Quick summary

Ashwagandha (Withania somnifera) is an adaptogenic herb traditionally used in Ayurvedic medicine. It has been investigated in numerous clinical studies for its potential effects on stress, anxiety, depression, cognitive function, sleep quality, hormonal modulation, physical performance, and quality of life in various populations. While several randomized controlled trials (RCTs) and meta-analyses suggest possible benefits, the evidence is sometimes limited by heterogeneity, small sample sizes, and methodological variability. Safety data from clinical trials indicate that ashwagandha is generally well tolerated with few reported adverse effects, although rare neurological events have been documented. Further high-quality, large-scale, and standardized clinical trials are needed to clarify clinical utility, safety, dosing, and contraindications.

What is it?

Ashwagandha, scientifically known as Withania somnifera, is a medicinal herb commonly used in traditional Ayurvedic medicine. It is considered an adaptogen, meaning it may help the body adapt to stress. The root is the primary part used for supplements and traditional remedies.

Traditional uses

Ashwagandha has traditionally been employed to promote vitality, reduce fatigue, support mental health, enhance cognitive function, and improve overall well-being. It is also used in Ayurveda for conditions related to stress, low energy, hormonal imbalances, and inflammation.

Active compounds

Key constituents of ashwagandha include withanolides (steroidal lactones), alkaloids, sitoindosides, and other flavonoids. These compounds are thought to contribute to its proposed adaptogenic, anti-inflammatory, antioxidant, and neuroprotective effects.

Potential benefits with evidence levels

  • Anxiety reduction (Human clinical evidence): Multiple RCTs and meta-analyses suggest ashwagandha supplementation may significantly reduce anxiety symptoms compared to placebo, showing moderate to large effect sizes.
  • Stress reduction and cortisol lowering (Human clinical evidence): RCTs demonstrate reductions in biological stress markers such as cortisol; some meta-analyses confirm significant decreases. Patient-reported stress outcomes are mixed.
  • Depression symptom improvement (Limited human clinical evidence): Some studies indicate potential improvement in depressive symptoms, though data are limited and heterogeneous compared to anxiety evidence.
  • Sleep quality enhancement (Human clinical evidence): Systematic reviews and RCTs show improvements in sleep quality and reductions in sleep disturbances.
  • Cognitive performance improvement (Preliminary human clinical evidence): Early studies in adults and children suggest benefits on memory, processing speed, and executive function, but more research is needed.
  • Hormonal modulation (Human clinical evidence): Meta-analyses report decreases in cortisol and increases in testosterone in men; effects on thyroid hormones and serotonin are possible but less conclusive.
  • Quality of life and physical function in cancer patients (Human clinical evidence with limitations): Network meta-analyses indicate potential improvements in quality of life, fatigue, pain, nausea, and functioning in breast cancer patients.
  • Supportive treatment for hormonal disorders in women (PCOS and PMS) (Predominantly preclinical and extrapolated human evidence): Limited evidence suggests possible hormonal and neuropsychiatric symptom modulation; robust clinical trials are lacking.
  • Improvement of muscle strength and exercise performance (Human clinical evidence): Systematic reviews suggest potential benefits for muscle strength, endurance, and recovery in athletes and healthy individuals.
  • Neuroprotective and adaptogenic effects (Preclinical and limited human clinical evidence): Exhibits antioxidant, anti-inflammatory, and immunomodulatory properties that may support neuroprotection, though clinical evidence is limited.

Side effects

Clinical trials report ashwagandha is generally well tolerated at typical doses of 200–1000 mg daily for up to six months. Common mild adverse events include gastrointestinal symptoms and mild to moderate transient effects. Rarely, acute-onset dystonia (a neurological movement disorder) has been reported in isolated case reports. No consistent patterns of serious adverse effects have been observed, and side effects are generally comparable to placebo.

Drug interactions

Ashwagandha may potentially interact with medications metabolized by cytochrome P450 enzymes due to its effects on metabolic pathways. Caution is also advised when combining ashwagandha with central nervous system depressants because of possible additive sedation. However, there is insufficient direct clinical evidence detailing specific drug interactions, and further investigation is warranted.

Who should avoid it

Pregnant and breastfeeding women are generally advised to avoid ashwagandha unless under medical supervision because of limited safety data and traditional concerns regarding abortifacient effects. Individuals with autoimmune diseases or those on immunosuppressive therapy should exercise caution due to ashwagandha’s immunomodulatory properties. There are no formally established contraindications based on robust clinical evidence.

Evidence limitations

  • Many studies have small sample sizes and short follow-up durations.
  • Clinical heterogeneity exists in extract preparations, dosages, and outcome measures.
  • Predominance of moderate risk of bias and methodological variability among trials.
  • Limited availability of large-scale, long-term, randomized, placebo-controlled trials.
  • Scarcity of standardized extract usage and dosing protocols.
  • Potential funding-related biases in some clinical studies.
  • Lack of comprehensive safety and pharmacokinetic interaction data.
  • Sparse data in pregnant and breastfeeding populations.
  • Heavy reliance on preclinical data for many proposed mechanisms and indications.

References

Last reviewed

June 2026

Informational disclaimer: This page is for informational purposes only and does not constitute medical advice. Ashwagandha supplements should not replace professional medical treatment. Consult a healthcare provider before starting any new supplement, especially if you have underlying health conditions, are pregnant, breastfeeding, or are taking other medications.