Ashwagandha (Withania somnifera)

Ashwagandha (Withania somnifera)

Feb 06, 2019

What is Ashwagandha  

Ashwagandha (Withania somnifera) is a shrub, native to the dry regions of India, with oval leaves and yellow flowers which bears small red fruits as it is from the same family as the tomato (although the small fruits of Ashwagandha are not edible). However, it is the root of the plant that has been used to promote health for over 3,000 years. Apart from India, Ashwagandha grows also in the Middle East and northern Africa. Due to its increasing popularity, Ashwagandha is now also being grown in North America. 

Ashwagandha, known also as winter cherry, is often referred to as Indian ginseng‚ because of its ability to boost energy, promote stamina and work as a natural stress reliever. 

It is the most extensively researched and most used adaptogen herb. 

In Sanskrit, the meaning of the word “Ashwagandha” implies that the herb holds the strength of a horse.  Also, Ayurveda recommends Ashwagandha as an aphrodisiac and tonic. 


Key Active Ingredients

Ashwagandha contains many phytochemicals, antioxidants and nutrients. The most studied are especially steroidal lactones known as Withanolides (Withaferin A & Withanolide D) which are believed to be responsible for the most of Ashwagandha’s health benefits. 

The Withanolides are substances with a sterol structure and are believed to be the component responsible for its apoptogenic and glucocorticoid-like effects. 

Apart from Withanolides, Ashwagandha contains sterols, phenols, alkaloids, tannins, lignans, triterpenes, resins, and flavonoids.  


Health Benefits  

The root of Ashwagandha has been known for its ability to support especially brain function and nervous system, adrenal and sexual function, helping relief stress and promoting feeling of calmness and relaxation. It’s also valued for its neuroprotective, thyroid-modulating, anti-inflammatory properties. 

Human and animal studies suggest that Ashwagandha may help protect the heart and brain from oxidative damage; reduce adrenal insufficiency; promote healthy cortisol levels; support memory and promote nerve cell regeneration; help improve insulin sensitivity, maintain normal blood sugar and cholesterol levels; improve sleep, increase muscle strength; protect the liver against lead toxicity, and support immune system function. 



Ashwagandha not only contains its own antioxidants but can boost levels and activity of all most powerful antioxidants naturally found in the body. Animals with tumours treated with Ashwagandha had increased levels of glutathione, superoxide dismutase (SOD) and catalase in the liver and skin (1,2).



Ashwagandha reduces levels of stress hormone cortisol (3,4,5). This health benefit of Ashwagandha is very important as high cortisol levels contribute to high blood sugar levels (cortisol is released when blood sugar goes too low), increased fat storage in the abdomen, increased muscle loss & weakness, premature wrinkles, cognitive impairment, suppressed immunity, etc. 

For instance, researchers from the Asha Hospital in Hyderabad who conducted a study involving 64 people suffering from chronic stress found that supplementing Ashwagandha for two months decreased stress by 44% and significantly improved mood (4). 

In a 2006 clinical trial, subjects on Ashwagandha had a 30.5% reduction in serum cortisol and a 32.5% increase in levels of dehydroepiandrosterone (DHEA), the hormone that counterbalances the activity of cortisol (6). 

In a six-week study, 88% of subjects on Ashwagandha reported a reduction in anxiety (7). 

In another experiment, Ashwagandha was able to decrease the frequency and severity of instances where stress inhibits male sexual behaviour (8). 


Adrenal Fatigue and Cortisol Balance  

The amazing, good news about Ashwagandha is that it not only lowers cortisol when it is too high (as a result of stress), but it can be also effective in treating adrenal fatigue in which case it increases cortisol when it is too low! 

In certain experiment, mice that swam in water for five hours lost significant amount of ascorbic acid (vitamin C) and cortisol due to the exercise stress. However, when the same exercising mice received Ashwagandha, the loss of cortisol and vitamin C was prevented! (9). 

Due to chronic stress adrenal glands become exhausted and do not make enough cortisol in between stressful events. And since we need small amount of this hormone all the time, we experience symptoms of adrenal fatigue caused by deficiency of cortisol. Taking Ashwagandha, however, seems to reduce the loss of cortisol, helping us to cope with adrenal fatigue symptoms. 


Sleep and Mood 

Ashwagandha promotes feeling of calmness and relaxation by enhancing GABA signalling and serotonin levels in the brain. Ashwagandha’s Latin name “somnifera” can be translated as “sleep-inducing”. 

The anti-anxiety effect of Ashwagandha may be also due to the ability of Withanolides to mimic the activity of the calming neurotransmitter gamma-aminobutyric acid (GABA) which reduces over-activity in neurons, acting as a nerve tonic and helping relax, improve mood, reduce anxiety, and promote good sleep (10). 

In the 12-week 2009 study, a standard multi-vitamin and 300 milligrams of Ashwagandha twice daily decreased anxiety levels by 55 percent without side effects or adverse reaction. Significant improvements in vitality, energy levels and overall quality of life, were also noticed (11). 

In a 2000 experimental study involving rats, Ashwagandha proved to have antidepressant properties. It was concluded that it can be used as a mood stabilizer in clinical conditions of depression. 

In a study involving 64 people suffering from chronic stress found that supplementing Ashwagandha for two months decreased stress by 44% and significantly improved mood. 

According to 60-day trial stressed adults who took 600mg of Ashwagandha extract every day reported a 79% reduction in severe depression (4). 


Cognition and Dementia 

Ashwagandha improves cognition (including memory); Withaferin A & Withanolide D (key Withanolides, steroid compounds & antioxidants in Ashwagandha) slow down progression of Alzheimer’s disease by promoting brain cell regeneration & reducing amyloid beta plaque build-up. Withanolides in ashwagandha also exert a neuroprotective effect against beta-amyloid-induced cytotoxicity (the cause of Alzheimer's). 

In one controlled study, healthy men on a daily dose of 500mg of standardized Ashwagandha extract experienced significant improvement in their reaction time and task performance (12). 

According to a 2-month study 50 adult subjects on 300mg of Ashwagandha root extract twice daily significantly improved general memory, task performance and attention (13). 



Ashwagandha protects brain cells against toxicity from glutamate. It stimulates activity in normal and damaged neurons (14), and slows, stops, reverses, or removes neuron atrophy and synaptic loss (9). 

Ashwagandha has shown neuroprotective properties; Beneficial in treatment of Motor Neurone Disease & Amyotrophic Lateral Sclerosis (“Withaferin A alleviates neuro-inflammation, decreases levels of mutated SOD in the spinal cord, reduces loss of motor neurons in the brain & spinal cord resulting in delayed disease progression & mortality.”) 

Amyotrophic Lateral Sclerosis (ALS) also known as Lou Gehrig’s disease and motor neurone disease (MND), is a progressive neurodegenerative disease slowly destroying the motor neurons in the brain and spinal cord that affect and control movements of the body. Patients diagnosed with ALS gradually lose the ability to walk, speak, and they also suffer respiratory failure. 

In ALS they mitochondria seem to not function properly, and as a result tend to create large amounts of harmful oxygen radicals or lactate that causes cells and nerve tissue to degenerate and die. If this idea is true, then, apart from Ashwagandha, treatments with higher doses of Co-enzyme Q10 and Alpha Lipoic Acid (both support mitochondrial function) and other antioxidants and nutrients such as sublingual Methylcobalamin (best form of vitamin B12), and Magnesium should be very beneficial. 

Coenzyme Q10 has already demonstrated significant therapeutic effects in transgenic mouse model of ALS and Huntington’s disease (15). 


Sex Hormones and Fertility  

There are many ways Ashwagandha can help improve levels of sex hormones in both women and man. One of them is by reducing cortisol levels. Stress has negative effect on sex hormones because our body produces cortisol from the same precursors used to make reproductive (sex) hormones, and under stress, it will rather produce cortisol instead of testosterone, progesterone and oestrogen. Ashwagandha, therefore, by reducing chronic high cortisol levels will automatically increase sex hormones, thus improving fertility and sexual health. 

Ashwagandha may improve fertility in men as it increases & normalises testosterone levels, increases sperm quality and count, and helps improve the biochemical composition of semen (5,16). 

In a 3-month study, infertile men on Ashwagandha had reduced levels of reactive oxygen radicals, resulting in reduction of sperm death, and improvements in important minerals in semen, including zinc, iron & copper (17). Studies also demonstrated that Ashwagandha helps regulate hormones vital for male reproductive health (16). 


Sexual Health  

Ashwagandha restores sex drive & reduces erectile dysfunction by increasing blood flow & testosterone levels, lowering cortisol, cholesterol & blood glucose, & promoting relaxation. 

In certain experiment, Ashwagandha was able to decrease the frequency and severity of instances where stress inhibits male sexual behaviour (8). 

Also, women can benefit from Ashwagandha. According to one trial, healthy female participants who took 300mg of Ashwagandha twice a day for 2 months experienced significant improvement in arousal, orgasm, lubrication, and number of satisfactory sexual intercourses (18). 



Ashwagandha supports healthy levels of luteinizing hormone which triggers development of the corpus luteum out of which progesterone is made (16). 


Oestrogen and Menopause 

In one study with 51 menopausal women Ashwagandha was beneficial in normalising oestrogen & reducing hot flashes, mood fluctuations, sleep issues, irritability & anxiety (19). 

Ashwagandha prevents loss of bone mineral density & helps normalise follicle-stimulating hormone which increases the risk of postmenopausal osteoporosis (16). 



Ashwagandha has thyroid-modulating properties (stimulates production of thyroid hormones when they are low or normalises when they are too high. 

Ashwagandha reversed hypothyroidism caused by metformin in mice (20). 

According to a 2017 study published in the Journal of Alternative and Complementary Medicine, Ashwagandha benefited people with underactive thyroid. During a 2-month period, the participants received 600 milligrams of Ashwagandha root extract daily, and the control group received the placebo. It was found that Ashwagandha improved serum thyroid stimulating hormone (TSH) and thyroxine (T4) levels significantly compared to placebo (21). 

Also, another trial published in 2014 in the Journal of Ayurveda and Integrative Medicine has confirmed that Ashwagandha has thyroid-enhancing properties (22). 



Energy and Athletic Performance 

Athletes need emotional support as their profession is usually very stressful and leads to adrenal fatigue, low mood and sleep problems. Therefore, apoptogenic herbs such as Ashwagandha or Rhodiola can be very beneficial for them. 

There are athletes who maintain that after few weeks of taking high enough doses of Ashwagandha and Rhodiola they managed to improve their mental health and slept much better. 

Ashwagandha increases athletic endurance, muscle mass, muscle strength & regeneration. 57 resistance trainers were given either a placebo or 300mg of Ashwagandha extract twice a day for 2 months. As a result, muscle strength & endurance improved in the Ashwagandha group by 30 to 50%; Arm muscles were 5cm larger in the placebo group and 9cm larger in Ashwagandha group; Chest muscles were 1.5cm larger in the placebo group and 3.5cm larger in Ashwagandha group. Ashwagandha also improved muscle recovery time & reduced muscle damage, significantly increased testosterone levels compared to placebo group, and produced significantly greater loss of body fat (23,24,25). 

In another study Ashwagandha doubled the swimming performance in rats and prevented decrease of adrenal cortisol & vitamin C (which occur due to swimming stress) (9). 

Proper cognitive function of the brain, focus and response time are also important aspects of athletic and sport performance. In one controlled study, healthy men on a daily dose of 500mg of standardized Ashwagandha extract experienced significant improvement in their reaction time and task performance (12). According to a 2-month study 50 adult subjects on 300mg of Ashwagandha root extract twice daily significantly improved general memory, task performance and attention (13). 


Immune System 

Studies have demonstrated that Ashwagandha stimulates the activity of natural killer cells, of the immune system that fight cancer cells and viral infections (26,27). It also strengthens immune system by increasing immunoglobulin production. 

Mice on Ashwagandha extract restored normal phagocytosis and had increased production of interleukin-2 and interferon-gamma, two important cytokines involved in immune function (28). 

Ashwagandha prevents cancer by increasing apoptosis (29), reducing prolactin (excess prolactin increases breast cancer risk) & reducing oestrogen in breast cancer cells (but not in healthy cells). 

Withaferin-A, a compound found within Ashwagandha, exhibits in vivo anticancer activity in human breast cancer cells (30). 

Ashwagandha has an antiproliferative effect against human breast cancer cells (31). 

Animal studies gave evidence that Ashwagandha may help cope with several types of cancer, including ovarian, breast, lung, colon, and brain cancer (32,33,34,35,36) 

Ashwagandha has pronounced and diverse anti-cancer activity (37). 

For instance, mice with ovarian cancer treated with Ashwagandha alone or Ashwagandha combined with an anti-cancer drug had a 70–80% reduction in tumour growth. Study results also claimed that the treatment prevented the spread of cancer cells to other organs (36). 

Ashwagandha selectively kills cancer cells (38). 

It is believed Ashwagandha has anticancer properties also due to its ability to generate reactive oxygen species (ROS), which are deadly only to cancer cells but not healthy cells. 

Ashwagandha helps prevent and treat cancer because it can be effective in fighting cancer-inducing free radicals. For instance, animals with liver and skin cancer treated with Ashwagandha had increased levels of glutathione, superoxide dismutase and catalase in the liver and skin (1,2). 

A water extract of Withania somnifera has potent cytotoxic effect on human malignant melanoma cells (39). 

Ashwagandha induces programmed cell death in human leukaemia cells (40). 


Blood Glucose 

Ashwagandha lowers increased blood sugar levels and improves insulin sensitivity (41). 

According to the results of a small study, participants with type 2 diabetes who were taking Ashwagandha for 30 days managed to lower fasting blood sugar levels as effectively as diabetes medication (42). 

Ashwagandha significantly improves insulin sensitivity in Non-Insulin Dependent Diabetes Mellitus (43). 


Appetite and Weight Control 

Ashwagandha root extract can be beneficial in body weight management. According to one study 600 mg of the herb per day reduced food cravings, reactive eating & body weight (44). 


Cholesterol and Triglycerides  

Ashwagandha helps lower LDL cholesterol & triglycerides while increasing HDL cholesterol in humans (3,6,23,42,45). 

In a 60-day trial with chronically stressed participants, those on the highest dosage of standardized Ashwagandha extract had a 17% decrease in “bad” LDL cholesterol and an 11% decrease in triglycerides (3). 

It lowered total cholesterol by as much as 53% and triglycerides by 45% in rats (46). 




Ashwagandha has shown to decrease inflammation markers, including C-reactive protein (CRP) which is also linked to an increased risk of heart attack. In one study, subjects who took 250 mg of standardized ashwagandha extract daily had a 36% decrease in CRP (3). 


Withdrawal Symptoms 

Ashwagandha attenuates withdrawal-induced anxiety due to chronic ethanol consumption (47). 

Withinia Somnifera alone and in combination with Shilajeet prevented ethanol withdrawal and alcohol addiction (48). 




  • Ashwagandha extract should be from root (highest source of key active ingredients). 
  • Should be standardised to give at least 5mg of Withanolides (most important active ingredients) per capsule/tablet (equivalent to about 5000mg of fresh Ashwagandha). 
  • Extract should be combined with Organic Ashwagandha Root Powder to make it holistic and more bioavailable. 
  • Should be fortified with antioxidant such as natural Vitamin E to prevent oxidation & preserve potency of Ashwagandha. 



1,250mg/day was safe in a study with 18 people. 

Ashwagandha has broad therapeutic value, with no known toxicity (49). 



1-2 times a day: 300-700mg of standardised extract. 

As always, it is better to start from smaller dosages and gradually increase. 

Use Ashwagandha alternatively with other excellent adaptogens and energy boosters such as Rhodiola, etc. 



Ashwagandha is not recommended during pregnancy as large doses may possibly increase risk of abortion. 

Since Ashwagandha acts as a mild anti-depressant, it shouldn’t be taken with alcohol, anti-anxiety & anti-depressant drugs. 

Individuals with hyperthyroidism should consult their practitioner before taking Ashwagandha. 

Ashwagandha may not be recommended in hirsutism (abnormal/excessive facial hair in women often associated with PCOS). 



Do not eat Ashwagandha berries, as they can cause severe gastrointestinal pain. 


Related Articles 



  1.  Effect of Withania somnifera on DMBA induced carcinogenesis. - Abstract - Europe PMC 
  2. Roots of Withania somnifera Inhibit Forestomach and Skin Carcinogenesis in Mice - PMC ( 
  3. withania_review.pdf ( 
  4. 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 - PubMed ( 
  5. Withania somnifera Improves Semen Quality in Stress-Related Male Fertility - PubMed ( 
  6. (PDF) A Standardized Withania Somnifera Extract Significantly Reduces Stress-Related Parameters in Chronically Stressed Humans: A Double-Blind, Randomized, Placebo-Controlled Study ( 
  7. A double-blind, placebo-controlled evaluation of the anxiolytic efficacy ff an ethanolic extract of withania somnifera - PubMed ( 
  8. Efficacy of Ashwagandha (Withania somnifera Dunal. Linn.) in the management of psychogenic erectile dysfunction - PubMed ( 
  9. An Overview on Ashwagandha: A Rasayana (Rejuvenator) of Ayurveda - PMC ( 
  11. Naturopathic Care for Anxiety: A Randomized Controlled Trial ISRCTN78958974 | PLOS ONE 
  12. Effect of standardized aqueous extract of Withania somnifera on tests of cognitive and psychomotor performance in healthy human participants - PubMed ( 
  13. Efficacy and Safety of Ashwagandha (Withania somnifera (L.) Dunal) Root Extract in Improving Memory and Cognitive Functions - PubMed ( 
  14. Water extract from the leaves of Withania somnifera protect RA differentiated C6 and IMR-32 cells against glutamate-induced excitotoxicity - PubMed ( 
  15. Possible neuroprotective effect of Withania somnifera root extract against 3-nitropropionic acid-induced behavioral, biochemical, and mitochondrial dysfunction in an animal model of Huntington's disease - PubMed ( 
  16. Withania somnifera improves semen quality by regulating reproductive hormone levels and oxidative stress in seminal plasma of infertile males - PubMed ( 
  17. Withania somnifera improves semen quality by combating oxidative stress and cell death and improving essential metal concentrations - PubMed ( 
  18. Efficacy and Safety of Ashwagandha (Withania somnifera) Root Extract in Improving Sexual Function in Women: A Pilot Study - PubMed ( 
  19. Clinical evaluation of Ashokarishta, Ashwagandha Churna and Praval Pishti in the management of menopausal syndrome - PubMed ( 
  20. Amelioration of metformin-induced hypothyroidism by Withania somnifera and Bauhinia purpurea extracts in Type 2 diabetic mice - PubMed ( 
  21. Efficacy and Safety of Ashwagandha Root Extract in Subclinical Hypothyroid Patients: A Double-Blind, Randomized Placebo-Controlled Trial - PubMed ( 
  22. Subtle changes in thyroid indices during a placebo-controlled study of an extract of Withania somnifera in persons with bipolar disorder - PubMed ( 
  23. Exploratory study to evaluate tolerability, safety, and activity of Ashwagandha (Withania somnifera) in healthy volunteers - PubMed ( 
  24. Examining the effect of Withania somnifera supplementation on muscle strength and recovery: a randomized controlled trial - PubMed ( 
  25. Effects of Withania somnifera (Ashwagandha) and Terminalia arjuna (Arjuna) on physical performance and cardiorespiratory endurance in healthy young adults - PubMed ( 
  26. In vivo enhancement of natural killer cell activity through tea fortified with Ayurvedic herbs - PubMed ( 
  27. In vivo effects of Ashwagandha (Withania somnifera) extract on the activation of lymphocytes - PubMed ( 
  28. Immune enhancing effects of WB365, a novel combination of Ashwagandha (Withania somnifera) and Maitake (Grifola frondosa) extracts - PMC ( 
  29. Molecular targets and mechanisms of cancer prevention and treatment by withaferin a, a naturally occurring steroidal lactone - PubMed ( 
  30. Withaferin A causes FOXO3a- and Bim-dependent apoptosis and inhibits ( 
  31. Ayurvedic medicine constituent withaferin a causes G2 and M phase ( 
  32. Effect of Withania somnifera root extract on spontaneous estrogen receptor-negative mammary cancer in MMTV/Neu mice - PubMed ( 
  33. Stabilization of membrane bound enzyme profiles and lipid peroxidation by Withania somnifera along with paclitaxel on benzo(a)pyrene induced experimental lung cancer - PubMed ( 
  34. Immunomodulatory effects of Withania somnifera on azoxymethane induced experimental colon cancer in mice - PubMed ( 
  35. AshwaMAX and Withaferin A inhibits gliomas in cellular and murine orthotopic models - PubMed ( 
  36. Withaferin a alone and in combination with cisplatin suppresses growth and metastasis of ovarian cancer by targeting putative cancer stem cells - PubMed ( 
  37. Selective killing of cancer cells by leaf extract of Ashwagandha: ( 
  38. Selective killing of cancer cells by Ashwagandha leaf extract and its ( 
  39. Withania somnifera Root Extract Has Potent Cytotoxic Effect against ( 
  40. Induction of apoptosis by withaferin A in human leukemia U937 cells ( 
  41. Hypoglycemic activity of withanolides and elicitated Withania somnifera - PubMed ( 
  42. Hypoglycemic, diuretic and hypocholesterolemic effect of winter cherry (Withania somnifera, Dunal) root - PubMed ( 
  43. Effect of Withania somnifera on insulin sensitivity in ( 
  44. Body Weight Management in Adults Under Chronic Stress Through Treatment With Ashwagandha Root Extract - PMC ( 
  45. Effects of Withania somnifera in patients of schizophrenia: A randomized, double blind, placebo controlled pilot trial study - PMC ( 
  46. Hypocholesteremic and antioxidant effects of Withania somnifera (Dunal) in hypercholesteremic rats - PubMed ( 
  47. Effect of Withania somnifera Dunal in ethanol-induced anxiolysis and ( 
  48. Effect of Withinia Somnifera and Shilajit on Alcohol Addiction in ( 
  49. Scientific basis for the therapeutic use of Withania somnifera ( 



  • Baitharu I, Jain V, Deep SN, Hota KB, Hota SK, Prasad D, Ilavazhagan G. Withania somnifera root extract ameliorates hypobaric hypoxia induced memory impairment in rats. J Ethnopharmacol. 2013 Jan 30;145(2):431-41. 
  • Li W, Zhao Y. Withaferin A suppresses tumour promoter 12-O-tetradecanoylphorbol 13-acetate-induced decreases in isocitrate dehydrogenase 1 activity and mitochondrial function in skin epidermal JB6 cells. Cancer Sci. 2012 Oct 27. 
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