In Ayurveda, the ashwagandha root was called „the smell of a horse” – from the scent of the raw material and the belief that it imparts the strength of the animal. Today ashwagandha features in clinical trials on cortisol, sleep and stress resilience. It has moved from the herbalist’s shelf to randomised, placebo-controlled studies at universities in India and Australia. Find out what the research really shows about ashwagandha, when this adaptogen makes sense and when it’s better to leave it on the shelf.
Key facts about ashwagandha:
- Ashwagandha is an adaptogen – a plant that helps the body cope with stress
- The main clinical trials focus on lowering cortisol, reducing anxiety and improving sleep quality
- Standardised extracts (such as KSM-66 and Sensoril) have the strongest evidence in the literature
- Effects appear gradually – most studies ran for eight to twelve weeks
- Not for everyone – caution is needed in thyroid and autoimmune conditions and during pregnancy
What is ashwagandha?
Ashwagandha (Withania somnifera) is a shrub from the nightshade family whose root has been used by Ayurvedic medicine for over two thousand years. In Indian tradition it is classified as a rasayana. A tonic that supports vitality and is thought to slow the ageing process. The medical world is paying closer attention to this plant.
The active compounds in ashwagandha are withanolides. A group of steroidal substances that modulate the stress axis. Concentration of withanolides varies between parts of the plant and methods of extraction. Standardised root extracts state a specific withanolide content on the label, which makes it easier to compare them with the clinical trials.
What are adaptogens?
Adaptogens are plants that help the body adapt to stress. Without stimulating it like caffeine and without sedating it like tranquillisers. The term was coined in 1947 by the pharmacologist Nikolai Lazarev, who used it to describe substances that increase the body’s „non-specific resistance”. Apart from ashwagandha, the group includes rhodiola, maca root and eleuthero.
How does ashwagandha act on the body?
Ashwagandha works mainly through the hypothalamic-pituitary-adrenal axis, the system that regulates cortisol release and the stress response. Withanolides act on GABA receptors. GABA being the neurotransmitter responsible for calming the nervous system. Most studies measure effects in the context of chronic stress, rather than in well-rested people.
The main directions of ashwagandha’s action in research:
- A reduction in cortisol levels in people with a heightened stress response
- Lower anxiety scores measured on standard clinical scales
- Better sleep quality – shorter time to fall asleep and fewer awakenings
- Support for physical performance in some trials with people who train
- Modulation of immune markers seen in selected studies
How does ashwagandha lower cortisol and stress levels?
Ashwagandha calms the hypothalamic-pituitary-adrenal axis and lowers cortisol release under chronic stress. The effect comes from withanolides that modulate GABA receptors. In a study by Chandrasekhar from 2012 (Indian Journal of Psychological Medicine) people taking the extract for sixty days had cortisol about 28 per cent lower than the placebo group.
What is ashwagandha used for – what does the research show?
The strongest evidence concerns stress, anxiety and sleep disturbances. Topics that have been studied closely over the last decade. Weaker, though promising, are findings on libido and performance markers. Chronic stress leaves traces throughout the body, so a plant which lowers cortisol attracts the interest of clinicians.
A study by Lopresti from 2019 in Medicine (Baltimore) confirmed those results. KSM-66 participants had lower morning cortisol and lower anxiety scores. The question of what ashwagandha gives men comes up often. Trials suggest modest support for performance and libido markers. If you’re considering ashwagandha, introduce alongside it ten minutes of daily meditation.
What do clinical trials say about ashwagandha dosing?
In most randomised trials a safe ashwagandha dose sat in the range of 300 to 600 mg per day of a standardised extract, split into two portions. Such a daily ashwagandha dose gives stable withanolide levels. Higher doses – up to 1200 mg – have been tested less often and without a clear advantage.
Studies are not a recommendation for an individual. Every extract differs in its standardisation. 300 mg of KSM-66 is a different concentration of withanolides than 300 mg of cheap powder from an unknown source. The topic of ashwagandha and the thyroid calls for a separate conversation with an endocrinologist, since the plant can modulate thyroid hormone levels. Any decision is best discussed with a treating doctor.
How long does it take for ashwagandha to start working?
The first noticeable effects usually appear between the second and fourth week of regular use, while fuller changes in clinical studies were measured after eight to twelve weeks. That’s how an adaptogen differs from an anti-anxiety drug. There is no immediate calming after a single dose.
The typical course of effects in studies:
- Weeks 2-4 – the first signals: calmer sleep and less irritability in the evening
- Weeks 4-8 – clearer reduction of tension on clinical scales
- Weeks 8-12 – measurable cortisol changes and a fuller adaptogenic effect
Subjectively, people most often notice calmer sleep first. Only later comes greater resilience to everyday challenges. If after twelve weeks no change is visible, ashwagandha is unlikely to work in this case.
Ashwagandha – facts and myths
A fair number of myths have grown up around ashwagandha. From testosterone boosting to a quick lift in mood from the very first dose. Research shows effects mainly in the area of stress and sleep, after weeks of use. Not every ashwagandha is the same. Standardisation and the part of the plant matter. The plant does not replace therapy for mental disorders and has real contraindications.
The text above is for educational purposes and does not replace medical advice. Before starting supplementation. Especially with thyroid or autoimmune conditions, during pregnancy or while on pharmacotherapy – consult your treating doctor.
FAQ: Frequently asked questions about ashwagandha
When should ashwagandha be taken – in the morning or in the evening?
The timing depends on the goal and individual response – people with sleep problems often choose an evening dose, while those looking for stress support split the portion into a morning and an evening one in line with the clinical trial protocols.
What are the side effects of ashwagandha?
The most commonly reported are gastrointestinal complaints, drowsiness, headaches and occasional effects on thyroid results; isolated cases of liver injury have also been described, so longer use calls for periodic monitoring.
Is ashwagandha safe long-term?
Most clinical trials lasted from eight to twelve weeks, so the data on multi-year safety are limited and point to the need for periodic breaks and monitoring of liver and thyroid function.
Which ashwagandha is the best?
The best researched are standardised root extracts with a defined withanolide content (such as KSM-66 or Sensoril), since these are the ones used in clinical trials – cheap, unstandardised powders may contain minimal amounts of the active compounds.
References:
- Chandrasekhar, K., Kapoor, J., Anishetty, S. (2012). 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. Indian Journal of Psychological Medicine. https://doi.org/10.4103/0253-7176.106022
- Lopresti, A. L., Smith, S. J., Malvi, H., Kodgule, R. (2019). An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract. Medicine (Baltimore). https://doi.org/10.1097/MD.0000000000017186
- Salve, J., Pate, S., Debnath, K., Langade, D. (2019). Adaptogenic and Anxiolytic Effects of Ashwagandha Root Extract in Healthy Adults: A Double-blind, Randomized, Placebo-controlled Clinical Study. Cureus. https://doi.org/10.7759/cureus.6466
