One of my biggest concerns about modern medicine is our increasing “medicalization of human despair.” Life can be stressful and many people live with what is called a “high allostatic load.” Something trivial (or big) can be the tipping point.

These people often present to the doctor with a myriad of complaints: fatigue, insomnia, anxiety, poor concentration. Time constraints, decision fatigue and lack of training on behalf of the physician can result in a prescription for sleeping tablets, anti-anxiety pills, anti-ulcer pills, antidepressants, or pain killers.

I often think that these people need a good tonic (to paraphrase my Irish grandmother). Something to build them up and help them find their mojo. Western medicine fails spectacularly here.

The most likely candidates for this role are adaptogens. Adaptogens come from Ayurvedic medicine (traditional Indian medicine) and help people withstand the trials of daily life.

What is Ashwagandha?

Withania somnifera is also known as ashwagandha, winter cherry, horse smell and Kaknaje Hindi (1). It is also called Indian ginseng but it has nothing to do with ginseng from a botanical point of view. It is actually a member of the Solanaceae family of plants (just in case you get called to appear on a quiz show on TV and your specialist topic is plants).

The term “Withania somnifera” roughly translates to sleep-inducing. It grows well in warm arid climates especially India, Yemen, and parts of the USA.

It is a small shrub that has leaves, roots and red berry fruits.

The roots of the plant have been used in the Ayurvedic or traditional Indian medicine for 6000 years. Ayurveda dates back to at least 1500 BC. The word Ayurveda is a Sanskrit word that translates into ‘science of life’ or ‘knowledge of life’.

It is a holistic healing system that is designed to promote good health and longevity rather than curing particular diseases. According to Ayurveda, all objects and living bodies are composed of 5 basic elements; fire, water, earth, air, and vacuum.

Ashwagandha is considered to be a cornerstone of Ayurvedic medicine and is part of over 200 Ayurvedic remedies. Ashwagandha is classified as an adaptogen and a “rasayana” plant or rejuvenator. It is also called a “medharasayana” meaning that it really helps with brain rejuvenation. It is known as the Queen of Ayurvedic medicine (aka the big kahuna).

The plant contains over 80 phytochemicals including steroidal alkaloids, non-steroidal alkaloids, steroidal lactones, saponins, amino acids (aspartic acid, glycine tryptophan, proline, alanine, and valine), calcium, phosphorus, iron, flavonoids, starch, reducing sugars and volatile oils.

There are four main formulations of ashwagandha and I tried out all four while preparing this article.

1. Loose Powder

This is my absolute favorite. It is really versatile and can be added to chai, smoothies, salads, and oatmeal.

2. Capsules

These are great for travel. After all, who wants to explain to the humorless folk at the X-ray screening in the airport that the odd-looking powder is medicinal. They will take one look at your new-found adaptogenic, zen-like state and immediately detain you!

3. Tincture

I don’t really care for the tincture. There is something about the taste and texture. It is very heavy – according to me. Depending on what you read, ashwagandha either means “smells like a horse” or “gives the power of a horse.” 

I think that the tincture probably smells and tastes of a horse! Not that I really know what tasting like a horse would be. I also suspect that long term use could stain teeth. But you can try for yourself.

4. Mixed With Ghee

I like cooking with ghee sometimes. But I really don’t care for the taste of ashwagandha and ghee. It is really sticky and tastes odd – again in my opinion.

Ashwagandha is popular. India alone produces 1500 tonnes of the plants per year and people use about 7000 tonnes of the plant per year worldwide.

It is used for: fatigue, arthritis, anxiety, depression, Parkinson’s disease, Alzheimer’s disease, Huntington’s chorea, obsessive-compulsive disorders, ADHD, diabetes, lipid control, stress, memory, skin disorders, infections, libido, fertility, anti-aging, vitality and sleep (2). So pretty much the Swiss army knife of adaptogens.

Ashwagandha may be popular but it could hardly be said to be “trending. The #ashwaganda is tagged 6345 times on Instagram, #adaptogen 10,000 times while #tired gets tagged 24,000,000 times.

Is There any Research?

There are over 1000 articles on ashwagandha which includes just 23 clinical trials. To put this into context, there are 815 publications on rhodiola (another popular adaptogen) which includes 45 clinical trials. 

Does Ashwagandha Boost Thyroid Function?

As early as 1998, studies in mice suggested that ashwagandha can help stimulate thyroid function  (3, 4).

Safety monitoring in a study of ashwagandha in patients with bipolar disease revealed subtle increases in thyroid hormone levels (5).

A study from Varansai published just this year looked at the efficacy and safety of ashwagandha root extract in subclinical hypothyroidism (6). The study was a prospective double-blind, placebo controlled trial. The study enrolled a total of 50 adults who participated in an 8-week treatment program.

The ashwagandha was given at a dose of 600 mg. The study found a statistically significant improvement in thyroid stimulating hormone (TSH), T4 and T3 in the study participants. Overall the ashwagandha was well tolerated.

Care should be taken with ashwagandha as a case of clinical thyrotoxicosis (hyperthyroidism) was reported in a 32-year-old healthy lady who took ashwagandha. (7).

Bottom Line

There is evidence that ashwagandha can boost thyroid function. As the thyroid is a very important hormone-producing gland that regulates many critical physiological processes, it must be emphasized that using ashwagandha as an DIY attempt to manipulate thyroid function would be ill-advised.

Does it Improve Depression, Anxiety and Stress?

A review of herbal medicines for psychiatric disorders published in Phytotherapy Research last year found preliminary evidence that Withainia can help with mood disorders (8). Let’s take a closer look at the data for ourselves as this is a really important topic.

The combination of Bramhi (Bacopa monnieri) plus Withania along with the antidepressant, imipramine, showed significant anti-depressant effects in albino rats (9).

In another study, the stress-relieving and mood-stabilizing effects of Withania were compared head to head with the benzodiazepine, lorazepam, and the tricyclic antidepressant, imipramine, in rats (10).

Withania was found to be as effective an anxiolytic (anxiety reliever) as lorazepam and as effective an antidepressant as imipramine.

How on earth can you tell that your rat is feeling blue? Rat researchers use metrics such as eating habits, social interactions and levels of chemicals in the brain to asses the mood of rats..

A total of 64 adults with a history of chronic stress were randomized to either Withania 300 mg twice daily or placebo for 60 days (11). Using validated questionnaires and serum cortisol levels, statistically significant improvements in stress levels were noted as compared to the control group.

A systematic review of Withania for anxiety and stress found just 5 eligible randomized controlled trials (12). The authors intended to do a meta-analysis but did not proceed with this due to the very small number of studies.

They had expected to find more studies but decided to eliminate studies that used  Ayurvedic as opposed to western disease classifications.

Four of the studies showed significant benefits in favor of Withania over placebo. The fifth study showed a benefit but this did not reach the level of statistical significance. The reviewers noted that this study had the smallest sample size and shortest duration.

A really interesting study found that the combination of Withania plus intermittent fasting reduced anxiety-like behavior and associated neuroinflammation in middle aged rats (13).

Bottom Line

I agree with the conclusion of last years review that there is preliminary evidence that ashwagandha can help with mood disorders but larger, higher-quality trials are needed to verify these findings.

Does it Help With Weight?

A 2017 study from India looked at the effect of Withania on body weight in adults under stress (14). Chronic stress can affect weight through 3 key mechanisms:

  • increased food intake
  • cravings for sweet and fried foods and/or
  • reduced exercise.

The study enrolled 52 subjects who were diagnosed with chronic stress. The study subjects were randomized to either Withania 300 mg twice daily or a matched placebo twice daily for 8 weeks.

The placebo resembled the active pill in size, shape, and color. Statistically significant improvements were noted in perceived stress, food cravings, serum cortisol, and body weight. On closer inspection, significant reductions in body weight were noted in both groups at 8 weeks (3.03% for the treatment arm versus 1.46% for the placebo).

The mean reduction in BMI from baseline was 2.93% in the treatment group which was statistically significant as compared to a 1.4% reduction in the placebo arm.

 The Withania was well tolerated. The only side effects noted were mild and included giddiness, heaviness of the head and blurred vision.

Bottom Line

Again, there is a low amount of preliminary evidence that Withania may help with weight loss.

Does it Protect Brain Cells & Improve Memory?

A key tenet of Ayurvedic medicine is establishing balance between the body, mind, and soul and it is believed that as such, ashwagandha has a scientific basis in the treatment of neurological and degenerative disorders (15).

We have one contemporary clinical trial to look at here.

An 8-week study comparing Withania 300 mg to placebo over 8 weeks in 50 adults with mild cognitive impairment found improvements in immediate and general memory as well as attention, and information processing speed (16).

Bottom Line

Yet again, dare I say, that there is preliminary evidence to support a role for ashwagandha for brain health.

Does it Help With Sleep?

Withania somnifera means sleep-inducing. I became very excited to see a 2018 publication on Withania and sleep. Unfortunately, it was only a placeholder. It tells us that there is a plan to do a 42-day study in 150 subjects(17). End of story.

Bottom Line

There is currently no scientific proof that Withania helps with sleep.

Does it Relieve Adrenal Fatigue?

The concept of adrenal fatigue is a western modern construct. Therefore, I don’t expect to see a large randomized controlled clinical trial on Withania in adrenal fatigue.

In general, I don’t like to extrapolate as it can be a slippery slope between extrapolation and making things up. However, I do think that the adaptogens may well have a role in adrenal fatigue. When we read about the common uses for adaptogens, it sounds very like the common presenting symptoms of adrenal fatigue.

Stress and raised cortisol are cardinal features of adrenal fatigue and we have seen that Withania has been shown to help with both of these features (11,14).

Bottom Line

There is no direct evidence that Withania can help with adrenal fatigue but it is biologically plausible and is well worth studying.

Does it Fight Cancer?

There is one clinical trial to look at here (18). This study did not look at cancer per se but looked at side effects of cancer such as fatigue and quality of life. Ashwagandha was tested in 100 women with breast cancer and was found to significantly help with fatigue and quality of life but not overall survival.

Beyond this one clinical study, we have a range of pre-clinical studies of interest.

Triethylene glycol was identified as a possible anticancer constituent of ashwagandha in a 2013 study from Japan (19).

Withaferin A from ashwagandha was also shown to inhibit B-cell lymphoma in a laboratory model (20).

Another study showed that it could help with programmed cell death in human head and neck cancer cell lines (21).

It also exhibited activity against certain brain cell tumors (known as gliomas) (22).

An emerging interesting twist on the possible role for ashwagandha in cancer relates to the concept of ‘priming’. In the context of cancer, this refers to using strategies to increase the efficacy of chemotherapy agents.

There is one study which showed that using ashwagandha before the chemotherapy agent, cisplatin, helped to increase the potency of this drug against colon cancer cells. No enhanced effect was noted in non-cancerous cells (23).

Bottom Line

Despite encouraging data from numerous pre-clinical studies, we have no data from clinical studies to guide us on the safety or efficacy of ashwagandha for cancer.

Does it Help Control Diabetes?

We know from a Cochrane review that Ayurvedic treatments (with or without oral hypoglycemic agents or insulin) can significantly reduce HBA1C (a long term marker of blood glucose control) (24).

The datasets were small and subgroup analysis could not be performed which makes it impossible to comment on ashwagandha.

Six subjects with non-insulin dependent diabetes were treated with Withania 300 mg for 30 days (25). They found significant decreases in blood glucose (and cholesterol) which was comparable to the glucose-lowering effects of oral hypoglycemic agents.

In a very recent study, Withania extract reduced blood sugar and the rate of new diagnosis of diabetes in rats that had been treated with streptozotocin (26). The streptozotocin is used to induce poor glucose control and diabetes.

Bottom Line

There is some very limited data to suggest that Withania may help with blood glucose control. However, this is really just pilot data and should absolutely not be used instead of standard treatments for diabetes.

Does it Boost Immunity?

Immunity and inflammation are closely related. Inflammation is one of the beneficial effects of immunity. It was first described by Cornelius Celsus in the first century and the full clinical significance of inflammation was later recognized in the nineteenth century by Rudolf Virchow (27).

Like everything in life, it is all a question of moderation. Some inflammation can be helpful. Excessive inflammation puts us at risk of chronic lifestyle diseases eg diabetes, Alzheimer’s, cancer and heart disease. Nuclear Factor-kappaB (NF-KB) is a key molecule that mediates inflammation in the body.

Researchers at MD Anderson carried out an interesting study and used a “bedside to bench” approach. The interesting part about this is the fact that the vast majority of research is “bench to bedside.” These researchers decided to flip this around in what they called “reverse pharmacology.”

They started with the centuries of clinical experience with Ayurvedic medicines and then went to the bench to see if there was any science to support clinical use of a wide range of Ayurvedic medicines including ashwagandha.

The researchers identified a number of animal studies which showed that the witahanolides from ashwagandha suppressed NF-kB activation.

As seen above, there is clinical evidence which shows that Withania can lower cortisol levels.

Bottom Line

There is very limited evidence to suggest that Withania can modulate immunity and inflammation. As we have discussed in previous articles, the immune system is really complex and it is impossible to say if an isolated increase or decrease in any one molecule would be beneficial or detrimental for any individual patient.

Does it Improve Sexual Function and Fertility?

Ashwagandha is mentioned in the Kama Sutra. Need I say anymore? In the interests of science, I will elaborate.

There are two theories as to how ashwagandha might help with sexual function.

  • Firstly, it may act by lowering stress.
  • Secondly, it may act by regulating testosterone levels.

A study from India looked at the efficacy and safety of ashwagandha extract in improving sexual function in women (28). For this study, 50 women with hypoactive sexual desire, sexual arousal disorder, female orgasmic disorder were enrolled in the study.

In order to meet the entry requirements for the study, the women need to have a male partner who was not impotent and needed to agree to engage in sexual intercourse at least twice per week.

All in the name of research. The women were randomized to either placebo or ashwagandha 300mg for 8 weeks. The study found statistically significant improvements in arousal, lubrication, orgasm, and satisfaction. Oh, the sacrifices that people are willing to make for research.

In another study, a total of 46 men with oligospermia (sperm count < 20 million per ml) received either Withania  675 mg daily or placebo for 90 days (29). A total of 46 men with oligospermia (sperm count < 20 million per ml) received either Withania 675 mg daily or placebo for 90 days.

The treatment arm of the study had a 167% increase in sperm count, a 53% increase in semen volume and 57% increase in sperm motility from baseline. All of these improvements were statistically significant. The improvement in these parameters was minimal in the placebo-treated group.

 A 2010 study in 75 fertile men and 75 men undergoing fertility treatment found that Withania could improve sperm count and motility (30). The treatment arm of the study had a 167% increase in sperm count, a 53% increase in semen volume and 57% increase in sperm motility from baseline. All of these improvements were statistically significant.

The improvement in these parameters was minimal in the placebo-treated group.

Finally, normozoospermic infertile men (don’t judge, that is an actual word and means normal sperm) were given 5gm of Withania per day (a mega-dose) and had improvements in their sperm and a 14% fertility rate (31).

Before you go out and buy a ton of ashwagandha, it is worth noting that a 2018 systematic review of the effects of ashwagandha on the reproductive system found benefits but also harms (32). They identified animal studies that showed spermicidal and infertilizing effects in male rats.

Bottom Line

There is evidence to support a possible role for ashwagandha in reproductive health but there is also some evidence of harm. As such it can not be recommended for the improvement of sexual function or fertility.

Does it Increase Muscle Mass, Strength, Stamina and Endurance.?

strengthA prospective, randomized,  double-blind study evaluated the effect of with Withania on cardiorespiratory endurance in 50 healthy adults (33). The treatment schedule involved Withania 300mg twice daily for 12 weeks in half of the study subjects, while the other half received a matched placebo.

The metrics used in the study were oxygen consumption at peak physical exertion during a 20m run and World Health Organization quality of life questionnaire. One subject withdrew from the study. Statistically significant improvements in both metrics were noted in this study.

An eight-week study which was published in the Journal of the International Society of Sports Nutrition shared very interesting data (34). This was a randomized controlled trial in 57 men with limited experience in resistance training. 

The study participants received either Withania 300 mg twice daily or a matched starch control. The main outcomes were muscle strength, muscle size, muscle recovery, and testosterone. Muscle strength was measured by using a bench press and leg extension. Muscle recovery was measured by creatine kinase blood levels. 

The ashwagandha arm had statistically significant increases in all key metrics including muscle strength, muscle size, muscle recovery, and testosterone.

Two things are noteworthy here.

Firstly, I don’t know what would happen with ashwagandha use in people who are already superfit with a 6 pack. As an adaptogen, ashwagandha is all about returning things to normal and helping people withstand stresses.

 Hence it fits with the raison d’être of ashwagandha to build muscle in people who start resistance training. I don’t know if ashwagandha is a “pimp up my ride” type of herb in people who might already be pushing physiological limits with their body habitus.

Secondly,  I don’t know what would happen if people would continue to add muscle if they take Withania for long periods of time.

Extracting data from a single-blinded study looking at Withania and/or Terminalia arjua in 40 adults over 8 weeks showed that Withania increases velocity, power and oxygen consumption (35). 

The researchers used kinematic measuring systems which consists of cameras placed at specific intervals to measure velocity when running, jumping and using a wobble board. No improvements in balance were noted for Withania.

In another study, Withania was dose titrated up to 1250mg/day for 10 days (36). Muscle strength was assessed by handgrip and quads strength. Exercise tolerance was measured by a cycle ergometer. The study found statistcally significant increase in strength. There was a non-significant increase in lean body weight. 

They also found a non statistically significant decrease in body weight. One volunteer was withdrawn from the study with complaints of an increased libido. I wonder how they classified this as a side effect?

Bottom Line

I do think that there is promising evidence that Withania can help with physical performance.

Is Ashwagandha Safe?

None of the studies that we have reviewed have flagged any safety concerns for Withania with the exception of the single case report of thyrotoxicosis (7).

An audit of adverse drug reactions in a secondary care Ayurvedic clinic in India revealed an extremely low rate of side effects (1.14%) and none appeared to be related to Withania (37).

In Ayurvedic medicine, Withania is not recommended in pregnant women due to a risk of miscarriage.

Withania contains fiber and it is generally advisable to drink extra water when supplementing with this plant.


Looking at the number of times the term ‘tired’ has been tagged on Instagram tells us that many people do indeed lead ‘lives of quiet desperation’. Ashwagandha may well hold the key to this type of existential angst for many people.

The problem is that we have little research to go on. I would love to see more research into adaptogens and particularly, ashwagandha.

That being said, a wise botanist once told me that there is no moral superiority in substituting herbs for pharmaceuticals. The real solution lies in eliminating the actual cause of the problems.

I totally agree. However, I think that many people are too caught up in their ‘lives of quiet desperation’ to be able to address the big picture. I think that if ashwagandha does what it is reported to do, that it could help people to find some temporary relief that would allow them to re-think their lives.

Problem is that some of the reputation of ashwagandha is hearsay at this stage. We really, really need more research here.

Was this page helpful?