Ashwagandha
In short
Summary of findings for quick reference
Ashwagandha is an Ayurvedic rasayana, a restorative root that the classical Indian texts, the Charaka Samhita and the Sushruta Samhita, place among the herbs for strength and recovery. That tradition is deep but regionally narrow. It is a South Asian story, carried in the Ayurvedic and Unani Pharmacopoeias of India, not a herb of Greco-Roman or central European antiquity. There is no Hildegard, no Commission E and no old European household record for it, which is why this entry sits at established historical significance rather than at the top tier.
The modern clinical picture is small and young. Chandrasekhar and colleagues reported reductions in perceived stress and serum cortisol over sixty days in 2012, Lopresti and colleagues found similar directional signals on stress markers in 2019, and Salve and colleagues reported better sleep onset and sleep quality in adults with insomnia, also in 2019. Bonilla and colleagues reviewed strength and testosterone outcomes in men in 2021 and flagged heterogeneity and small samples. The honest reading is a promising but modest evidence base of short trials, with no permitted EFSA health claim.
Safety comes first with this root. Ashwagandha is contraindicated in pregnancy and the same caution is sensible while breastfeeding. It can interact with sedatives, with thyroid medication, where it has been reported to lower TSH and raise free T4, and with immunosuppressants, so it warrants care in autoimmune conditions. The studied preparation is the root, usually a standardised extract of three hundred to six hundred milligrams a day. Note that the European regulator does not hold an established monograph for the herb. The EMA HMPCEuropean Medicines Agency, Committee on Herbal Medicinal Products (HMPC) stated that an EU monograph for the root cannot be established, so any claim of an EMA authorisation should be disregarded.
Clinical evidence ↔ Historical significanceWe display two separate evidence categories: clinical evidence from modern trials and historical significance from documented healing tradition. Both are valuable, but they answer different questions.Read more
In every encyclopedia entry we evaluate two distinct categories of evidence. Clinical evidence as used in trials meets a narrower but scientifically essential bar. At the same time, the hundreds of thousands of plant species worldwide have only partially been captured and tested in modern studies.
Alongside the trial picture our researchers compile a comprehensive overview of where and since when a plant has been used across different traditions of natural medicine. When a plant has been used as a medicinal plant in many cultures across many generations, that historical significance deserves to be visible too.
Our position: a truly informative overview emerges only when both categories sit side by side. We communicate transparently what counts as what.
Overview
Ashwagandha (Withania somnifera) is a small evergreen shrub of the Solanaceae (nightshade) family, native to India, Nepal, and Sri Lanka. The dried root has been used in Ayurvedic tradition for more than two thousand years and is classified there as a rasayana, a category of restorative herbs. The Sanskrit name translates roughly to the smell of a horse, a reference to the distinctive aroma of the fresh root.
Ashwagandha is sometimes called Indian ginseng, but it is not a ginseng species and is not botanically related to the Asian or American ginsengs. There is no EU herbal monograph for the root. The European Medicines Agency Committee on Herbal Medicinal Products (EMA HMPCEuropean Medicines Agency, Committee on Herbal Medicinal Products (HMPC)) concluded in a 2013 final public statement that one could not be established, so in the EU the herb is sold as a food supplement and its traditional use rests on the Ayurvedic record. Modern research interest has grown around a small body of randomised trials on stress, sleep, and cortisol.
History
Ashwagandha is one of the most prominent herbs of the Ayurvedic materia medica. Classical Ayurvedic texts describe it as a rasayana, a restorative tonic used to support resilience and recovery. The dried root, ground into a fine powder, has been the traditional preparation for centuries and remains the basis of most modern products. The name Ashwagandha translates from Sanskrit as the smell of a horse, a reference to the distinctive aroma of the fresh root rather than any folk attribution of equine strength.
In Europe ashwagandha is a relatively new arrival to the wider herbal market. It is not part of Austrian or central European Hausmittel tradition and has no historical place in the Hildegard or Commission E canon. There is no EU herbal monograph for the root. In a final public statement (EMA/HMPC/681519/2012, 2013) the European Medicines Agency Committee on Herbal Medicinal Products (EMA HMPCEuropean Medicines Agency, Committee on Herbal Medicinal Products (HMPC)) concluded that a monograph for Withania somnifera root could not be established, and an unscheduled review was only noted in the November 2024 HMPC minutes. In the EU the herb is sold as a food supplement, and its traditional standing rests on the Ayurvedic record rather than on any EU authorisation.
Mechanism
The main bioactive group in ashwagandha is a family of steroidal lactones known as withanolides. Named withanolides reported in the root include withanolide A, withaferin A, and the glycosides withanoside IV and withanoside V. Standardisation of branded extracts is typically expressed as a percentage of total withanolides, often in the range of one and a half to five per cent.
Mechanistic accounts in the research literature describe ashwagandha as an adaptogen acting on the hypothalamic-pituitary-adrenal (HPA) axis, with proposed effects on cortisol regulation and on neurotransmitter signalling. These mechanisms are drawn from a mix of in-vitro work, animal studies, and small human trials, and the picture is not settled. The link between specific withanolides and any clinical effect in people is plausible but not firmly established. Ashwagandha is best read as a traditional rasayana with a small but growing modern research base.
Modern clinical research on ashwagandha is small in scale and recent in vintage. Chandrasekhar and colleagues published a 2012 randomised controlled trial in adults with chronic stress, reporting reductions in perceived stress and serum cortisol over sixty days with a standardised root extract. Lopresti and colleagues published a 2019 randomised trial measuring stress markers and self-reported anxiety in healthy adults with elevated stress, with similar directional findings. Salve and colleagues published a 2019 randomised trial in adults with insomnia, reporting improvements in sleep onset latency and sleep quality.
Beyond stress and sleep, Bonilla and colleagues published a 2021 review of ashwagandha in resistance-trained men, summarising a heterogeneous body of trials on testosterone and strength outcomes; the review noted positive directional signals but flagged study heterogeneity and small sample sizes as limits on confidence. Across all of this work the EFSA has not granted a permitted health claim for ashwagandha. The trials are short, the products vary (KSM-66 and Sensoril are the two most commonly studied branded extracts), and ashwagandha is best understood as a traditional rasayana with an emerging modern evidence base, not as a clinical treatment.
Evidence
| Outcome | Class | Grade | Effect | Studies |
|---|---|---|---|---|
| Chronic stress and perceived stressChandrasekhar et al. 2012 reported reductions in perceived stress and serum cortisol over sixty days at three hundred milligrams KSM-66 twice daily. Lopresti et al. 2019 reported similar directional findings on stress markers and self-reported anxiety. Body of work is small in scale and trials are short.Adults with chronic stress or elevated stress levels | EmergingEmerging research. Early small trials suggest an effect but await replication. | CEvidence quality grade C. Mixed or limited evidence. Small trials, signals, or traditional use under an EMA HMPC traditional-use monograph. This is an evidence rating, not a product endorsement. | Modest Improvement | |
| Sleep onset latency and sleep qualitySalve et al. 2019 reported improvements in sleep onset latency and self-reported sleep quality in adults with insomnia at three hundred milligrams of a standardised extract twice daily. Other small trials show directionally similar effects.Adults with insomnia or self-reported poor sleep | EmergingEmerging research. Early small trials suggest an effect but await replication. | CEvidence quality grade C. Mixed or limited evidence. Small trials, signals, or traditional use under an EMA HMPC traditional-use monograph. This is an evidence rating, not a product endorsement. | Modest Improvement | |
| Cortisol levelsLopresti et al. 2019 and Chandrasekhar et al. 2012 both reported reductions in serum cortisol over study periods of sixty to ninety days. Effect sizes are modest and trial durations are short.Adults under chronic or elevated stress | EmergingEmerging research. Early small trials suggest an effect but await replication. | CEvidence quality grade C. Mixed or limited evidence. Small trials, signals, or traditional use under an EMA HMPC traditional-use monograph. This is an evidence rating, not a product endorsement. | Modest Improvement | |
| Testosterone and strength outcomes in menBonilla et al. 2021 reviewed the literature on ashwagandha in resistance-trained men, noting positive directional signals on testosterone and strength outcomes but flagging study heterogeneity, small sample sizes, and product variability as material limits on confidence.Resistance-trained men | EmergingEmerging research. Early small trials suggest an effect but await replication. | DEvidence quality grade D. Preliminary signal. A single small trial, pilot result, or laboratory or animal model. Clinical relevance unclear. This is an evidence rating, not a product endorsement. | Mixed Effect |
Usage
Forms and preparation
Most modern ashwagandha products are standardised root extracts in capsule form, often branded as KSM-66 (full-spectrum root) or Sensoril (root and leaf, higher withanolide concentration). The standardised extract is preferred over plain root powder for research-aligned use because the dose is consistent and the withanolide content is declared. Plain root powder remains the classical Ayurvedic preparation, often taken stirred into warm milk in the evening; it requires a much larger daily dose to match the withanolide load of a standardised extract. Take ashwagandha with food. The herb is sometimes mildly stimulating in the morning for some people and mildly settling in the evening for others; experiment with timing. Tinctures and decoctions exist but are less commonly used in the modern supplement market. Do not switch between branded extracts mid-course without comparing the declared withanolide content; the dose-equivalent of one product is not always the dose-equivalent of another.
Dosage
In the research literature the typical daily dose of a standardised root extract is in the range of three hundred to six hundred milligrams per day, taken once or split between morning and evening. The Chandrasekhar 2012 trial used three hundred milligrams of KSM-66 twice daily; the Salve 2019 sleep trial used three hundred milligrams twice daily; the Lopresti 2019 stress trial used two hundred and forty milligrams of a different standardised extract daily. For plain root powder the traditional Ayurvedic dose is much higher, typically three to six grams per day stirred into warm milk or water. Start low. Begin with the lower end of the range (three hundred milligrams of a standardised extract per day) for two weeks and see how you feel before adjusting. Most trials run for sixty to ninety days, so allow a similar timeframe to assess whether the herb is doing anything for you. There is no established upper safe dose for chronic use, and long-term use beyond a few months has not been studied in any depth.
Safety
Look-alikes
FAQs
What is ashwagandha?
Ashwagandha (Withania somnifera) is an Ayurvedic root in the Solanaceae (nightshade) family, traditionally used as a rasayana, a restorative and regenerative herb. In modern use it is most often taken as a standardised root extract in capsule form. In the EU the herb is sold as a food supplement; there is no EU herbal monograph for it, because the EMA HMPC concluded in 2013 that one could not be established. Its traditional use to support people under mental and physical stress and to support sleep rests on the Ayurvedic record. Despite the nickname Indian ginseng, it is not botanically related to Asian or American ginseng.
Can I take ashwagandha during pregnancy?
No. Both the Ayurvedic tradition and the NIH Office of Dietary Supplements list pregnancy as a contraindication for ashwagandha. Concentrated preparations have been associated with abortifacient activity in the older literature. The picture in breastfeeding is poorly studied, so the same caution applies as a conservative default. If you are planning a pregnancy, pregnant, or breastfeeding, talk to your doctor or midwife before using ashwagandha.
How long does it take for ashwagandha to work?
Most clinical trials on ashwagandha run for sixty to ninety days. Allow a similar timeframe before judging whether the herb is doing anything for you. A perceptible effect after the first few doses is the exception, not the rule. Start with the lower end of the dose range and keep a short journal of sleep and how you feel; after a few weeks you can make an honest assessment of whether it is making a difference.
What is the usual dose?
In the research the usual daily dose of a standardised root extract is between three hundred and six hundred milligrams, taken once or split between morning and evening, ideally with food. The most commonly studied branded extracts are KSM-66 (full-spectrum root) and Sensoril (root and leaf, higher withanolide content). For plain root powder the traditional daily amount is much higher, typically three to six grams stirred into warm milk or water. If you switch between products, compare the declared withanolide content first; the dose-equivalent is not always the same.
Legal notice: The depiction of historical significance and traditional use is context within our encyclopedia and not a health claim for any product, not a treatment promise, and not a substitute for medical advice. What may be stated on product labels, product pages, or in advertising is governed by the applicable legal requirements.