Ashwagandha: Plant Profile, Traditional Use, and Modern Research
The 30-second answer
Ashwagandha (Withania somnifera) is a small shrub native to India whose root has been used in Ayurvedic medicine for over 3,000 years. It belongs to the Solanaceae (nightshade) family and is classified in Ayurveda as a Rasayana – a traditional rejuvenative herb. Modern research has investigated its effects on stress, sleep, anxiety, physical performance, cognition, and reproductive markers in over 20 small-scale randomised controlled trials. As a food supplement in the UK, it is regulated under food law, not as a medicine.
Key facts
- Plant family: Solanaceae (nightshade) – same family as tomatoes and potatoes
- Parts used: root primarily; occasionally leaves; rarely berries
- Active compounds: withanolides (steroidal lactones) – 40+ identified, withaferin A most studied
- Traditional context: Rasayana (rejuvenative), balya (strength-supporting), medhya (intellect-related)
- Doses studied: 240–600mg standardised root extract, daily, for 8–12 weeks
- Should not use: pregnancy, breastfeeding, autoimmune or thyroid conditions without GP guidance
What is ashwagandha?
If you’ve heard of one Ayurvedic herb, there’s a good chance this is it. Ashwagandha is a small, woody perennial shrub native to the dry regions of India, the Middle East, and parts of Africa. Its botanical name is Withania somnifera, and it belongs to the Solanaceae family – the nightshade family that also includes tomatoes, potatoes, and aubergines.
The plant typically grows 30 to 150 centimetres tall, produces small greenish-yellow flowers, and bears bright red-orange berries enclosed in a papery husk that resembles a Chinese lantern. That last feature is why ashwagandha is sometimes called “winter cherry” in English. The Sanskrit name itself translates roughly to “smell of the horse” – a reference to the earthy, slightly equine aroma of the dried roots.
Almost all clinical research uses root material only.
Which parts of the plant are used?
The root is the primary medicinal part. Yellowish-brown, finger-like, and 10–30 centimetres long when dried, the root contains the highest concentration of the plant’s active compounds and is the part used in almost all modern clinical research and most traditional Ayurvedic preparations.
The leaves are also used in some traditional formulations, particularly for topical applications. Their phytochemical profile differs from the root – they tend to contain more withaferin A but less of the broader spectrum of compounds present in roots. Most reputable supplement manufacturers use root-only or root-predominant material; cheaper products sometimes use leaf-and-stem material, which carries a different and less well-studied compound profile.
The berries are used occasionally in traditional preparations – and as a coagulant in some regional cheese-making traditions – but rarely appear in modern supplements.
Did you know?
The Sanskrit word ashwa means “horse”, and gandha means “smell.” Classical Ayurvedic texts considered the herb’s aroma so distinctive it became part of its name – and built a metaphor: those who took it were said to take on the strength of a horse.
Active compounds
The most studied compounds in ashwagandha are the withanolides – a family of naturally occurring steroidal lactones unique to Withania and a small number of related plants. The first, withaferin A, was isolated by Israeli chemist David Lavie and colleagues in 1965. More than 40 distinct withanolides have since been characterised. Other notable compounds include withanolide A, withanolide D, the sitoindosides VII–X, and a range of alkaloids including somniferine and isopelletierine.
Most standardised root extracts used in clinical trials are characterised by their total withanolide content, typically between 1.5% and 5% by weight. KSM-66, the extract used in the majority of high-quality recent trials, is standardised to a minimum of 5% withanolides and is produced from root material only.
3,000+
Years of use
40+
Compounds
20+
Clinical trials
A brief history of ashwagandha
Ashwagandha is one of the oldest documented medicinal plants in the world. Its journey from a desert-loving shrub to a globally researched supplement spans more than two millennia of continuous use.
c. 1000 BCE – 600 CE
Classical Ayurvedic period
The earliest written reference to ashwagandha appears in the Charaka Samhita, the foundational Ayurvedic text compiled in its current form between roughly 200 BCE and 200 CE. Charaka classified it among the Balya (strength-supporting) and Rasayana (rejuvenating) herbs.
c. 600 – 1700 CE
Medieval and Mughal era
Ashwagandha was absorbed into the Unani-Tibb tradition under Mughal patronage. The 16th-century Bhavaprakasha described the herb’s rasa, virya, and vipaka in granular detail.
1700s – 1947
Colonial era
British colonial physicians and botanists encountered ashwagandha through Ayurvedic and Unani practitioners. It was catalogued in Sir George Watt’s Dictionary of the Economic Products of India (1889–1893).
1950s – 1980s
Chemistry and early research
1965 was the inflection point: Israeli chemist David Lavie and colleagues isolated and characterised withaferin A, the first identified withanolide.
1990s – present
Modern revival
The standardised extract KSM-66 was developed by Ixoreal Biomed in 2009 after fourteen years of research, providing a reproducible full-spectrum root extract suitable for reliable clinical testing.
Traditional Ayurvedic context
In classical Ayurveda, ashwagandha was associated with what practitioners describe as vata imbalances and was classified as a Rasayana, a category of herbs intended to support longevity and resilience. It is described as tridoshic (suitable for all three doshas) but particularly grounding for vata and kapha types in classical theory.
A drug, by which the emaciated person becomes corpulent, the weak person strong… is rightly called Rasayana.
— Charaka Samhita, Chikitsa Sthana, Chapter 1
Traditional Ayurvedic descriptions of ashwagandha’s role include use as abalya(strength-supporting) herb in classical formulations, inclusion inmedhya(intellect-related) preparations, use invajikarana(reproductive vitality) formulations, use as a daily rasayana tonic in traditional household practice, and topical preparations described in classical texts for skin and joint contexts. These descriptions reflect classical Ayurvedic categorisation and historical use; they do not constitute claims about the effects of any modern food supplement.
Modern research
Ashwagandha has been studied in several dozen randomised controlled trials over the past two decades, alongside multiple systematic reviews and meta-analyses. The trials are typically small (50–100 participants), short (8–12 weeks), and predominantly conducted in India. The studies described below are reported here as published research; the descriptions are not statements about the effects of any r‑veda product.
| Topic | Study | Participants | Duration |
|---|---|---|---|
| Stress / cortisol | Chandrasekhar 2012 | 64 | 60 days |
| Stress / cortisol | Salve 2019 | 60 | 8 weeks |
| Stress / cortisol | Auddy 2008 | 98 | 60 days |
| Anxiety | Lopresti 2019 | 60 | 60 days |
| Anxiety (review) | Pratte 2014 | 5 trials pooled | – |
| Stress (meta-analysis) | Akhgarjand 2022 | 12 trials pooled | – |
| Sleep | Langade 2019 | 60 | 10 weeks |
| Sleep (elderly) | Kelgane 2020 | 50 | 12 weeks |
| Sleep (meta-analysis) | Cheah 2020 | ~400 pooled | – |
| Physical performance | Wankhede 2015 | 57 | 8 weeks |
| Performance (meta) | Bonilla 2021 | Multiple trials pooled | – |
| Cognition | Choudhary 2017 | 50 | 8 weeks |
| Thyroid markers | Sharma 2018 | 50 | 8 weeks |
| Male fertility | Ambiye 2013 | 46 | 90 days |
| Women’s sexual function | Dongre 2015 | 50 | 8 weeks |
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See full study details
Stress and cortisol research
Chandrasekhar et al. (2012) studied 64 chronically stressed adults given 300mg KSM-66 twice daily for 60 days, measuring perceived stress scores and serum cortisol. Salve et al. (2019) examined 60 healthy adults given 240mg of standardised extract daily.
Sleep research
Langade et al. (2019) studied 60 adults with insomnia given 300mg twice daily for ten weeks, measuring sleep onset latency, total sleep time, and sleep efficiency.
Physical performance research
Wankhede et al. (2015) studied 57 men on a resistance-training programme. Choudhary et al. (2015) reported VO2 max measurements in 50 athletic adults.
Cognitive research
Pingali et al. (2014, Pharmacognosy Research) studied 20 healthy adults over two weeks. Choudhary et al. (2017, Journal of Dietary Supplements) studied 50 adults with mild cognitive impairment over eight weeks. A 2020 review by Ng et al. (Phytotherapy Research) summarised the cognitive evidence base.
Endocrine research
Sharma et al. (2018, Journal of Alternative and Complementary Medicine) studied 50 participants with subclinical hypothyroidism over 8 weeks, measuring TSH, T3, and T4. Lopresti et al. (2019) studied testosterone and DHEA-S markers in 50 overweight men. Ambiye et al. (2013) ran a 46-person open-label trial measuring sperm parameters and testosterone. Dongre et al. (2015, BioMed Research International) studied 50 women over 8 weeks measuring sexual function indices.
How to read this evidence base
Almost all the trials above are small (under 100 participants), short (under 12 weeks), and conducted in India. Many are funded directly or indirectly by extract manufacturers, a common pattern in supplement research that warrants caution. Most use either KSM-66 or Sensoril extracts standardised to specific withanolide content; results may not generalise to lower-quality extracts or leaf-and-stem material. Larger, longer, independent trials in Western populations remain limited. The picture that emerges is consistent in direction across endpoints but provisional in strength.
Forms and preparations
Ashwagandha has historically been consumed in several forms.
- Churna–finely ground dried root powder, traditionally taken with milk or honey
- Decoction–root simmered in water
- Ghrita–root infused into clarified butter (ghee)
- Tincture–alcoholic extract of root material
- Capsule–standardised root extract; the most common modern form and the most dose-accurate option for daily use
Doses used in clinical research range from 240mg to 600mg of standardised root extract per day, taken once or twice daily with food, typically over study periods of 8 to 12 weeks. These figures describe what has been studied in research – they are not dietary recommendations.
Suitability and cautions
Ashwagandha has a long history of traditional use and a generally favourable safety profile in published research. However, several groups should not take ashwagandha or should consult a healthcare professional before use:
- Pregnant or breastfeeding women should avoid ashwagandha.
- People with autoimmune conditions or thyroid disorders should consult a GP before use.
- People taking sedatives, immunosuppressants, thyroid medication, or anti-anxiety medication should consult a GP before use.
- People with a known sensitivity to nightshade plants (Solanaceae) should exercise caution.
- People with liver conditions or who consume alcohol regularly should consult a GP before use; a small number of case reports have linked very high-dose use to liver enzyme elevations.
As with any food supplement, stop use and consult a healthcare professional if you experience any adverse effects.
