Ashwagandha

Place in Ayurveda

A 2023 narrative review states that the root of Withania somnifera is the part used in medicine and that the name ashwagandha comes from ashwa, meaning horse, and gandha, meaning fragrance, referring to the smell of the fresh root. The review describes traditional use as a substance that strengthens the nervous system and links it to the Ayurvedic category of rasayana, and it says use in traditional Indian medicine dates back nearly 3000 years. That date is the review's own general statement and was not checked against primary texts.

The same review lists traditional uses of the root as an aphrodisiac, narcotic, tonic, diuretic, anthelmintic and stimulant. The US National Center for Complementary and Integrative Health (NCCIH) likewise says the plant has been used as a medicinal plant for thousands of years, especially in Ayurvedic medicine. The Machipedia pages on Ayurveda, Ayurvedic Herbal Medicine and Rasayana Therapy describe the wider system, and neither source reviewed here dates specific classical texts.

Spread and modern supplement use

NCCIH describes ashwagandha as an evergreen shrub from parts of India, Africa and the Middle East, and says that supplements typically use the root, the leaf or an extract of either. The narrative review adds that the plant is cultivated beyond India, including in Mediterranean countries, the Himalayan region, Africa and Australia.

Modern trials often test branded, standardized root extracts. Examples named in trial titles and abstracts include Shoden and Witholytin. These are product names used by the research teams, and results for one named extract should not be assumed to apply to another product, to raw root powder or to traditional preparations. The Machipedia pages on Herbal Medicine and Dietary Supplements cover the broader categories.

Names and the botanical species

Ashwagandha is the Sanskrit-derived name used in Ayurveda for Withania somnifera. NCCIH lists Indian ginseng as another common name, and the 2023 narrative review also uses Indian winter cherry. Systematic reviews generally search under ashwagandha, Withania somnifera or both, so these terms refer to the same plant in the sources reviewed.

Adaptogen and rasayana

Several reviews call ashwagandha an adaptogen or anti-stress agent. A 2021 meta-analysis on physical performance describes it as a potent adaptogen, and a 2024 meta-analysis calls it an adaptogenic herb used for psychosomatic disorders. Adaptogen is a modern label used by researchers and marketers and is not a regulatory or classical Ayurvedic category. Rasayana is the Ayurvedic term the narrative review applies to the plant's traditional role, and the Machipedia page on Rasayana Therapy explains the concept.

Root, leaf and extract

Product labels and trial reports use ashwagandha for raw root powder, root extracts, leaf extracts and mixed root and leaf extracts. NCCIH notes that many studies are small and use different preparations. For that reason, a statement about ashwagandha in one trial applies strictly to the preparation that trial tested.

Forms in which it is used

Sources describe ashwagandha taken by mouth as root powder, root extract or leaf extract, usually as a supplement. NCCIH says it contains withanolides, compounds associated in laboratory work with anti-inflammatory and antioxidant effects. This page gives no doses, product choices or preparation steps, because the sources reviewed describe studied amounts for research purposes only and not individual use.

How trials have used it

Trials cited on this page lasted from about two months to six months. A 60-day randomized trial in stressed adults and a 12-week randomized trial in overweight adults with stress and fatigue each compared a standardized extract with placebo. Duration matters for interpretation, because NCCIH states that long-term safety is not established, and most trials ran for only a few weeks to months.

Traditional and popular uses

The narrative review reports a wide range of claimed or studied uses: neuroprotective, sedative and adaptogenic effects, effects on sleep, anti-inflammatory and anti-diabetic properties, and reproductive outcomes. NCCIH lists stress, insomnia, anxiety, testosterone and sperm quality, asthma, athletic performance, cognitive function, diabetes, menopause and female infertility among the uses it addresses.

Thyroid and other claims

The narrative review includes ashwagandha as a possible treatment for hypothyroidism, citing laboratory and animal work, and an animal study in rats with chemically induced hypothyroidism reported improved thyroid hormone measures. These findings are not human trials, and a case report described later on this page documents thyrotoxicosis in a person who used the extract for hypothyroidism. NCCIH states that evidence is not enough for several other claimed uses and that promotion for COVID-19 lacks high-quality support.

Stress and anxiety

A 2014 systematic review (Pratte and colleagues) screened 62 abstracts and included five human trials. All five reported greater improvement on anxiety or stress scales with ashwagandha than with a comparator, but all had unclear or high risk of bias and heterogeneous designs prevented pooling. A 2022 meta-analysis (Akhgarjand and colleagues) of 12 randomized trials with 1,002 participants reported lower anxiety and stress than placebo, with very high heterogeneity and low certainty of evidence for both outcomes.

A 2024 meta-analysis of nine randomized trials in 558 people reported lower scores on the Perceived Stress Scale, the Hamilton Anxiety Scale and serum cortisol than placebo, and four trials reported mild to moderate adverse events. A 12-week trial of an extract in overweight adults with high stress did not find a stress difference from placebo on its primary measure. NCCIH summarizes the evidence as suggesting some preparations may help stress, with evidence for anxiety unclear.

Sleep

A 2021 systematic review and meta-analysis (Cheah and colleagues) pooled five randomized trials with 400 participants and reported a small but significant effect of ashwagandha extract on overall sleep versus placebo, with larger effects in adults diagnosed with insomnia. The authors reported no serious side effects but noted that safety data are limited. The Machipedia page on Melatonin covers another widely used sleep supplement and should not be read as evidence about ashwagandha.

Testosterone, fertility and muscle strength

A 2026 meta-analysis of 20 randomized trials with 1,249 participants reported higher testosterone and muscle strength with ashwagandha, with strength gains seen in physically active people but not in untrained or special populations. A 2021 Bayesian meta-analysis of 13 trials in healthy people reported better physical performance outcomes than placebo and called for more studies in athletic populations. A 2018 systematic review of male infertility found four clinical trials, only one randomized, and concluded that the data were too limited to give robust evidence.

Individual trials are mixed. A 16-week crossover trial in aging, overweight men reported higher testosterone and DHEA-S than placebo but no significant between-group differences in fatigue or vigor, and a 60-day trial found the testosterone change in males did not differ significantly from placebo. NCCIH states that limited evidence suggests testosterone may rise and sperm quality improve over 2 to 4 months.

Quality of the evidence

Across the reviews, the main limits are small trials, short follow-up, differing extracts and very high heterogeneity. Several trials test branded extracts. Funding sources were not examined for this page, so industry sponsorship of individual trials is not assessed here. No source reviewed documents long-term outcomes beyond several months.

Liver injury

A 2020 case series (Björnsson and colleagues) described five people with liver injury attributed to ashwagandha-containing supplements, three in Iceland and two from the US Drug-Induced Liver Injury Network. All developed jaundice after 2 to 12 weeks, the injury was cholestatic or mixed, none developed liver failure, and liver tests normalized within 1 to 5 months in four patients while one was lost to follow-up. Chemical analysis confirmed ashwagandha in available supplements and found no other toxic compounds, though four people also took other supplements.

NCCIH states that liver injury is rare but that a number of cases have been linked to ashwagandha supplements. A 2025 review of safety as a food additive reports multiple cases of liver damage and recommends stronger label warnings. The NIH LiverTox classification could not be opened for this page and is not reported here.

Thyroid, hormones and interactions

A 2022 case report described a 73-year-old woman with supraventricular tachycardia, symptoms of hyperthyroidism and low TSH after two years of self-treating hypothyroidism with ashwagandha root extract; symptoms and blood tests resolved after she stopped it. A single case cannot show how often this occurs. The 2025 review names people with thyroid disorders as a group at risk, and NCCIH advises against use by people with thyroid or autoimmune disorders and before surgery.

NCCIH lists possible interactions with diabetes and blood pressure medicines, immunosuppressants, sedatives, anticonvulsants and thyroid hormone medicines, and advises people with hormone-sensitive prostate cancer to avoid it because it may raise testosterone. The narrative review describes additive effects with benzodiazepines and barbiturates. A 2026 critical review of adverse effects also reports gastrointestinal effects, immune hypersensitivity and endocrine effects, and calls for better pharmacovigilance.

Pregnancy, quality and who should ask a clinician

NCCIH advises avoiding ashwagandha during pregnancy and breastfeeding. The narrative review states that higher doses of root extract can lead to miscarriage, and the 2025 review lists pregnant women among populations at significant risk. The sources reviewed do not describe traditional abortifacient use in detail, so that claim is not made here.

NCCIH notes that the US FDA does not approve dietary supplements before sale and that manufacturers are responsible for safety and labeling. The sources reviewed contain no verified information on quality testing or adulteration of ashwagandha products or on any national ban, so none is reported. Anyone with liver, thyroid or autoimmune conditions, who is pregnant, or who takes prescription medicines should ask a clinician or pharmacist before using it, and it should not replace necessary care.