Updated: May 8
Withania somnifera also known as Ashwagandha, Indian ginseng, Winter cherry, or Kaknaje Hindi, is a medicinal plant with a long history of traditional use in Ayurvedic practice and ancient medicine. Historically, WS has been used in the treatment of infertility, impotence, erectile dysfunction, joint pains and mood problems. The plant commonly grows in drier climates of the southern Mediterranean, Egypt, Morocco, Canary Islands, India, Iran, Jordan and other regions of the Middle East. Many different parts of the plant have been used in traditional medicine. In research, the most commonly used part was the root.
Scientific research has isolated several therapeutic components out of which the most effective appears to be Withaferin A and Wishanoside IV. Of course in herbal medicine the full herb is always better than the sum of its parts and any herbalist will tell you that herbs should not be extracted and micro-dosed but rather used cumulatively based on many specific factors determining the constitution of the patient. I agree with this argument. At the same time, it makes sense to understand how those herbs work in the basic biochemistry so that they can become of interest in pharmacological research and potentially we can get more research into natural compounds such as WS with more funding. More research also means more publicity and more public interest in these compounds which is always a good thing.
From this point onwards, I will refer to Aswagandha as WS
In this article, we will take a look at the effects of cognitive performance and mental health. In part 2, I would will review some of the exciting effects on male fertility, testosterone, DHEA and exercise performance. So without further ado, let’s just get straight into it
What are Adaptogens
WS is a member of the family of herbs referred to as “adaptogens”. This term is applied to a herb with phytonutrients that regulate metabolism when a body is burdened by physical or mental stress and adaptogens help to normalise and rebalance our natural stress responses to bring the body back into homeostasis. On a more biochemical level, this means adaptogens have a way to normalise secretions of particular hormones such as cortisol or DHEA that can be out of balance in periods of prolonged stress and this makes them beneficial for the health of our brain and nervous system as well as adrenal glands. Other examples of herbal adaptogens are Rhodiola, schizandra, ginseng, maca or skullcap.
Cognitive Function & Brain Performance
Many developed countries are experiencing a rapidly “greying” population, and cognitive decline is common in the elderly. There is no cure for dementia, and pharmacotherapy options to treat cognitive dysfunction provide limited symptomatic improvements.
In the UK alone 209,600 people are diagnosed with dementia each year. Globally it is 9.9 million each year, one person every 3 seconds. Most of these people get worse each year due to the lack of available treatments. And so many research trials are looking at various herbs and natural products to see if there are any benefits to be gained out there. The problem as always is lack of funding however we do have a few promising trials on the effects of WS in cognitive performance.
A few trials have looked at WS use in people with mild cognitive impairment (MCI) or dementia.
In a small study of 59 participants taking WS extract (250mg twice/day) for 8 weeks produced a cognitive improvement in patients with bipolar disorder
Similar results were produced in two other small studies (n=19 & n=59) on children with medically diagnosed mental retardation
In a study on 20 healthy male volunteers, significant improvements in reaction times, choice discrimination, digit vigilance, and card sorting tests were seen at 250mg/day for 14 days.
And finally a study on 50 people with mild cognitive impairment (>35 years old) has also shown significant improvement to their overall cognitive performance after taking 300mg WS extract twice a day for 8 weeks.
And while the majority of these trials were either on people with an already ongoing disability (such as mental retardation or diagnosed cognitive impairment) and not on healthy young individuals, it appears WS extract at somewhere between 300-600mg a day may be useful. Ideally, we would have more extensive studies with more participants that would last for a few years but creating such trials is incredibly expensive, and herbal trials are notoriously underfunded (lack of interest from big pharma), and so we have to rely on the small data we have.
It is not yet clear how the herb works and what is the mechanism through which it improves cognitive performance; however, some in-vitro studies have shown that WS may increase levels of BDNF, an important neurotrophic factor in the brain (I have full blog post on BDNF is this topic interests you). A study on rats has found that WS extract stimulates neuroplasticity in the brain, an essential process for the formation of new memories, knowledge and uptake of new information. Other in-vitro studies have shown anti-inflammatory function, and so the effect could be down to being able to attenuate inflammation in the brain, which is a common occurrence in people with dementia and mild cognitive impairment.
In summary, WS may be a fairly effective alternative choice for people wild mild cognitive impairment who do not want to take or can’t tolerate medication. For people already on medication, the addition of WS may be helpful; however, it should first be discussed with and approved by their doctor.
For young, healthy individuals who are looking to try something new, a 300mg WS root extract taken twice a day may be worth the experiment as there were no reported adverse effects.
Aswagandha (WS) & Mental Health
A small study on 66 schizophrenic patients suffering from anxiety and depression found that those taking WS extract for 12 weeks had improvement on their mood scale, and their anxieties and depression both have improved significantly.
Another 60-day study on 67 participants receiving either placebo or WS found the following:
Reduced fasting cortisol (major stress hormone) in WS group
Greatly improved mood and reduced self-perceived levels of depression & anxiety
Mild improvement of DHEA (an important sex hormone that is often disrupted in chronic stress)
Improved levels of testosterone (results did not, however, reach statistical significance – possibly due to small study size)
How does Aswagandha (WS) work? [for the nerds]
WS appears to attenuate the function of what we call HPA-Axis. HPA-Axis is the human stress-response system. When a stressor emerges, the brain region called the hypothalamus (H) sends a signal to a pituitary gland (P) to send a signal to adrenal glands (A) to release adrenaline, noradrenaline and cortisol, our 3 major stress hormones. (see the image below describing the process) The function of these is to support survival in a stressful situation and to induce adaptation, and prevent panic attacks and loss of rational thinking. These hormones also cause an increase in heartbeat, an increase of breathing rate, dilation of the eye, the tension in the muscles and release of glucose into the circulation – basically, the body is getting ready to kill or to run away from the wild animal (HPA-Axis is a primitive ancient survival mechanism). While HPA-Axis is designed to protect us, overexposure to these stress hormones may lead to anxieties, panic attacks or depression, even to gradual burn-out of the body.
source: Andro Health Nutrition
WS appears to be able to normalise the excessive activity of HPA-Axis by balancing the hormones produced by adrenal glands and by the hypothalamus. Human studies showed reduced levels of cortisol in the morning after taking WS extract for several weeks. Additionally, it has been found (in-vitro) that WS can support the function of a neurotransmitter called GABA that induces a feeling of peace and relaxation through stimulating GABA-receptors; however, this mechanism is difficult to assess in human studies, so for now, it remains mostly speculation.
Only a single study has been done on WS in patients with insomnia (another one is in progress), and it showed that both healthy volunteers and those with insomnia benefited significantly from taking 300mg extract of WS twice a day. Their sleep has improved significantly. It took the participants less time to fall asleep, their sleep was deeper and less disturbed. And while we need more data to confirm the results, it is safe to say that WS may be worth trying for those who suffer from disturbed sleep and for whom other remedies have not been effective.
Summary & Key Points
Human studies on Aswagandha (Withania Somnifera / WS) show multiple health benefits across different health conditions. WS is an adaptogen which means it can help normalise the human stress response axis (HPA-axis) by reducing secretions of particular stress hormones in the blood.
Mental Health –A small number of studies have shown promising effects for anxiety, depression and mood disorders. Doses from 300-600mg per day have commonly been used and were deemed safe to take. Patients taking WS report feeling better, happier and less anxious and less worried.
Cognitive performance – in people with mental disability and medically diagnosed mild cognitive impairment (MCI is a pre-step to dementia) WS extract has been helpful in improving overall cognitive performance. In a study on 20 healthy male volunteers, significant improvements in reaction times, choice discrimination, digit vigilance, and card sorting tests were seen. WS extract may be useful for those wishing to experiment with natural brain-enhancing supplements that are safe and non-toxic; however, larger studies are missing to confirm or reject whether the herb really works.
Insomnia – Only single study has looked at the effects of WS on people with insomnia and it found that those taking WS extract (300mg twice a day) had better sleep quality, deeper sleep, and it took less time to fall asleep.
Safety & Dosage – WS (Aswagandha) extract up to 1000mg per day in split doses was well tolerated and safe to take. According to WebMD, people taking medication for blood sugar, depression, anxieties, heart medication, blood thinners, thyroid medication, blood pressure meds or immune suppressants should first discuss supplementation with ashwagandha with their doctors.
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Abhijit, D. Irani, N. Balakrishnan, R. (2018). ‘Study protocol and rationale for a prospective, randomised, double-blind, placebo-controlled study to evaluate the effects of Ashwagandha (Withania somnifera) extract on nonrestorative sleep’, Medicine, 97 (26).
Gannon, J. M. et al. (2019) ‘Effects of a standardised extract of withania somnifera (ashwagandha) on depression and anxiety symptoms in persons with schizophrenia participating in a randomised, placebo-controlled clinical trial’, Annals of Clinical Psychiatry, 31(2), pp. 123–129.
Langade, D. et al. (2021) ‘Clinical evaluation of the pharmacological impact of ashwagandha root extract on sleep in healthy volunteers and insomnia patients: A double-blind, randomised, parallel-group, placebo-controlled study’, Journal of Ethnopharmacology. Elsevier B.V.
Ng, Q. X. et al. (2020) ‘A systematic review of the clinical use of Withania somnifera (Ashwagandha) to ameliorate cognitive dysfunction’, Phytotherapy Research, 34(3), pp. 583–590.
Pratte, M. A. et al. (2014) ‘An alternative treatment for anxiety: A systematic review of human trial results reported for the Ayurvedic Herb Ashwagandha (Withania somnifera)’, Journal of Alternative and Complementary Medicine, 20(12), pp. 901–908.