Ayurveda Codex › Herbs › Ashwagandha

Last verified: April 2026

Ashwagandha

अश्वगंधा — Ashwa (horse) + Gandha (smell) — smell of horse. Named for the root's smell and for its horse-like strengthening properties.

Ashwagandha is probably the most research-verified Ayurvedic herb and one of the most prescribed. Classical texts put it in the Balya (strength-building) and Rasayana (rejuvenating) categories. Modern pharmacology has documented the mechanism: withanolides suppress the HPA axis (the stress hormone pathway). The two bodies of knowledge are consistent — ancient and modern agree on what this herb does.

What it actually does

Ashwagandha does three things with good evidence: reduces cortisol (stress hormone), improves sleep quality, and in men, improves testosterone levels and semen parameters. Everything else — immune modulation, thyroid support, cognitive improvement — has supporting evidence but is less definitive. Classical texts claim much more; the research has confirmed the core claims.

Classical documentation

Charaka Samhita places Ashwagandha in the Vajikarana (reproductive health) and Rasayana (rejuvenating) chapters. The classical indication: Ashwagandha Balya — it gives the strength of a horse. Specifically documented for emaciation, depletion after illness, and as a general tissue-building Rasayana for conditions of Vata and tissue depletion.

Classical preparation: Ashwagandha root powder with warm milk and honey — the simplest and most consistent preparation in the texts. The fat in milk (and ghee if added) helps absorb the withanolides, which are lipophilic compounds.

Key documented effects with clinical trial evidence:

Chandrasekhar et al. (2012) Indian J Psychological Medicine: 240mg KSM-66 extract twice daily for 60 days reduced cortisol by 27.9% vs placebo. DOI:10.4103/0253-7176.106022

Langade et al. (2019) Cureus: 300mg root extract twice daily improved sleep quality scores significantly. DOI:10.7759/cureus.5797

Ambiye et al. (2013) Evidence-Based CAM: 300mg root extract twice daily for 90 days improved semen parameters in oligospermic men. DOI:10.1155/2013/571420

Pratte et al. (2014) Journal of Alternative Medicine: multiple RCTs consistently document anxiolytic effects comparable to low-dose benzodiazepines without dependency.

Classical texts document Ashwagandha as generally safe in normal doses. Modern safety data: well-tolerated at 300-600mg extract daily in clinical trials up to 60-90 days. API specifies root powder (not leaf extract) as the standard preparation. Leaf extract products exist commercially but are not the classically documented part.

Caution

Contraindicated in pregnancy (uterotonic in high doses). Caution in hyperthyroidism (may increase thyroid hormone). Caution with immunosuppressants. Consult a practitioner if on pharmaceutical medications.

Classical preparations

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Ashwagandha with warm milk
Root powder (3-6g) in warm milk with honey. Classical Kshira Paka (milk-processed) preparation. Most commonly documented preparation in Charaka Samhita for Vata conditions and depletion.
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Ashwagandha Ghrita
Root powder processed in ghee. Classical Rasayana preparation specifically for cognitive conditions, neurological weakness, and post-illness depletion. Ghee increases bioavailability of withanolides.
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Ashwagandhadi Lehyam
Classical electuary (sweet jam-like preparation) with multiple herbs. Convenient commercial form preserving classical formulation logic.
Charaka Samhita, Chikitsasthana 1.3

Ashwagandha balya — Ashwagandha is Balya (strength-building). Among all Rasayana herbs, it is specifically indicated for conditions of depletion, emaciation, and Vata aggravation.

Sources

Charaka Samhita Chikitsasthana 1. API Part I, Vol I, Monograph: Withania somnifera (p.29). WHO Monographs Vol 2 (2002): Radix Withaniae. Chandrasekhar et al. (2012) DOI:10.4103/0253-7176.106022. Ambiye et al. (2013) DOI:10.1155/2013/571420.