Ashwagandha

Metadata

Approved Indications

European Regulatory Bodies

Ashwagandha has not been assessed by any of the three major European phytotherapy regulatory bodies:

• Commission E (Germany): No monograph exists. Ashwagandha was not part of the European herbal tradition evaluated by Commission E.
• ESCOP: No monograph. Not within the scope of European scientific cooperative assessment.
• EMA/HMPC: No assessment report or community herbal monograph. The herb is not listed in the EU herbal substances inventory. In 2022, the EMA initiated a review of ashwagandha-containing products following hepatotoxicity case reports, but no formal monograph has resulted.

This is not a negative assessment — these bodies simply never evaluated it, as it originates from the Ayurvedic (Indian) medical tradition rather than the European phytotherapy tradition.

Ayurvedic Pharmacopoeia of India

• Listed: Yes. Ashwagandha (Asvagandha) is an official drug in the Ayurvedic Pharmacopoeia of India (API), Part I.
• Traditional indications: General debility, emaciation, consumption, impotence, aphrodisiac, nervine tonic (balya, vajikara, rasayana). Classified as a Rasayana (rejuvenative) herb.

Indian Pharmacopoeia

• Listed: Yes. Withania somnifera root is included in the Indian Pharmacopoeia with monograph specifications for identity, purity, and assay.

United States

• Dietary supplement: Widely available as a dietary supplement under DSHEA (Dietary Supplement Health and Education Act, 1994).
• GRAS status: KSM-66 ashwagandha root extract received self-affirmed GRAS status (Generally Recognized as Safe) for use in food and beverages.
• NDI notifications: Multiple New Dietary Ingredient (NDI) notifications have been filed with the FDA for various ashwagandha extract preparations.

Conditions Treated

Primary (Strong Evidence)

• Anxiety and perceived stress — Multiple double-blind RCTs demonstrate significant reductions in Hamilton Anxiety Rating Scale (HAM-A), Perceived Stress Scale (PSS), and serum cortisol compared to placebo. Evidence extends to adults with self-reported chronic stress and to those meeting criteria for generalized anxiety.
• Sleep quality — RCTs using both KSM-66 and root powder demonstrate improved sleep onset latency, sleep quality (Pittsburgh Sleep Quality Index), and non-restorative sleep, particularly in stressed or anxious populations.

Secondary (Moderate Evidence)

• Male fertility and testosterone — RCTs demonstrate increased serum testosterone, improved semen parameters (count, motility, volume), and enhanced reproductive hormone profiles in infertile and healthy men.
• Cognitive function — Trials show improvements in reaction time, attention, and executive function in both healthy adults and those with mild cognitive impairment, though sample sizes remain small.
• Exercise performance and recovery — RCTs show improved cardiorespiratory endurance (VO2 max), muscle strength, muscle recovery, and reduced exercise-induced muscle damage.

Emerging/Preclinical

• Anti-inflammatory effects — Withaferin A potently inhibits NF-kB activation and COX-2 expression in vitro and in animal models; limited human data in inflammatory conditions.
• Thyroid modulation — Small RCTs suggest ashwagandha may increase serum T3 and T4 levels in subclinical hypothyroidism (Sharma et al. 2018), though the mechanism is not well characterized and clinical significance remains uncertain.
• Immunomodulation — Preclinical data suggest enhanced NK cell activity and modulation of Th1/Th2 balance; limited clinical translation.

Mechanism of Action

Primary Mechanisms

1. HPA axis modulation and cortisol reduction: Ashwagandha root extract attenuates the hypothalamic-pituitary-adrenal (HPA) axis stress response, resulting in reduced serum and salivary cortisol. This adaptogenic effect is attributed to withanolide-mediated modulation of cortisol synthesis and DHEA-S balance. Multiple RCTs demonstrate 15-30% reductions in serum cortisol relative to placebo, consistent with downregulation of chronic HPA hyperactivation.

2. GABA-mimetic activity: Withanolides and withanolide glycosides act as GABA-A receptor agonists or positive modulators, enhancing inhibitory GABAergic neurotransmission. This mechanism underlies the anxiolytic and sleep-promoting effects. Withanoside IV and its metabolite sominone have demonstrated direct GABAergic activity in electrophysiological studies.

3. Anti-inflammatory signaling (NF-kB and COX-2 inhibition): Withaferin A is a potent inhibitor of IKK-beta-mediated NF-kB activation. It covalently modifies cysteine residues on IKK-beta, preventing phosphorylation and nuclear translocation of NF-kB. Downstream effects include reduced COX-2, iNOS, and pro-inflammatory cytokine expression (TNF-alpha, IL-1beta, IL-6).

Secondary Mechanisms

4. Serotonergic and cholinergic modulation: Animal studies demonstrate that ashwagandha root extract modulates serotonin (5-HT1A and 5-HT2 receptor) signaling and enhances acetylcholinesterase inhibition (via sitoindosides VII-X), providing a plausible mechanism for anxiolytic and cognitive effects, respectively.

5. Antioxidant and neuroprotective activity: Withanolides enhance endogenous antioxidant enzyme activity (superoxide dismutase, catalase, glutathione peroxidase) and reduce lipid peroxidation. In animal models of neurodegeneration, ashwagandha extract reduces amyloid-beta aggregation and promotes neurite outgrowth via sominone.

6. Hormonal modulation: Ashwagandha influences the hypothalamic-pituitary-gonadal axis, with RCT evidence for increased testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) in men. The mechanism may involve reduced cortisol-mediated suppression of gonadal function (cortisol-testosterone inverse relationship) and direct effects on Leydig cell steroidogenesis.

Key Pharmacological Note

Ashwagandha’s adaptogenic profile is distinct from other adaptogens: whereas Rhodiola rosea primarily modulates catecholamine and monoamine signaling, and Eleutherococcus senticosus acts broadly on nonspecific stress resistance, ashwagandha’s effects are anchored in HPA axis/cortisol modulation and GABAergic activity. This mechanistic profile positions it more specifically for anxiety, stress, and sleep rather than fatigue and physical endurance.

Clinical Evidence Summary

Ashwagandha has a substantially larger clinical evidence base than most non-European adaptogenic herbs, with multiple independent RCTs using standardized extracts.

Anxiety and Stress RCTs

Sleep RCTs

Testosterone and Male Fertility RCTs

Exercise Performance RCTs

Systematic Reviews and Meta-Analyses

Evidence Limitations

• Many RCTs are industry-funded (by KSM-66 or Sensoril manufacturers), introducing potential bias.
• Sample sizes, while adequate for pilot-level evidence, are generally modest (n=40-98).
• Heterogeneity across trials in extract type, dose, standardization, and outcome measures limits meta-analytic precision.
• Most studies are conducted in Indian populations; cross-cultural generalizability has been less established, though Lopresti et al. (2019a) was conducted in Australia.
• Long-term efficacy and safety data beyond 12 weeks remain sparse.

Safety Profile

General Assessment

Ashwagandha root extract is generally well-tolerated in clinical trials at doses up to 600 mg/day for up to 12 weeks. The herb has a long history of traditional use in Ayurvedic medicine (>3000 years). However, post-marketing surveillance has identified rare but serious hepatotoxicity signals that warrant clinical attention.

Contraindications

• Pregnancy: Contraindicated. Ashwagandha has demonstrated abortifacient activity in animal studies (increased uterine contractions and embryotoxicity at high doses). No human safety data in pregnancy. Traditional Ayurvedic texts also advise avoidance during pregnancy.
• Lactation: Insufficient data. Avoid until safety is established.
• Hyperthyroidism or Graves’ disease: Contraindicated. Ashwagandha may stimulate thyroid hormone production (increase T3 and T4), potentially exacerbating hyperthyroid states.
• Solanaceae allergy: Ashwagandha belongs to the nightshade family (Solanaceae). Individuals with known allergy to tomatoes, peppers, or other Solanaceae should exercise caution.
• Pre-surgical: Discontinue at least 2 weeks before surgery due to potential additive sedation with anesthetic agents and possible effects on thyroid function.

Drug Interactions

• Thyroid hormones (levothyroxine, liothyronine): Ashwagandha may increase endogenous thyroid hormone production, potentially necessitating dose adjustment of exogenous thyroid medication. Sharma et al. (2018) documented significant increases in serum T4 in patients with subclinical hypothyroidism taking 600 mg root extract daily. Monitoring of thyroid function is advised.
• Immunosuppressants (cyclosporine, tacrolimus, azathioprine): Ashwagandha has demonstrated immunostimulatory activity (enhanced NK cell activity, modulation of cytokine profiles) in preclinical and small clinical studies. Concurrent use may theoretically counteract immunosuppressive therapy. Avoid in transplant recipients and autoimmune patients on immunosuppressants.
• Sedatives and CNS depressants (benzodiazepines, barbiturates, alcohol, zolpidem): GABA-mimetic activity creates a mechanistic basis for additive sedation. Clinical case reports are lacking, but the pharmacological rationale is clear. Advise caution and monitor for excessive sedation.
• Diabetes medications (insulin, sulfonylureas, metformin): Some trials report modest reductions in fasting blood glucose. Potential for additive hypoglycemia when combined with glucose-lowering agents; monitor blood glucose.
• Antihypertensives: Ashwagandha may modestly lower blood pressure; additive hypotensive effect is theoretically possible.

Side Effects (at recommended doses)

• Common: Gastrointestinal discomfort (nausea, diarrhea, abdominal pain) — reported in approximately 5-10% of trial participants, generally mild and transient.
• Uncommon: Drowsiness, sedation (consistent with GABA-mimetic activity), headache, upper respiratory symptoms.
• Rare but serious: Hepatotoxicity. A series of case reports emerged in the early 2020s (Iceland: Bjornsson et al. 2020; several cases reported to the European DGAV pharmacovigilance network) documenting liver injury associated with ashwagandha supplementation. The EMA and several Nordic regulatory agencies issued safety signals. The mechanism is unclear (possible idiosyncratic hepatotoxicity or contamination-related). The absolute risk appears very low relative to widespread use, but liver function monitoring is advisable in long-term users.
• Thyroid effects: Subclinical increases in T3 and T4 have been documented even in euthyroid individuals; generally clinically insignificant but relevant in patients with thyroid disorders.

Toxicology

• Acute oral LD50 in mice: >2000 mg/kg (KSM-66 extract), indicating very low acute toxicity.
• No evidence of genotoxicity or mutagenicity in standard Ames test and chromosomal aberration assays (KSM-66 toxicology dossier).
• A 90-day subchronic toxicity study in rats (KSM-66, 2000 mg/kg/day) showed no significant adverse effects on organ histopathology, hematology, or clinical chemistry.

Clinical Dosage

KSM-66 (Full-Spectrum Root Extract)

• Standard dose: 300 mg twice daily (600 mg/day total)
• Standardization: >=5% withanolides by HPLC
• This is the most extensively studied extract form in clinical trials
• Lower dose range: 240-300 mg/day has shown efficacy for anxiety in some trials (Lopresti et al. 2019a)

Sensoril (Root and Leaf Extract)

• Standard dose: 125-250 mg once daily
• Standardization: >=10% withanolide glycosides, >=32% oligosaccharides
• Auddy et al. (2008) found 250 mg/day to be the optimal dose for stress reduction

Unstandardized Root Powder

• Traditional Ayurvedic dose: 3-6 g/day of dried root powder, typically taken with warm milk (ksheerapaka) or ghee
• Note: Bioactive compound concentration varies significantly with unstandardized preparations; clinical predictability is lower

Withanolide Glycoside-Rich Extract (for sleep)

• Dose: 120 mg/day standardized to withanolide glycosides (Deshpande et al. 2020)
• Specifically studied for sleep outcomes

General Dosing Notes

• Ashwagandha is typically taken with food to reduce gastrointestinal side effects.
• Onset of clinical effects generally requires 4-8 weeks of consistent use.
• Morning dosing is preferred for stress/anxiety indications; evening dosing for sleep indications.
• KSM-66 and Sensoril are not interchangeable on a milligram basis due to different extraction methods and withanolide compositions.

Sources

• Chandrasekhar K, Kapoor J, Anishetty S. A prospective, randomized double-blind, placebo-controlled study of safety and efficacy of a high-concentration full-spectrum extract of ashwagandha root in reducing stress and anxiety in adults. Indian J Psychol Med. 2012;34(3):255-262
• Salve J, Pate S, Debnath K, Langade D. Adaptogenic and anxiolytic effects of ashwagandha root extract in healthy adults: a double-blind, randomized, placebo-controlled clinical study. Cureus. 2019;11(12):e6466
• Langade D, Kanchi S, Salve J, Debnath K, Ambegaokar D. Efficacy and safety of ashwagandha (Withania somnifera) root extract in insomnia and anxiety: a double-blind, randomized, placebo-controlled study. Cureus. 2019;11(9):e5797
• Lopresti AL, Smith SJ, Malvi H, Kodgule R. An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: a randomized, double-blind, placebo-controlled study. Medicine (Baltimore). 2019;98(37):e17186
• Lopresti AL, Drummond PD, Smith SJ. A randomized, double-blind, placebo-controlled, crossover study examining the hormonal and vitality effects of ashwagandha (Withania somnifera) in aging, overweight males. Am J Mens Health. 2019;13(2):1557988319835985
• Auddy B, Hazra J, Mitra A, Abedon B, Ghosal S. A standardized Withania somnifera extract significantly reduces stress-related parameters in chronically stressed humans: a double-blind, randomized, placebo-controlled study. JANA. 2008;11(1):50-56
• Cooley K, Szczurko O, Perri D, et al. Naturopathic care for anxiety: a randomized controlled trial ISRCTN78958974. PLoS One. 2009;4(8):e6628
• Choudhary D, Bhatt S, Joshi S. Body weight management in adults under chronic stress through treatment with ashwagandha root extract: a double-blind, randomized, placebo-controlled trial. J Evid Based Complementary Altern Med. 2017;22(1):96-106
• Wankhede S, Langade D, Joshi K, Sinha SR, Bhattacharyya S. Examining the effect of Withania somnifera supplementation on muscle strength and recovery: a randomized controlled trial. J Int Soc Sports Nutr. 2015;12:43
• Choudhary B, Shetty A, Langade DG. Efficacy of Ashwagandha (Withania somnifera [L.] Dunal) in improving cardiorespiratory endurance in healthy athletic adults. Ayu. 2015;36(1):63-68
• Ahmad MK, Mahdi AA, Shukla KK, et al. Withania somnifera improves semen quality by regulating reproductive hormone levels and oxidative stress in seminal plasma of infertile males. Fertil Steril. 2010;94(3):989-996
• Deshpande A, Irani N, Balkrishnan R, Benny IR. A randomized, double blind, placebo controlled study to evaluate the effects of ashwagandha (Withania somnifera) extract on sleep quality in healthy adults. Sleep Med. 2020;72:28-36
• Sharma AK, Basu I, Singh S. Efficacy and safety of ashwagandha root extract in subclinical hypothyroid patients: a double-blind, randomized placebo-controlled trial. J Altern Complement Med. 2018;24(3):243-248
• Pratte MA, Nanavati KB, Young V, Morley CP. An alternative treatment for anxiety: a systematic review of human trial results reported for the Ayurvedic herb ashwagandha (Withania somnifera). J Altern Complement Med. 2014;20(12):901-908
• Bonilla DA, Moreno-Franco YA, Rawson ES, et al. An umbrella/systematic review and meta-analysis of the effects of Withania somnifera supplementation on testosterone and cortisol levels. Phytother Res. 2021 (Corrected: Bonilla DA, et al. Effects of ashwagandha on measures of stress, anxiety, and well-being: a systematic review and meta-analysis. J Herb Med. 2021)
• Perez-Gomez J, Villafaina S, Adsuar JC, et al. Effects of ashwagandha (Withania somnifera) on VO2max: a systematic review and meta-analysis. Nutrients. 2020;12(4):1119
• Bjornsson HK, Bjornsson ES, Avula B, et al. Ashwagandha-induced liver injury: a case series from Iceland and the US Drug-Induced Liver Injury Network. Liver Int. 2020;40(4):825-829
• Mirjalili MH, Moyano E, Bonfill M, Cusido RM, Palazon J. Steroidal lactones from Withania somnifera, an ancient plant for novel medicine. Molecules. 2009;14(7):2373-2393
• Singh N, Bhalla M, de Jager P, Gilca M. An overview on ashwagandha: a Rasayana (rejuvenator) of Ayurveda. Afr J Tradit Complement Altern Med. 2011;8(5 Suppl):208-213
• Ayurvedic Pharmacopoeia of India. Part I, Vol. I. Government of India, Ministry of Health and Family Welfare

Connections

• Compare with other adaptogens: rhodiola (catecholamine/monoamine modulation — more stimulating, suited for fatigue), eleuthero (broad nonspecific stress resistance)
• Compare with other GABA-modulating anxiolytics: magnolia-bark (honokiol — GABA-A positive allosteric modulation), valerian (valerenic acid — GABA-A and GABA reuptake), kava (kavalactones — lipid membrane GABA-A modulation)
• The HPA axis/cortisol-lowering mechanism overlaps with that of magnolia bark (Relora) and phosphatidylserine
• Ashwagandha’s testosterone-modulating effects position it at the intersection of nervous-system-mood and men’s health categories
• Ashwagandha represents the growing integration of Ayurvedic-origin herbs into Western evidence-based phytotherapy, paralleling the trajectory of turmeric/curcumin