called withanolides, as well as alkaloids, saponins, terpenoids, flavonoids, tannins, phenols, and resins [7, 4].


Among Ashwagandha’s components, the most biologically active are the withanolides, and the best studied is withaferin A. This component has recently become a focus of research because of its ability to hinder the growth of tumors [8, 9, 10].

Withanolides are steroid lactones. These naturally occurring plant steroids decrease inflammation, promote cancer cell death, and halt tumor progression [9, 8].

Withaferin A is a powerful antioxidant and anti-inflammatory withanolide. Researchers are currently investigating whether it could be used to fight glioblastoma, the most common and deadliest brain cancer [8].

One of the main obstacles to using withaferin A as a therapeutic agent is low bioavailability, meaning that only a small amount of ingested withaferin A makes it into the bloodstream. Some researchers have proposed loading withaferin A into a biodegradable implant to deliver it more effectively to the blood [8, 11].

Withanolides are unique compounds from ashwagandha researched for their anti-inflammatory and anticancer effects.


Sitoindosides are a group of antioxidant saponins. They are of interest to researchers because they may ease psychological stress and prevent cognitive defects [12, 3, 2].

Sitoindosides VII and VIII appear to have the most promise as future therapeutic agents [12, 3].

Potential Benefits of Ashwagandha

1) Anxiety & Stress

Of all of the potential benefits of ashwagandha, this has the most robust body of evidence to support it, but it hasn’t been approved by the FDA! It’s important to talk to your doctor before taking ashwagandha for any reason.

Ashwagandha is traditionally used as a tonic to calm the nerves. In two studies of 116 chronically-stressed people, the root extract improved stress, well-being, and happiness; it also reduced cortisol levels [2, 13, 3].

In a study of 39 people, ashwagandha extract was slightly effective for people with anxiety [14].

In several animal studies, Ashwagandha was helpful against anxiety and depression and for improving stress tolerance [15, 16, 17, 18, 2].

Ashwagandha combats stress, improves mood, and may relieve anxiety.

2) Memory

Ashwagandha root extract improved memory in 50 people with mild cognitive impairment. The extract also improved working memory in another study of 53 people [19, 20].

In rats, Ashwagandha protected against memory impairment due to PTSD and the lack of oxygen (hypoxia) [21, 22].

3) Fat Loss & Muscle Growth

Ashwagandha root extract reduced food cravings, eating, and body weight in a study of 52 people [13].

In three studies with over 100 people, ashwagandha extract in combination with resistance training [23, 24, 25]:

  • Reduced body fat
  • Increased muscle strength
  • Boosted testosterone
  • Reduced body fat

4) Endurance

In a trial of 49 healthy athletic adults, Ashwagandha extract improved endurance and self-reported physical health after 12 weeks [26].

It had the same effect on 40 elite cyclists after 8 weeks of supplementation [27].

5) Diabetes

In a small trial of 12 people, Ashwagandha decreased blood sugar levels as effectively as diabetes medication, without significant adverse side effects [28].

Ashwagandha also reduced blood sugar in several animal studies. In some of these studies, HbA1c (a measure of long-term blood sugar) and insulin levels improved as well [29, 30, 31, 32].

In other animal studies, Ashwagandha reduced the severity of complications from diabetes, such as testicular dysfunction, cataracts, and nerve pain. Supplementation also improved antioxidant status; this is helpful because excess glucose creates oxidative stress [33, 34, 35, 36].

Ashwagandha may help with diabetes by reducing blood sugar and insulin levels and enhancing antioxidant defense, but more research is required to determine whether it’s effective for this purpose.

6) Heart Health

Ashwagandha can reduce blood pressure and cholesterol and prevent atherosclerosis, thus improving heart health [31, 37, 38].

In animal studies, Ashwagandha reduced the risk of stroke and heart attacks. It also decreased triglyceride levels and protected against oxidative damage due to chemotherapy [39, 40, 41].

7) Infections


In a study of 133 people with tuberculosis, Ashwagandha and other herbals in combination with antibiotics relieved coughing and fever better than antibiotics alone. In another study of 99 people with tuberculosis, Ashwagandha improved symptoms, inflammation, and body weight [42, 43].

In mouse and cell studies, Ashwagandha has inhibited or killed bacteria such as Salmonella and Staphylococcus aureus [44, 45, 46].


An herbal remedy containing Ashwagandha sped up recovery from viral hepatitis in 29 patients [47].

Ashwagandha has also shown antiviral activity against HIV, herpes, and Infectious Bursal Disease virus in cell-based studies [48, 49, 50, 51].


Ashwagandha inhibited the growth of multiple species of fungus (Aspergillus flavus, Fusarium oxysporum, and Fusarium verticillioides) in a cell study [45].


Ashwagandha has shown anti-parasitic activity against Leishmania and Malaria in animal studies [52, 53, 54].

According to cell studies, ashwagandha may help fight bacteria, fungi, and viruses. However, more studies in animals and, eventually, in humans will be required.

8) Symptoms of OCD & ADHD


In a study of 30 people with obsessive-compulsive disorder (OCD), Ashwagandha extract taken with standard treatment reduced their symptoms more than medication alone [55].

Ashwagandha also effectively treated the symptoms of OCD in mice [56].


ADHD is usually treated with psychostimulants, such as Ritalin. However, their long-term safety has been questioned in several studies. A safer alternative would be preferable for many parents [57, 58].

An herbal mix containing Ashwagandha, peony, Gotu Kola, spirulina, bacopa, and lemon balm improved response time, impulsivity, and focus in a study of 120 children with ADHD, with no adverse side effects reported [58].

No studies have yet investigated the effect of Ashwagandha alone in ADHD.

Ashwagandha may reduce symptoms of OCD and ADHD, but more trials are needed to confirm its effectiveness.

9) Schizophrenia

In a pilot trial of 11 people, Ashwagandha reduced the severity of sensory problems experienced by schizophrenia patients [59, 60].

However, it did not help with feelings of isolation or depression in another study of 25 schizophrenic patients [61].

10) Pain

Ashwagandha reduced pain, stiffness, and disability in 60 people with knee joint pain. Ayurvedic treatment containing ashwagandha reduced pain, joint tenderness, and swelling in a study of 86 people with rheumatoid arthritis [62, 63].

In another study of 42 people, an herbal mixture containing Ashwagandha, Indian frankincense, turmeric, and zinc reduced pain from osteoarthritis. Ashwagandha also relieved pain in three rodent studies [64, 65, 66, 67].

11) Reproductive Health


Ashwagandha may reduce the complications of menopause. In a trial of 51 menopausal women, ashwagandha reduced symptoms such as hot flashes, mood fluctuations, sleep issues, irritability, and anxiety [68].

In 50 healthy women, Ashwagandha improved self-reported measures of sexual function such as arousal, lubrication, orgasm, and satisfaction [69].

Ashwagandha with Tribulus terrestris restored hormone balance in rats with polycystic ovary syndrome (PCOS) [70].


In a clinical trial of 150 men, Ashwagandha reduced oxidative stress, increased testosterone, and lowered FSH. These hormonal changes encourage the production of new sperm cells. It also improved sperm count and mobility [71].

In 46 men with low sperm count, Ashwagandha increased [72]:

  • sperm count, by 167%
  • semen volume, by 53%
  • sperm motility, by 57%

It recovered semen quality in 180 infertile men [73].

Ashwagandha may improve reproductive health in both women and men by normalizing hormone levels, semen quality, and sexual function. However, more studies will be required to confirm any benefit.

12) Sleep

The root or whole plant extract has been used as a sleep agent in Ayurveda. A mouse study found that triethylene glycol is the active component of Ashwagandha responsible for sleep induction [74].

Ashwagandha improved sleep quality in 6 out of 18 healthy people. It also improved sleep in rats through activating the GABA pathway [75, 76].

Sleep loss is unhealthy and leads to increased levels of reactive oxygen species (ROS) and cell death in the brain. Interestingly, Ashwagandha prevented the negative effects of sleep deprivation in rodents, likely through antioxidant mechanisms [77, 78, 79].

Ashwagandha may help you fall asleep and improve your sleep quality. It may also reduce the consequences of sleep deprivation. However, as usual, more studies are required.

13) Immunity

In a small trial of 5 people, Ashwagandha extract improved the immune response by activating white blood cells. In two other trials (a total of 142 people), an herbal mix containing Ashwagandha increased the activity of natural killer cells, white blood cells specialized to fight tumors and viruses [80, 81].

In mice, Ashwagandha extract enhanced immunity by activating bone marrow cells, macrophages, and lymphocytes [82, 83].

It increased the levels of Th1 cytokines and prevented the depletion of white blood cells in stressed mice [84].

Finally, in a combined mouse and cell study, Withaferin A inhibited the activity of myeloid-derived suppressor cells (MDSCs). These dysfunctional immune cells can stimulate tumor growth and prevent the immune system from attacking cancer cells [85, 86].

Ashwagandha may stimulate the immune system to fight infections and cancer, but more clinical trials are needed.

14) Gut Health

In a single case report, an Ayurvedic medication containing Ashwagandha helped treat constipation, stomach pain, and vomiting [87].

An enema of Ashwagandha restored the health of the intestinal lining in rats with IBD [88].

Note, however, that one animal study and a single case study of an herbal blend cannot be considered strong evidence. We need additional studies before making any definitive claims about Ashwagandha’s effect on the digestive system.

15) Adrenal Function

Congenital adrenal hyperplasia (CAH) is an inborn dysfunction of enzymes that control hormone production in the adrenal gland. It results in a deficiency of cortisol and aldosterone and an excess of male hormones. Symptoms include excess facial hair, acne, hair loss, menstrual irregularity, and infertility.

In two case studies, Ashwagandha improved the symptoms and hormone levels of elderly women with CAH [89, 90].

Controlled trials should confirm this benefit.

16) Oxidative Stress

Withanolides, the Ashwagandha active compounds, are potent antioxidants. In a study on human cells, Ashwagandha improved markers of age-related oxidative stress (FOXO3A and SIRT3), suggesting it may prevent premature aging [91].

In rat studies, Ashwagandha boosted the body’s antioxidants, including superoxide dismutase (SOD), catalase, and glutathione. It also prevented kidney injury due to dehydration and oxidative damage due to chemotherapy [92, 93, 94].

Longevity Studies

Ashwagandha’s antioxidant properties may potentially increase longevity. It increased the antioxidant enzymes and reduced markers of oxidative stress in a study of 30 people [95].

In three studies, Ashwagandha extended the lifespan of a worm (C. elegans) often used to study models of longevity [96, 97, 98].

Ashwagandha increases the body’s natural antioxidant capacities, which may promote longevity.

17) Brain Health

In cell studies, Ashwagandha promoted the growth of brain cells and stimulated neuronal regeneration [99, 2].

Ashwagandha can reduce oxidative damage from drugs and protect against excess glutamate. It helped control epileptic seizures in mice and treat dyskinesia (involuntary movement) in rats [100, 101, 102, 103, 104].

Alzheimer’s Disease

Alzheimer’s disease is a form of dementia caused by deposits of beta-amyloid proteins and loss of brain cells. Ashwagandha improved cognitive function and reduced beta-amyloid deposits in mouse models of Alzheimer’s [105, 106].

Parkinson’s Disease

Parkinson’s disease is a neurodegenerative disease involving progressive loss of dopamine neurons. In a mouse model of Parkinson’s, Ashwagandha normalized dopamine levels and reduced free radical damage to brain cells [107, 108].

Huntington’s Disease

Huntington’s disease is a genetic disorder that causes oxidative damage and a progressive breakdown of brain cells [109].

In rat studies, Ashwagandha protected against oxidative stress and mitochondrial dysfunction, suggesting it could be useful in diseases such as Huntington’s [109, 110, 111].

Ashwagandha may protect against nerve damage and improve the symptoms of Alzheimer’s and Parkinson’s disease. Clinical studies should confirm these benefits.

18) Cancer

Ashwagandha improved fatigue and quality of life in a trial of 100 cancer patients receiving chemotherapy [112].

Several animal and cell studies have shown that the constituents of Ashwagandha, in particular withaferin A, inhibit or destroy cancer cells [113, 2, 114, 10].

What’s more, Ashwagandha can make the chemotherapy drug paclitaxel more effective against lung cancer, according to mouse studies [115, 116, 117].

In cell and animal studies, Ashwagandha has slowed or reversed the growth of several cancers, including:

Ashwagandha may support chemotherapy and improve quality of life. According to cell and animal studies, it might also block the growth of different cancers. These are early results, however, and much more robust research will be required.

19) Bone Health

Bone health issues often arise after menopause, when low levels of estrogen disrupt bone structure. In mice with estrogen deficiency, Ashwagandha prevented bone loss and stimulated new bone formation [134, 135].

It improved bone building in calcium-deficient rats and chickens and increased bone collagen in arthritic rats [136, 137, 138, 139].

In cell studies, Ashwagandha stimulated bone formation and protected cartilage [140, 141].

According to animal studies, ashwagandha may prevent bone loss due to menopause and calcium deficiency. This potential benefit has not yet been studied in humans.

20) Kidney Damage

In rat studies, Ashwagandha protected the kidneys against toxicity of several chemicals, including:

  • Bromobenzene (toxic chemical) [142]
  • Carbendazim (antifungal) [143]
  • Gentamicin (antibiotic) [144, 145]
  • Lead (heavy metal) [146]
  • Streptozotocin (chemotherapy) [147]

It also protected against kidney damage caused by dehydration [93].

21) Liver Health

Ashwagandha protected the liver against damage from radiation and heavy metals in rats [148, 149].

It increased the bile content in rats with high cholesterol and decreased certain liver enzymes that indicate tissue damage [39, 150].

22) Respiratory Health

Polysaccharides extracted from Ashwagandha suppressed coughing in guinea pigs as effectively as codeine [151, 152].

In baby rats, withaferin A also protected the lungs against inflammation and oxidative stress caused by toxic bacterial lipopolysaccharides (LPS). Future trials will clarify whether Ashwagandha or its compounds may be helpful against respiratory infections [153].

23) Autoimmunity

Lupus is an autoimmune disease that involves high levels of inflammation. In a mouse study, Ashwagandha reduced inflammatory markers that tend to be high in lupus and other autoimmune diseases, including IL-6 and TNF-alpha [154, 155].

24) Traditional Use as a Venom Antidote

In India, Ashwagandha is used to treat snake bites and scorpion stings. A compound from Ashwagandha inhibits cobra and viper venom in mouse and cell studies [156, 157, 2].

25) Morphine Dependence

Ashwagandha may help prevent people from developing a dependence on morphine, and it may help people who are already dependent wean themselves off of morphine without severe withdrawal symptoms [158].

In a rat study, Ashwagandha extract reduced withdrawal symptoms and prevented morphine dependence. In neurons exposed directly to morphine, Ashwagandha extract prevented the downregulation of opioid receptor activity. Thus, Ashwagandha may be useful to prevent dependence when opioid painkillers are necessary [159, 160, 158].

26) Mild Hypothyroidism

Mild hypothyroidism, or low thyroid hormones, occurs in 3-8% of people and is especially common in women over 55. Treatment with levothyroxine, a synthetic form of the thyroid hormone T4, often comes with more risks than benefits; thus, many people with mild hypothyroidism go untreated [161].

In a trial of 50 people with mild hypothyroidism, Ashwagandha extract normalized TSH and thyroid hormones (T3 and T4) [162].

It also increased thyroid hormones in hypothyroid rodents and reduced oxidative stress and inflammation [163, 164].

Ashwagandha may safely increase thyroid hormones, but the available research is scarce.

How to Use Ashwagandha


Root extract: most clinical studies have used 120-1000 mg daily, with the most common dose being 300 mg twice daily.

Whole root: clinical doses range between 2-10 g of powdered root daily, with an average of 5 g per day.

Safety & Side Effects

Ashwagandha is generally safe when taken in recommended dosages. Large doses of Ashwagandha can cause abdominal discomfort and diarrhea. Because Ashwagandha is mildly sedative, be careful about taking other sedatives with it.

Ashwagandha also has the potential to raise thyroid hormone levels, and people with hyperthyroidism may want to avoid it [25, 165, 166].

Supplement Forms

Ashwagandha is available in many forms, such as powder, capsules, pills, or essential oil. It can also be made into a tea or ointment using honey or ghee. Commercial Ashwagandha is often combined with black pepper extract, another strong antioxidant.

In Ayurveda, the fresh roots are sometimes boiled in milk prior to drying to leach out undesirable components [167].

Taste & Smell

Ashwagandha is a famously pungent herb. Its name means “smell of horse”, and some users say it can be overwhelming. If you are concerned about the smell and taste of Ashwagandha but still want to try it, look for capsules of dry extracts [3, 2].


Ashwagandha is a powerful and versatile traditional herb known for its ability to relieve anxiety and stress. Its active components have been investigated for cognitive and emotional benefits; they may also help manage neurological conditions from Alzheimer’s to schizophrenia.

The antioxidant properties of ashwagandha prevent tissue damage in the liver, lungs, brain, and kidneys. It also prevents hormonal imbalances and improves sexual function in both men and women. Ashwagandha is safe and effective at daily doses of up to 1000 mg of root extract or 10 g of powdered root.

For the best results, start with low doses and work your way up, take a high-quality standardized supplement, and do your best to reduce stress. Ashwagandha should not be taken with other sedatives or by people with high thyroid hormones.


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About the Author

Jimmy Julajak, MSc

MS (Psychology)

Jimmy got his MSc from the University of Copenhagen.

Jimmy is a psychologist and researcher. He is particularly interested in the workings of the brain and strategies for improving brain health. He believes that people shouldn't hand over the responsibility for their health only to their doctors. His aim is to empower each person with easy-to-understand, science-based health knowledge.

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