Herbal Monograph
Ashwagandha
Withania somnifera (L.) Dunal
Solanaceae (Nightshade family)
Premier Ayurvedic adaptogen for resilient stress response, calm vitality, and deep restorative strength
Overview
Plant Description
Erect, evergreen or deciduous shrubby perennial, 30-150 cm tall (typically 60-100 cm in cultivation). Stems branching, covered with dense, stellate (star-shaped) trichomes giving a grey-green, tomentose appearance. Leaves simple, alternate, ovate to elliptic, 5-12 cm long, entire margins, dull green above, pubescent below with stellate hairs. Flowers small, 4-6 mm, greenish-yellow to pale yellow, bell-shaped, borne in axillary clusters of 4-6; calyx 5-lobed, enlarging in fruit to form a papery, lantern-like enclosure (characteristic of Solanaceae). Fruit a small, round berry, 5-8 mm diameter, orange-red when ripe, enclosed within the persistent, inflated calyx. Seeds numerous, small, flat, yellow, kidney-shaped. Root system consists of a stout, fleshy taproot, whitish-brown externally, white internally, with a characteristic horse-like odor when fresh (the Sanskrit name 'ashwagandha' translates to 'smell of the horse,' referring both to the root's odor and the traditional belief that it imparts the vitality and strength of a horse).
Habitat
Dry and subtropical regions. Grows in dry, stony soils, waste places, and open ground. Tolerates poor, alkaline soils and semi-arid conditions. Prefers full sun and well-drained soil. Altitude range: sea level to approximately 1,500 m. Does not tolerate waterlogged conditions or heavy frost.
Distribution
Native to the Indian subcontinent (India, Pakistan, Sri Lanka), extending through the Middle East (Yemen, Oman, Jordan) and into parts of North and East Africa (Egypt, Ethiopia, Somalia, South Africa). Naturalized in parts of the Mediterranean basin and the Canary Islands. Commercially cultivated in India (primarily Madhya Pradesh, Rajasthan, Maharashtra, Gujarat, and Andhra Pradesh), also grown in Israel, parts of Africa, and increasingly in the United States and Europe for the growing supplement market.
Parts Used
Root (Ashwagandhae radix)
Preferred: Dried root powder (churna) for traditional preparations; standardized root extract (typically 2.5-5% withanolides) for modern clinical applications; root powder in warm milk (traditional Ayurvedic Rasayana preparation)
The root is the primary medicinal part recognized in Ayurvedic pharmacopeia, WHO monographs, and most clinical research. The dried root contains the highest concentrations of withanolides (particularly withaferin A and withanolide D) and sitoindosides. Root quality is assessed by withanolide content, which varies by chemotype, geographic origin, and cultivation conditions. Both whole root powder and standardized extracts are used commercially.
Leaf
Preferred: Dried leaf for research extracts; not commonly used in traditional preparations as a standalone
Leaves are a secondary medicinal part with emerging research interest. Historically used less frequently than root in Ayurvedic medicine but gaining attention for potentially higher withaferin A content. Leaf extracts have been studied for anti-inflammatory, anticancer, and antimicrobial properties in preclinical models. Some commercial extracts use a combination of root and leaf. The distinction between root-only and root-plus-leaf products is important for clinical applicability, as constituent profiles differ significantly.
Key Constituents
Withanolides (steroidal lactones)
Withanolides are the primary bioactive constituents of ashwagandha and the principal basis for pharmacological standardization. Over 40 withanolides have been identified in W. somnifera. They are C28 steroidal lactones built on an ergostane skeleton. Key mechanisms include: inhibition of NF-kB pathway (anti-inflammatory), modulation of HPA axis (adaptogenic/cortisol-reducing), enhancement of GABA-mimetic activity (anxiolytic), immunomodulation through Th1/Th2 balancing, and neuroprotection through reduction of beta-amyloid-induced toxicity and promotion of neurite outgrowth. Most standardized commercial extracts are standardized to total withanolide content (typically 2.5-5% by gravimetry or 1-10% by HPLC, depending on methodology). It is important to note that different analytical methods yield different withanolide percentages, which complicates product comparison.
Alkaloids
The alkaloid fraction of ashwagandha includes approximately 12 identified alkaloids, predominantly piperidine and tropane types. Total alkaloid content in the root is relatively low (0.13-0.31%). While early research attributed the sedative and adaptogenic properties of ashwagandha partly to its alkaloids (particularly withanine and somniferine), current understanding emphasizes the withanolides as the primary bioactive constituents. The alkaloids may contribute to the overall pharmacological profile through additive or synergistic effects but are not the basis for modern standardization.
Saponins (Sitoindosides and withanosides)
The sitoindosides (glycowithanolides) are considered important contributors to ashwagandha's adaptogenic and nootropic activity. Bhattacharya and colleagues demonstrated that sitoindosides VII-X and withaferin A exhibit antioxidant activity in rat brain frontal cortex and striatum, enhancing superoxide dismutase, catalase, and glutathione peroxidase activity. This antioxidant mechanism in neural tissue provides a pharmacological rationale for the traditional use of ashwagandha as a medhya rasayana (cognitive tonic). The glycoside forms may have improved bioavailability compared to free withanolides.
Other constituents
The non-withanolide constituents contribute to the overall nutritive and tonic properties of ashwagandha root. The iron content is clinically relevant in populations with iron-deficiency anemia. Free amino acids including GABA and tryptophan may complement the withanolide-mediated anxiolytic and sleep effects. The starchy, nutritive nature of the root aligns with its traditional classification as a Brimhana (nourishing/building) and Rasayana (rejuvenative) herb in Ayurveda, where it is given with warm milk and ghee to debilitated or convalescing patients.
Herbal Actions
Helps the body adapt to stress and restore homeostasis
The defining pharmacological action of ashwagandha. Adaptogens increase the body's nonspecific resistance to physical, chemical, and biological stressors while normalizing physiological function. Ashwagandha modulates the hypothalamic-pituitary-adrenal (HPA) axis, reducing elevated cortisol levels during chronic stress. Chandrasekhar et al. (2012) demonstrated significant reduction in serum cortisol levels (−27.9% vs. placebo) in chronically stressed adults. The adaptogenic mechanism involves regulation of key stress mediators including cortisol, heat shock proteins (Hsp70), and the JNK-1 signaling pathway. Unlike stimulant adaptogens (e.g., Panax ginseng), ashwagandha is classified as a calming adaptogen, supporting energy and resilience while simultaneously reducing anxiety.
[1, 5, 15, 19]Reduces anxiety
Well-supported anxiolytic activity demonstrated in multiple RCTs. Lopresti et al. (2019) found significant reductions in Hamilton Anxiety Rating Scale (HAM-A) scores with ashwagandha extract (240 mg/day) compared to placebo. The anxiolytic mechanism involves GABAergic modulation — withanolides and their metabolites act as GABA-mimetic agents at GABA-A receptors, and ashwagandha extracts enhance GABA signaling. Additional mechanisms include HPA axis regulation (cortisol reduction), serotonergic modulation, and reduction of stress-induced neuroinflammation. The calming, anxiolytic quality distinguishes ashwagandha from stimulant adaptogens and aligns with the species name 'somnifera' (sleep-inducing).
[5, 6, 10]Modulates and balances immune function
Ashwagandha modulates immune function bidirectionally depending on context. In immunosuppressed states, it enhances innate and adaptive immune responses: increases natural killer cell activity, macrophage phagocytosis, and Th1 cytokine production (IL-2, IFN-gamma). In overactive immune states and chronic stress-induced immune dysregulation, it reduces excessive inflammatory cytokines (IL-6, TNF-alpha, CRP). Withanolide D and withaferin A are the primary immunoactive constituents. This bidirectional activity is consistent with the adaptogenic classification — normalizing immune function rather than simply stimulating or suppressing it.
[1, 13, 15]Reduces inflammation
Demonstrated anti-inflammatory activity through multiple mechanisms. Withaferin A inhibits NF-kB activation, a master regulator of inflammatory gene expression. Withanolides also suppress COX-2, iNOS, and pro-inflammatory cytokines (TNF-alpha, IL-1beta, IL-6) in preclinical models. Clinical trials have shown reductions in C-reactive protein (CRP) and other inflammatory markers. The anti-inflammatory action contributes to therapeutic effects across multiple body systems including musculoskeletal (joint pain), nervous (neuroinflammation), and immune (chronic inflammation).
[1, 15]Supports and calms the nervous system
Acts as a nervine tonic (trophorestorative) to the nervous system. Supports and nourishes nervous system function during periods of stress, depletion, and nervous exhaustion. The nervine action encompasses the anxiolytic, sleep-promoting, and neuroprotective effects. Traditional Ayurvedic classification as a medhya rasayana (intellect-promoting rejuvenative) reflects this nervine trophorestorative quality. Distinguished from stimulant nervines by its calming, restorative action.
[1, 15]Promotes sleep and deep relaxation
Mild sedative and sleep-promoting activity, consistent with the species name 'somnifera' (sleep-inducing). Langade et al. (2019) demonstrated significant improvement in sleep quality (Pittsburgh Sleep Quality Index) and sleep onset latency with ashwagandha root extract (600 mg/day) over 10 weeks. The sedative effect is gentle and non-narcotic, more accurately described as sleep-promoting rather than strongly sedating. GABAergic activity of withanolides (GABA-mimetic effects) and the calming adaptogenic action on the HPA axis both contribute. Triethylene glycol identified in leaves as a potential sleep-inducing component in animal studies.
[6, 8]Prevents or slows oxidative damage to cells
Demonstrates significant antioxidant activity through direct free radical scavenging and through upregulation of endogenous antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase) in neural and hepatic tissue. Sitoindosides VII-X and withaferin A enhance antioxidant enzyme activity in the brain. The antioxidant action is particularly relevant to neuroprotective and hepatoprotective effects and contributes to the overall anti-aging/rejuvenative (Rasayana) properties in Ayurvedic classification.
[1, 15]Relieves pain
Mild analgesic effects demonstrated in animal models. The analgesic activity is secondary to the anti-inflammatory action (via NF-kB and COX-2 inhibition) rather than a direct central analgesic mechanism. Clinically relevant for musculoskeletal pain, joint stiffness, and inflammatory pain conditions. Ramakanth et al. (2016) found improvements in pain scores in patients with knee joint pain.
[1]Stimulates and enhances immune response
In addition to its broader immunomodulating activity, ashwagandha demonstrates a mild immunostimulant effect that is most apparent in immunosuppressed or depleted states. Enhances white blood cell counts, natural killer cell activity, and macrophage function. Mikolai et al. (2009) pilot study showed increases in CD4+ and CD56+ immune cell activation. This action is context-dependent and secondary to the broader immunomodulating action.
[13]Therapeutic Indications
Nervous System
Stress and anxiety disorders
The most extensively studied indication. Multiple RCTs demonstrate significant reduction in stress and anxiety. Chandrasekhar et al. (2012): 64 subjects with chronic stress, 300 mg standardized root extract twice daily for 60 days; significant reductions in all stress-assessment scales (PSS, GHQ-28, DASS) and 27.9% reduction in serum cortisol vs. placebo (P < 0.0006). Lopresti et al. (2019): 60 adults with self-reported anxiety, 240 mg standardized extract daily for 60 days; significant reduction in HAM-A scores vs. placebo (P < 0.05), significant reduction in morning cortisol (P = 0.031). Pratte et al. (2014) systematic review of 5 RCTs concluded ashwagandha intervention resulted in greater score improvements on anxiety and stress scales than placebo in all studies reviewed.
[5, 6, 10]Insomnia and sleep disturbance
Langade et al. (2019): double-blind RCT of 150 healthy subjects with sleep complaints, 120 mg standardized extract or 300 mg full-spectrum root extract twice daily for 10 weeks. Significant improvement in sleep quality (PSQI), sleep onset latency, and sleep efficiency vs. placebo. The sleep-promoting effect appears mediated by both GABAergic activity and cortisol reduction. Traditionally the root powder taken with warm milk at bedtime is the classical Ayurvedic approach for insomnia.
[6, 8]Cognitive function and memory
Classified as a medhya rasayana (intellect-promoting rejuvenative) in Ayurveda. Choudhary et al. (2017) RCT showed significant improvement in immediate and general memory, attention, and information processing speed with 300 mg root extract twice daily for 8 weeks. Neuroprotective mechanisms include reduction of oxidative stress in brain tissue (via enhanced SOD and catalase), reduction of beta-amyloid toxicity, and promotion of neurite outgrowth (via withanoside IV metabolite sominone). Preclinical evidence is extensive; clinical evidence is emerging but limited.
[12, 15]Endocrine System
HPA axis dysregulation and chronic stress-related cortisol elevation
Ashwagandha's action on the HPA axis is central to its adaptogenic mechanism. Multiple clinical trials demonstrate significant reduction in elevated cortisol levels. Chandrasekhar et al. (2012) showed 27.9% cortisol reduction. The modulation appears to be normalizing rather than simply suppressive — cortisol is reduced when elevated but there is no evidence of pathological suppression of normal cortisol function.
[5, 6]Subclinical hypothyroidism
Sharma et al. (2018) RCT of 50 subjects with subclinical hypothyroidism showed ashwagandha root extract (600 mg/day for 8 weeks) significantly improved serum TSH, T3, and T4 levels compared to placebo. This thyroid-stimulating effect is clinically important: while potentially beneficial in hypothyroidism, it is a contraindication in hyperthyroidism and requires monitoring in patients on thyroid hormone replacement. The mechanism may involve direct stimulation of thyroid hormone synthesis or modulation of the HPT axis.
[11]Male reproductive and sexual health
Traditionally used as Vajikara (aphrodisiac) in Ayurveda. Ahmad et al. (2010) demonstrated improvement in semen quality parameters (concentration, motility, volume) in infertile men after 3 months of root powder treatment. Wankhede et al. (2015) study on muscle strength also noted increased testosterone levels in the ashwagandha group. Mechanism likely involves both HPA axis normalization (reducing stress-induced reproductive suppression) and direct effects on gonadal function.
[7, 14]Immune System
Immune deficiency and stress-related immunosuppression
Ashwagandha enhances immune cell activity when suppressed by stress or illness. Mikolai et al. (2009) pilot study demonstrated significant increases in CD4+ T-cell and CD56+ natural killer cell activation markers with ashwagandha root extract. The dual immunomodulating action (enhancing when suppressed, dampening when overactive) makes it appropriate for chronic stress-related immune compromise without risk of immune overstimulation.
[1, 13]Chronic inflammation
The anti-inflammatory mechanism through NF-kB inhibition and cytokine modulation is well-documented in preclinical studies. Clinical evidence shows reduction in inflammatory markers including CRP. Particularly relevant for chronic low-grade inflammation associated with stress, metabolic syndrome, and aging.
[1, 15]Musculoskeletal System
Muscle strength, recovery, and exercise performance
Wankhede et al. (2015): double-blind RCT of 57 young males undergoing resistance training, 300 mg root extract twice daily for 8 weeks. Ashwagandha group showed significantly greater increases in muscle strength (bench press 1RM and leg extension), muscle size (arm and chest measurements), reduction in exercise-induced muscle damage (serum creatine kinase), and increase in testosterone levels, with greater body fat percentage reduction vs. placebo. The anabolic and recovery-enhancing effects are consistent with the traditional Ayurvedic classification as Balya (strength-promoting).
[7]Joint pain and osteoarthritis
Anti-inflammatory and analgesic properties suggest benefit in inflammatory joint conditions. Ramakanth et al. (2016) study showed improvement in pain and physical function in knee joint pain. The anti-inflammatory mechanism (NF-kB, COX-2 inhibition) provides a pharmacological rationale. Further clinical trials are needed to establish efficacy for osteoarthritis.
[1]Reproductive System
Male infertility and oligospermia
Ahmad et al. (2010) studied 75 men undergoing infertility screening and 75 normal controls. Ashwagandha treatment (5 g root powder daily for 3 months) improved semen quality in infertile men: increased sperm concentration, motility, and semen volume, with improved serum hormone profiles (increased testosterone and luteinizing hormone, decreased follicle-stimulating hormone and prolactin). Also reduced oxidative stress markers in seminal plasma. The traditional Vajikara (aphrodisiac/fertility-enhancing) indication is supported by this and other studies.
[14]Stress-related sexual dysfunction
Traditional Ayurvedic use as Vajikara for stress-related loss of libido and sexual function in both men and women. The mechanism likely involves cortisol reduction, testosterone support, and general vitality enhancement rather than direct phosphodiesterase inhibition or other pharmaceutical-type mechanisms.
[1, 15]Cardiovascular System
Cardiorespiratory endurance
Choudhary et al. (2015) RCT showed significant improvement in VO2 max (maximal oxygen consumption) with ashwagandha root extract in healthy athletic adults. The improvement in cardiorespiratory fitness may be mediated by adaptogenic effects on energy metabolism and oxygen utilization. This indication is primarily relevant in the context of physical performance enhancement.
[12]Energetics
Temperature
warm
Moisture
slightly dry
Taste
Tissue States
cold/depression, wind/tension, atrophy/deficiency
In Ayurvedic energetics: Rasa (taste) is tikta (bitter), kashaya (astringent), and madhura (sweet). Virya (potency) is ushna (warming). Vipaka (post-digestive effect) is madhura (sweet). Dosha effects: primarily reduces Vata and Kapha; may increase Pitta in excess due to warming quality. The sweet vipaka and post-digestive effect reflects its nourishing, building (brimhana) quality, distinguishing it from purely bitter herbs that tend to be depleting. Guna (qualities): laghu (light) and snigdha (unctuous). In Western herbal energetics, the warming quality supports circulation and vitality in cold, depleted constitutions. The slightly drying quality is mild and offset by the sweet, nourishing post-digestive effect, making it generally well-tolerated across constitutions. Ashwagandha is specifically indicated for conditions of depletion, deficiency, nervous exhaustion, and stress-induced debility — conditions associated with Vata disturbance in Ayurveda and cold/depression and atrophy tissue states in Western vitalist tradition.
Traditional Uses
Ayurvedic medicine (classical)
- Rasayana (rejuvenation therapy): one of the most important Rasayana herbs for building ojas (vital essence), promoting longevity, and preventing disease
- Medhya Rasayana (intellect-promoting): used to enhance memory, learning, and cognitive function
- Balya (strength-promoting): given to build strength, muscle mass, and physical endurance; prescribed during convalescence
- Vajikara (aphrodisiac): used for male sexual debility, infertility, and loss of libido
- Nidrajnana (sleep-inducing): root powder with warm milk at bedtime for insomnia
- Treatment of Vata disorders including nervous exhaustion, anxiety, tremors, and neuromuscular conditions
- Treatment of Shwasa and Kasa (breathing difficulties and cough)
- Treatment of Shotha (inflammation and swelling)
- Given with ghee, warm milk, and sugar as an anabolic tonic for emaciation and debility
"Ashwagandha is described in the foundational Ayurvedic texts including the Charaka Samhita (c. 100 BCE-200 CE) and Sushruta Samhita (c. 600 BCE) as one of the most valued Rasayana herbs. Charaka specifically classifies it as a Balya (strength-promoting) and Vajikara (fertility-enhancing) herb. In the Ashtanga Hridayam, it is recommended for Vata diseases, emaciation, and as a general tonic. The classical preparation 'Ashwagandhadi Churna' (ashwagandha root powder compound) is a cornerstone Rasayana formulation prescribed for debility, nervous exhaustion, and reproductive weakness."
Unani (Greco-Arab) medicine
- Known as Asgand or Asgand Nagori
- Used as a general tonic and restorative for debility
- Treatment of joint pain and inflammatory conditions
- Treatment of nervous disorders and insomnia
- Applied as a poultice for swelling, boils, and skin disorders
"In the Unani medical tradition, ashwagandha (Asgand) is classified as having a hot and dry temperament (second degree). It is prescribed as a tonic for the elderly and debilitated, for nervous weakness, and for inflammatory conditions of the joints. Unani practitioners emphasize its warming, strengthening quality for conditions of cold temperament and weakness."
[1]
African traditional medicine
- Used in parts of East and South Africa where the plant grows natively
- Treatment of fever and inflammatory conditions
- Decoction of root for sexually transmitted infections
- Leaf poultice applied to wounds, boils, and abscesses
- General tonic for debility and wasting conditions
"In parts of Africa where Withania somnifera grows wild, traditional healers have independently recognized its medicinal properties. Uses vary by region but commonly include treatment of inflammatory conditions, fevers, and as a general tonic. In South Africa, the root decoction is used by traditional healers for various inflammatory and infectious conditions."
[1]
Siddha medicine (South India)
- Known as Amukkara or Amukkarang
- Used as a rejuvenative tonic (similar to Ayurvedic Rasayana concept)
- Treatment of rheumatic conditions and joint pain
- Treatment of nervous debility and insomnia
- Root paste applied externally for inflammatory swelling
"In the Siddha medical tradition of Tamil Nadu, ashwagandha (Amukkara) is used for indications overlapping with but distinct from Ayurvedic practice. Siddha practitioners emphasize its utility for rheumatic conditions and as a tonic for debility in the elderly. External application of root paste is a common Siddha practice for inflammatory swelling."
[1]
Modern Research
Stress reduction and cortisol — landmark RCT
Prospective, randomized, double-blind, placebo-controlled study of high-concentration full-spectrum ashwagandha root extract (KSM-66) in 64 subjects with a history of chronic stress, over 60 days.
Findings: The ashwagandha group (300 mg twice daily) showed significant reduction in scores on all stress-assessment scales: Perceived Stress Scale (PSS), General Health Questionnaire-28 (GHQ-28), and Depression Anxiety Stress Scale (DASS). Serum cortisol levels were substantially and significantly reduced in the ashwagandha group (−27.9% from baseline) compared to placebo (−7.9%; P = 0.0006). No serious adverse events were reported.
Limitations: Moderate sample size (n=64). Single preparation (KSM-66). Relatively short duration (60 days). Self-reported stress scales (though cortisol provides an objective biomarker). Industry-funded study.
[5]
Anxiety reduction — RCT with hormonal biomarkers
Randomized, double-blind, placebo-controlled study of ashwagandha extract (Shoden, 240 mg/day standardized to 35% withanolide glycosides) in 60 stressed but otherwise healthy adults over 60 days.
Findings: Significant reduction in Hamilton Anxiety Rating Scale (HAM-A) scores in the ashwagandha group vs. placebo (P < 0.05). Significant reduction in morning cortisol (P = 0.031) and DHEA-S (P = 0.004) in the ashwagandha group. Also showed significant improvements in sleep quality (assessed by questionnaire). Testosterone levels showed a greater increase in the ashwagandha group compared to placebo in males (but not females).
Limitations: Relatively small sample size (n=60). Single extract type (Shoden). Healthy adults with self-reported stress; may not generalize to clinical anxiety disorders. Short duration.
[6]
Systematic review of anxiolytic effects
Systematic review examining 5 human clinical trials (all RCTs) assessing the anxiolytic effects of ashwagandha in subjects with anxiety or stress.
Findings: All 5 studies reviewed showed that ashwagandha intervention resulted in greater score improvements (lower anxiety/stress scores) compared to placebo. The review concluded that ashwagandha produces beneficial anxiolytic effects in the context of stress and anxiety and that current evidence supports its use as an anxiolytic, though additional large-scale studies are needed.
Limitations: Limited number of studies (n=5) available at time of review. Heterogeneity in preparations, doses, and outcome measures. Most studies were small. The review was narrative rather than a formal meta-analysis. Quality of some included studies was moderate.
[10]
Muscle strength and recovery in resistance training
Randomized, double-blind, placebo-controlled study examining the effects of ashwagandha root extract (300 mg twice daily) on muscle strength and recovery in 57 young male subjects undergoing resistance training for 8 weeks.
Findings: The ashwagandha group demonstrated significantly greater increases in muscle strength on bench press (placebo: 26.4 kg increase; ashwagandha: 46.0 kg increase) and leg extension (placebo: 9.8 kg; ashwagandha: 14.5 kg). Significantly greater increases in muscle size (arm circumference). Significantly greater reduction in exercise-induced muscle damage as measured by serum creatine kinase. Significantly greater decrease in body fat percentage. Testosterone levels were significantly higher in the ashwagandha group (96.2 ng/dL increase) compared to placebo (18.0 ng/dL increase).
Limitations: Small sample size (n=57). Young male subjects only; results may not generalize to females or older adults. Short duration (8 weeks). Single dose and extract. The magnitude of strength differences is large and warrants replication. Industry-funded.
[7]
Sleep quality improvement
Prospective, randomized, double-blind, placebo-controlled study of ashwagandha root extract in 150 healthy subjects with self-reported sleep complaints, over 10 weeks.
Findings: Ashwagandha root extract significantly improved Pittsburgh Sleep Quality Index (PSQI) scores compared to placebo. Both doses tested (120 mg of a standardized extract and 300 mg of full-spectrum root extract) showed benefit. Sleep onset latency was reduced and sleep efficiency improved. Non-restorative sleep symptoms were significantly reduced. The effect was more pronounced in subjects classified as having insomnia (PSQI > 5) than in those with milder sleep complaints.
Limitations: Self-reported sleep outcomes (no polysomnography). Healthy volunteers with sleep complaints rather than clinically diagnosed insomnia. Two different preparations tested (standardized vs. full-spectrum), complicating dose comparison.
[8]
Safety and tolerability study
Prospective, open-label, non-randomized study evaluating the safety and tolerability of ashwagandha root aqueous extract in 18 healthy volunteers, with escalating doses over 30 days.
Findings: Ashwagandha root extract was well-tolerated at doses of 750 mg/day and 1,000 mg/day (divided doses). No serious adverse events were reported. Hematological and biochemical parameters (liver function, kidney function, blood glucose, lipid profile) remained within normal limits. Some beneficial trends observed: reduction in total cholesterol and triglycerides, increase in muscle strength parameters. Stool consistency changes (softening) were noted in some subjects.
Limitations: Open-label design without placebo control. Very small sample size (n=18). Short duration (30 days). Healthy volunteers only; does not address safety in disease states or with concomitant medications. Single preparation.
[9]
Cognitive enhancement and memory
Prospective, randomized, double-blind, placebo-controlled study of ashwagandha root extract (300 mg twice daily) in 50 adults with mild cognitive impairment, over 8 weeks.
Findings: Ashwagandha treatment resulted in significant improvements in immediate and general memory (Wechsler Memory Scale III), attention and information processing speed, and executive function compared to placebo. Significant improvements were also seen in the sustained attention-to-response task. The cognitive benefits were attributed to the antioxidant, neuroprotective, and anti-stress effects of the withanolides.
Limitations: Small sample size (n=50). Subjects with mild cognitive impairment; may not generalize to healthy populations or clinical dementia. Short duration (8 weeks). Single preparation and dose.
[12]
Thyroid function in subclinical hypothyroidism
Randomized, double-blind, placebo-controlled study of ashwagandha root extract (600 mg/day) in 50 subjects with elevated serum TSH (subclinical hypothyroidism) over 8 weeks.
Findings: Ashwagandha treatment significantly improved serum thyroid indices: TSH normalized toward reference range, serum T4 significantly increased (P < 0.05), and serum T3 significantly increased (P < 0.05) compared to placebo. The authors suggested ashwagandha may stimulate thyroid hormone production and may be a useful treatment option for subclinical hypothyroidism.
Limitations: Small sample size (n=50). Subclinical hypothyroidism only; unclear relevance to overt hypothyroidism. Short duration (8 weeks). The thyroid-stimulating effect is clinically important: it represents a potential contraindication in hyperthyroidism and requires consideration in patients on thyroid hormone replacement therapy. Mechanism of thyroid stimulation is not fully elucidated.
[11]
Immune cell activation — pilot study
Randomized, double-blind, placebo-controlled, crossover pilot study of ashwagandha whole root extract in healthy adult volunteers, examining effects on immune cell activation markers.
Findings: Ashwagandha treatment (6 mL extract twice daily for 96 hours) significantly increased CD4+ T-cell and CD56+ natural killer cell activity markers compared to placebo. Complement C4 levels also showed increase. The findings suggest ashwagandha can enhance activation of immune effector cells relevant to both adaptive and innate immunity.
Limitations: Pilot study with very small sample size. Short treatment duration (96 hours). Surrogate markers (immune cell activation) rather than clinical endpoints (infection rates). Crossover design with potential carryover. Dose and form (aqueous extract, 6 mL) differs from most commercial products.
[13]
Male fertility and semen quality
Clinical study of ashwagandha root powder (5 g/day for 3 months) in 75 infertile men undergoing evaluation, compared to 75 normal healthy fertile men.
Findings: Ashwagandha treatment improved semen quality parameters: significant increase in sperm concentration, semen volume, and sperm motility. Improved hormone profiles: increased testosterone and luteinizing hormone; decreased FSH and prolactin. Reduced oxidative stress markers in seminal plasma: reduced levels of reactive oxygen species and lipid peroxidation; increased antioxidant enzyme activity (SOD, catalase, glutathione). The treatment recovered seminal plasma antioxidant levels to near-normal values seen in fertile controls.
Limitations: Not a randomized placebo-controlled trial. Open-label design. High dose of crude root powder (5 g/day) vs. lower doses of standardized extracts used in other studies. Single-center study in India. Results may not generalize across populations.
[14]
Preparations & Dosage
capsule-powder
Strength: Crude root powder, typically 400-600 mg per capsule. 2-10 capsules daily depending on strength.
Dried ashwagandha root powder (churna) encapsulated in gelatin or vegetable capsules. Ensure product specifies root-only material and is from a reputable source with withanolide content verification. Root powder should be light brown to cream colored with the characteristic odor.
1-6 g of root powder daily, typically divided into 2-3 doses. Traditional Ayurvedic dose: 3-6 g of root churna per day. Lower doses (1-2 g) for mild adaptogenic support; higher doses (3-6 g) for therapeutic use in debility, insomnia, and reproductive indications.
Divided into 2-3 doses daily with meals. For sleep: take the last dose with warm milk before bedtime.
Traditional use supports long-term administration (months to years) as a Rasayana tonic. Clinical trials typically 8-12 weeks. Periodic reassessment advisable.
Not established in clinical trials. Traditional Ayurvedic use in children (reduced dose, e.g., 1-2 g with milk) under qualified practitioner guidance.
Root powder (churna) is the most traditional preparation form. In Ayurveda, ashwagandha churna is typically administered with an anupana (carrier substance) to enhance absorption and direct therapeutic action: warm milk (general tonic, sleep), ghee (nervous system, deep tissue nourishment), honey (Kapha conditions), or warm water (general use). The anupana is considered therapeutically important, not merely a vehicle. Commercial capsules bypass the anupana tradition but are convenient for compliance.
Standardized Extract
Strength: DER varies by product: KSM-66 approximately 10-15:1 (root only); Sensoril approximately 8-12:1 (root + leaf). Standardization targets: 2.5-35% withanolides depending on methodology (gravimetric vs. HPLC) and whether glycosides are included.
Commercially prepared concentrated root extracts standardized to withanolide content. Major branded extracts include KSM-66 (full-spectrum root extract, 5% withanolides by HPLC), Sensoril (root and leaf extract, standardized to withanolide glycosides and withaferin A), and Shoden (root and leaf extract, 35% withanolide glycosides). Follow manufacturer's specific dosing guidelines as concentration varies significantly.
KSM-66: 300-600 mg/day (5% withanolides). Sensoril: 125-250 mg/day (10% withanolide glycosides). Shoden: 120-240 mg/day (35% withanolide glycosides). Generic standardized extracts: 300-600 mg/day (standardized to 2.5-5% withanolides). Dose depends on extract concentration.
1-2 times daily, typically with meals. For sleep: take one dose with dinner or before bedtime.
Most clinical trials used 8-12 week durations. Longer-term use (6+ months) has limited but supportive safety data.
Not established. Not recommended without qualified practitioner guidance.
Standardized extracts are the basis of most modern clinical research and provide the most consistent dosing. IMPORTANT: withanolide percentages are not comparable across products due to different analytical methods (HPLC vs. gravimetric), different reference standards, and whether the measurement includes withanolide glycosides or only free withanolides. A product claiming '5% withanolides by HPLC' is not equivalent to one claiming '5% withanolides by gravimetry.' Root-only extracts (e.g., KSM-66) have a different withanolide profile than root-plus-leaf extracts (e.g., Sensoril), with leaf-containing extracts having higher withaferin A content.
Decoction
Strength: 3-6 g dried root per 200 mL liquid (water, milk, or combination)
Add 3-6 g of dried, cut/sifted ashwagandha root to 200-250 mL of water and milk (equal parts or 2:1 milk to water). Simmer gently for 15-20 minutes. Strain. Add honey, ghee, or raw sugar (jaggery) to taste. The traditional Ayurvedic preparation 'Ashwagandha Ksheerapaka' involves simmering the root in milk until the milk is reduced.
One cup (200 mL) 1-2 times daily. For sleep: one cup before bedtime.
1-2 times daily.
May be used long-term as a tonic.
Half cup under practitioner guidance for children over 5 years.
The milk decoction (Ksheerapaka) is the most traditional Ayurvedic method of ashwagandha administration. Milk serves as both an anupana (carrier) and a synergistic medium — the fat content of milk may enhance absorption of the lipophilic withanolides. The warming, nourishing quality of the milk decoction is particularly suited to the Vata-pacifying and Brimhana (tissue-building) indications. This form is preferred in traditional practice for insomnia, debility, and convalescence.
Tincture
Strength: 1:5, 45-60% ethanol (dried root)
Macerate dried ashwagandha root in ethanol-water menstruum. Typical ratio 1:5 in 45-60% ethanol for dried root. Macerate for 4-6 weeks, shaking regularly. Press and filter.
2-4 mL, 2-3 times daily.
2-3 times daily. For sleep: single dose before bedtime.
May be used for extended periods. Reassess after 8-12 weeks.
Not recommended for children without practitioner guidance.
Tincture is not a traditional Ayurvedic preparation form but is common in Western herbal practice. The ethanol menstruum extracts a broad range of withanolides and alkaloids. Lower alcohol percentage (45%) may be adequate for ashwagandha compared to some other herbs, as withanolides have moderate water solubility. Tincture allows for flexible dosing and easy combination with other herbal tinctures in formula.
[16]
Glycerite
Strength: 1:5, 60% glycerin
Macerate dried ashwagandha root in vegetable glycerin-water mixture (typically 60-75% glycerin). Alcohol-free alternative suitable for those avoiding ethanol.
3-5 mL, 2-3 times daily.
2-3 times daily.
May be used for extended periods.
1-2 mL under practitioner guidance.
Glycerite is an alcohol-free option. Glycerin is less effective than ethanol at extracting the full range of withanolides but provides a palatable, sweet-tasting preparation. Suitable when alcohol is contraindicated (children under practitioner guidance, those avoiding alcohol for religious or health reasons, recovering alcoholics). The sweet taste of glycerin complements ashwagandha's sweet vipaka in Ayurvedic terms.
[16]
Infusion (Tea)
Strength: 1-2 g dried root per 200 mL water
Pour 200 mL of boiling water over 1-2 g of dried, powdered ashwagandha root. Cover and steep for 15 minutes. Strain. May add honey or warm milk to taste.
One cup 1-2 times daily.
1-2 times daily.
Ongoing as a daily tonic.
Not commonly used. Half cup under practitioner guidance.
Simple hot water infusion is less commonly used than decoction or milk preparations for ashwagandha, as the harder root material benefits from longer simmering to fully extract constituents. An infusion provides a lighter extract adequate for mild adaptogenic support. The taste is somewhat bitter and earthy; combining with chai spices (cinnamon, cardamom, ginger) or honey improves palatability.
[1]
Safety & Interactions
Class 1
Can be safely consumed when used appropriately (AHPA Botanical Safety Handbook)
Contraindications
Ashwagandha has demonstrated thyroid-stimulating activity, significantly increasing T3 and T4 levels in clinical trials (Sharma et al. 2018). In patients with hyperthyroidism or Graves' disease, further elevation of thyroid hormones could worsen symptoms including tachycardia, tremor, weight loss, and anxiety, and could precipitate thyroid storm in severe cases. This is the most clinically significant contraindication.
Patients with documented allergy to ashwagandha or strong sensitivity to Solanaceae (nightshade) plants should avoid use. While cross-reactivity within the family is not well-documented, caution is warranted.
Due to its immunomodulating and immunostimulating properties, ashwagandha may theoretically exacerbate autoimmune conditions including rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, and Hashimoto's thyroiditis. While the immunomodulating action is bidirectional (and could theoretically downregulate overactive immunity), the clinical evidence is insufficient to guarantee safety in active autoimmune disease. Use only under qualified practitioner supervision with monitoring.
Due to potential effects on the CNS (mild sedation), thyroid function, and theoretical interactions with anesthetic agents, discontinuation before elective surgery is recommended as a precautionary measure.
Drug Interactions
| Drug / Class | Severity | Mechanism |
|---|---|---|
| Levothyroxine (Synthroid) and other thyroid hormones (Thyroid hormones) | moderate | Ashwagandha may independently increase T3 and T4 production (Sharma et al. 2018), potentially causing additive thyroid hormone elevation when combined with exogenous thyroid hormone replacement. |
| Benzodiazepines (diazepam, lorazepam, alprazolam, etc.) and other anxiolytics (Anxiolytics / CNS depressants) | moderate | Ashwagandha has GABAergic and sedative activity that may be additive with benzodiazepines and other anxiolytics, potentially causing excessive sedation. |
| Immunosuppressants (cyclosporine, tacrolimus, azathioprine, corticosteroids) (Immunosuppressants) | moderate | Ashwagandha's immunostimulating properties (enhancement of NK cell activity, CD4+ T-cell activation, macrophage function) could theoretically counteract the effects of immunosuppressive medications. |
| Sedative-hypnotics (zolpidem, zaleplon, eszopiclone) and barbiturates (Sedative-hypnotics) | moderate | Potential additive CNS depression through overlapping GABAergic and sedative mechanisms. |
| Antidiabetic medications (insulin, metformin, sulfonylureas) (Hypoglycemic agents) | minor | Ashwagandha may lower blood glucose levels based on some preclinical and limited clinical evidence, potentially causing additive hypoglycemia. |
| Antihypertensive medications (Antihypertensives) | minor | Ashwagandha may have mild blood pressure-lowering effects secondary to its calming, anxiolytic, and stress-reducing properties. |
Pregnancy & Lactation
Pregnancy
possibly unsafe
Lactation
insufficient data
PREGNANCY: Ashwagandha is classified as possibly unsafe during pregnancy. Animal studies have shown abortifacient (pregnancy-terminating) activity at high doses — withaferin A has demonstrated embryotoxic effects in animal models. The WHO monograph advises against use during pregnancy. The AHPA Botanical Safety Handbook classifies ashwagandha as Class 2b (not to be used during pregnancy). While traditional Ayurvedic practice occasionally used low doses during pregnancy for specific indications under expert guidance, the modern consensus based on available preclinical data is to avoid use during pregnancy as a precautionary measure. LACTATION: Insufficient data to establish safety during breastfeeding. No human lactation studies are available. Traditional Ayurvedic practice considered ashwagandha safe during lactation and even used it as a galactagogue in some traditions, but modern evidence is inadequate to confirm safety. Avoid use during lactation unless the benefit outweighs the theoretical risk, and only under qualified practitioner supervision.
Adverse Effects
References
Monograph Sources
- [1] World Health Organization. WHO Monographs on Selected Medicinal Plants, Volume 4: Radix Withaniae. World Health Organization, Geneva (2009) : 373-391
- [2] Gardner Z, McGuffin M (eds.). American Herbal Products Association's Botanical Safety Handbook, Second Edition: Withania somnifera. CRC Press, Boca Raton (2013) : 907-909
- [3] Ministry of Health and Family Welfare, Government of India. The Ayurvedic Pharmacopoeia of India, Part I, Volume 1: Ashwagandha (Root). Government of India, New Delhi (2001) : 14-15
- [4] United States Pharmacopeial Convention. Ashwagandha Root and Ashwagandha Root Powder — USP Dietary Supplement Monograph. United States Pharmacopeia (USP) (2020)
Clinical Studies
- [5] 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 : 255-262 . DOI: 10.4103/0253-7176.106022 . PMID: 23439798
- [6] 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 : e17186 . DOI: 10.1097/MD.0000000000017186 . PMID: 32021735
- [7] 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 . DOI: 10.1186/s12970-015-0104-9 . PMID: 26609282
- [8] 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 : e5797 . DOI: 10.7759/cureus.5797 . PMID: 31728244
- [9] Raut AA, Rege NN, Tadvi FM, Solanki PV, Kene KR, Shirolkar SG, Pandey SN, Vaidya RA, Vaidya AB. Exploratory study to evaluate tolerability, safety, and activity of Ashwagandha (Withania somnifera) in healthy volunteers. J Ayurveda Integr Med (2012) ; 3 : 111-114 . DOI: 10.4103/0975-9476.100168 . PMID: 22308094
- [10] 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 : 901-908 . DOI: 10.1089/acm.2014.0177 . PMID: 24046237
- [11] 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 : 243-248 . DOI: 10.1089/acm.2017.0183 . PMID: 28829155
- [12] Choudhary D, Bhatt S, Banerjee S. Efficacy and safety of ashwagandha (Withania somnifera (Linn.) Dunal) root extract in improving memory and cognitive functions. J Diet Suppl (2017) ; 14 : 599-612 . DOI: 10.1080/19390211.2017.1284970 . PMID: 28471731
- [13] Mikolai J, Erlandsen A, Murison A, Brown KA, Gregory WL, Raman-Caplan P, Zwickey HL. In vivo effects of ashwagandha (Withania somnifera) extract on the activation of lymphocytes. J Altern Complement Med (2009) ; 15 : 423-430 . DOI: 10.1089/acm.2008.0215 . PMID: 19388865
- [14] Ahmad MK, Mahdi AA, Shukla KK, Islam N, Rajender S, Madhukar D, Shankhwar SN, Ahmad S. Withania somnifera improves semen quality by regulating reproductive hormone levels and oxidative stress in seminal plasma of infertile males. Fertil Steril (2010) ; 94 : 989-996 . DOI: 10.1016/j.fertnstert.2009.04.046 . PMID: 19501822
Traditional Texts
- [15] 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 : 208-213 . DOI: 10.4314/ajtcam.v8i5S.9 . PMID: 22754076
- [16] Hoffmann D. Medical Herbalism: The Science and Practice of Herbal Medicine. Healing Arts Press, Rochester, VT (2003) : 588-589
- [17] Bone K, Mills S. Principles and Practice of Phytotherapy: Modern Herbal Medicine, Second Edition. Churchill Livingstone/Elsevier, Edinburgh (2013) : 953-961
- [18] Winston D, Maimes S. Adaptogens: Herbs for Strength, Stamina, and Stress Relief. Healing Arts Press, Rochester, VT (2007) : 140-148
Pharmacopeias & Reviews
- [19] Panossian A, Wikman G. Effects of adaptogens on the central nervous system and the molecular mechanisms associated with their stress-protective activity. Pharmaceuticals (Basel) (2010) ; 3 : 188-224 . DOI: 10.3390/ph3010188 . PMID: 27713248
- [20] Dar NJ, Hamid A, Ahmad M. Pharmacologic overview of Withania somnifera, the Indian ginseng. Cell Mol Life Sci (2015) ; 72 : 4445-4460 . DOI: 10.1007/s00018-015-2012-1 . PMID: 26306935
- [21] 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 : e6466 . DOI: 10.7759/cureus.6466 . PMID: 31950516
- [22] National Center for Complementary and Integrative Health (NCCIH). Ashwagandha. NCCIH, National Institutes of Health (2023)
- [23] Examine.com Research Team. Ashwagandha — Scientific Review on Usage, Dosage, Side Effects. Examine.com (2024)
Last updated: 2026-02-26 | Status: review