Ashwagandha: Benefits, Forms, Dosing, and Side Effects

Ashwagandha (Withania somnifera) is one of the most extensively studied adaptogenic herbs, with a robust evidence base from multiple meta-analyses supporting benefits for anxiety, stress, cortisol reduction, sleep, testosterone in men, cognitive function, and physical performance. The World Federation of Societies of Biological Psychiatry (WFSBP) and the Canadian Network for Mood and Anxiety Treatments (CANMAT) provisionally recommend it for generalized anxiety disorder. However, most individual trials are small and short-term, and serious safety concerns have emerged -- particularly liver injury and thyrotoxicosis. The withanolide content and standardization of the extract matter significantly for efficacy, with extracts standardized to at least 5% withanolides showing the most consistent benefits.

Table of Contents

• Overview
• Forms and Bioavailability
• Evidence for Benefits
• Recommended Dosing
• Safety and Side Effects
• Drug Interactions
• Dietary Sources
• References

Overview

Ashwagandha (Withania somnifera) is an evergreen shrub cultivated in tropical and subtropical areas of Asia, Africa, and Europe. The plant's roots have been used for centuries in Ayurvedic and Unani medicine as an adaptogen -- loosely defined as a compound that increases the ability to resist, adapt to, or become resilient against biological, physical, or chemical stressors [1][2][3]. Ashwagandha is also known as "Indian ginseng" (despite no botanical relation to ginseng) and "winter cherry," though it should not be confused with Physalis alkekengi, which shares this common name [4]. The species name somnifera derives from Latin for "sleep-inducing," signifying another traditional use [5].

The root contains a class of steroidal lactones called withanolides, believed to be responsible for many of ashwagandha's pharmacological effects [1][4][6]. Key withanolides include withaferin A and withanolide D [7]. Alkaloids (including withanine and somniferine) and sitoindosides are also present [7]. Withanolide concentrations typically range from 0.001% to 0.5% of dry weight in both roots and leaves, though withaferin A can reach up to 1.6% in leaves [8]. Preclinical research suggests that non-withanolide components may also contribute to ashwagandha's effects [5][9].

The chemical composition of root and leaf differs significantly. Ashwagandha leaf contains substantially more withanone (19 vs. 3 mg/g) and withaferin A (22.31 vs. 0.92 mg/g) than the root [10][11]. This distinction has safety implications: laboratory research suggests withanone may cause DNA damage and liver injury if used in excess or by people with low glutathione levels, and withaferin A has also raised concerns about potential liver effects [10][11]. Most commercial supplements contain root extracts, though some include both root and leaf.

A comprehensive meta-analysis of 23 randomized controlled trials involving 1,706 participants found that ashwagandha supplementation significantly lowered cortisol levels (SMD −1.18, p < 0.04), increased testosterone in men (mean difference 57.43 ng/dL, with no significant increase in women), and reduced anxiety and stress symptoms [12][13]. Among adaptogens, ashwagandha has the most robust evidence base from meta-analyses, particularly compared to Rhodiola rosea, for reducing perceived stress, anxiety, depression, and serum cortisol [12][14][15].

The World Federation of Societies of Biological Psychiatry (WFSBP) and the Canadian Network for Mood and Anxiety Treatments (CANMAT) provisionally recommend ashwagandha root extract (300–600 mg/day, standardized to 5% withanolides) for generalized anxiety disorder, though they note more data are needed for a stronger recommendation [16].

Forms and Bioavailability

Branded Extracts

The clinical literature uses several standardized ashwagandha extracts, each differing in plant parts used, withanolide content, and studied effects.

Extract	Manufacturer	Plant Part	Standardization	Typical Dose	Primary Clinical Uses
KSM-66	Ixoreal Biomed	Root only	≥5% withanolides	300–600 mg/day	Stress, anxiety, sleep, cognition, physical performance, testosterone, fertility
Sensoril	Natreon (Kerry)	Root + leaf	≥10% withanolide glycosides	125–500 mg/day	Stress, anxiety, cognition, physical performance, joint pain
Shoden	Arjuna Natural	Root + leaf	35% withanolide glycosides	60–240 mg/day	Anxiety, sleep, cortisol reduction
NooGandha	Specnova	Root + leaf	3.5–4% withanolides	225–400 mg/day	Cognitive function, stress
Witholytin	Verdure Sciences	Root	1.5% withanolides	200–400 mg/day	Fatigue, stress

Key Differences

KSM-66 is a full-spectrum root-only extract, aligned with traditional Ayurvedic use. It minimizes withaferin A content (a cytotoxic withanolide more concentrated in leaves). It is the most extensively studied branded extract, with trials covering stress, anxiety, sleep, cognition, physical performance, testosterone, and fertility outcomes [4][17][18][19].

Sensoril includes both root and leaf, resulting in higher withanolide potency (≥10%), allowing lower effective doses (125–500 mg/day). It tends toward more calming and sedative effects compared to KSM-66, and may be preferred for nighttime use, relaxation, and sleep [20][21]. However, the inclusion of leaf raises the theoretical concern of higher withaferin A and withanone content.

Shoden is enriched in withanolide glycosides (35%), a form with enhanced bioavailability. A pharmacokinetic study found that Shoden achieved approximately 18 times the withanolide blood levels of a regular 2.5% extract calculated to deliver equivalent withanolides, when both were taken on an empty stomach with water only [22]. However, an employee of the manufacturer was among the study authors, and it is unknown how results would differ with food [4][22].

NooGandha is positioned as a nootropic-adaptogen hybrid, emphasizing cognitive benefits without sedation. Independent clinical data are more limited compared to KSM-66 or Sensoril [23][24].

Withanolide Content and Quality

The United States Pharmacopeia (USP) requires ashwagandha extracts to contain no less than 2.5% total withanolides. Products should list withanolide content as a percentage or milligram amount. Root powder should contain a minimum of 0.3% withanolides; extracts should contain at least 1.5% [4].

Testing of 25 ashwagandha supplements purchased from Amazon found that 60% failed to contain expected withanolide amounts based on USP standards. Among 16 products that declared withanolide percentages, 9 (56%) contained 69% to 99% less than labeled. All products that passed testing claimed ≤2.5% withanolides, while 8 of the 9 failures claimed 5% to 35% [25].

Pharmacokinetics

Active withanolide compounds have half-lives of approximately 2–10 hours, with averages commonly reported as 6–8 hours. Complete elimination takes approximately 10–50 hours (4–5 half-lives) after a single dose. Absorption is rapid, with peak plasma concentrations typically reached within 1–2 hours. Acute effects (mild relaxation, stress relief) generally last 6–12 hours, while cumulative therapeutic benefits (cortisol reduction, anxiety relief, improved sleep) require consistent daily use over 4–12 weeks [26].

Evidence for Benefits

Anxiety

Clinical evidence consistently supports ashwagandha for reducing anxiety symptoms. Multiple meta-analyses converge on significant anxiolytic effects, particularly at doses of 300–600 mg/day of standardized root extract.

Meta-analyses: A 2024 meta-analysis of 9 RCTs (n=558) found significant reductions in the Perceived Stress Scale (MD = −4.72, 95% CI −8.45 to −0.99), Hamilton Anxiety Scale (MD = −2.19, 95% CI −3.83 to −0.55), and serum cortisol levels (MD = −2.58, 95% CI −4.99 to −0.16) compared to placebo [27]. A 2022 meta-analysis of 12 RCTs (n=1,002) reported significant reductions in anxiety (SMD −1.55, 95% CI −2.37 to −0.74) and stress (SMD −1.75, 95% CI −2.29 to −1.22), with favorable dose-response effects particularly at 300–600 mg/day [28]. A 2026 dose-response meta-analysis of 22 RCTs (n=1,391) found significant reductions in anxiety (SMD = −6.87; 95% CI: −8.77 to −4.97), stress (SMD = −5.88), and depression (SMD = −5.68), with dose-dependent effects at 240–1,250 mg/day [29]. A 2021 systematic review of 7 studies (n=491) found ashwagandha significantly reduced stress and anxiety, with benefits appearing greater at 500–600 mg/day [9].

Individual trials: A double-blind study of 75 adults with moderate to severe anxiety found that 300 mg of ashwagandha root extract (1.5% withanolides) twice daily plus a multivitamin for 12 weeks dramatically reduced anxiety and significantly improved fatigue, motivation, and concentration compared to psychotherapy plus placebo [30]. A study in 60 adults with mild anxiety found that 240 mg/day of Shoden extract (84 mg withanolide glycosides) for 2 months decreased anxiety by 4.2 vs. 2.5 points and reduced morning cortisol by 23% vs. no change [31]. A study of 60 adults with generalized anxiety disorder found that just 60 mg/day of Shoden for 60 days reduced anxiety by 59% on the HAM-A scale (vs. 0.83% increase for placebo), stress by 48%, and morning cortisol by 65% [32]. A study of adults with GAD found 500–3,000 mg/day for 6 weeks significantly improved anxiety vs. placebo [33]. A 2019 RCT (n=60) found 240 mg/day for 60 days reduced HAM-A scores significantly (P = 0.040) [34].

A study of 130 healthy adults (ages 20–55) with self-reported stress found that sustained-release ashwagandha (Prolanza, 300 mg containing 15 mg withanolides) daily for 90 days improved stress, sleep quality, cortisol, well-being, memory, and focus vs. placebo [35]. A study of 54 adults found 500 mg root extract (2.5% withanolides) plus 5 mg piperine daily for 60 days reduced stress and anxiety, improved quality of life, multitasking, and concentration [36]. At the University of Colorado, 60 students taking 700 mg/day for 30 days reported increased well-being, calm, energy, mental clarity, and more manageable stress vs. placebo [37][38].

Stress and Cortisol

A study in 58 healthy adults found KSM-66 at 300 mg twice daily for 2 months produced slightly greater reductions in perceived stress (−8.8 vs. −6 points) and modestly decreased cortisol (−5.5 mcg/dL vs. +0.63 mcg/dL) vs. placebo. A lower dose (125 mg twice daily) was not effective [17]. A study of 98 adults with chronic stress found Sensoril at 250 mg or 500 mg daily for 8 weeks reduced stress by 13.65 and 15.63 points (vs. 6.46 for placebo). A 125 mg dose was not effective [20].

Studies with lower withanolide standardization have not shown significant stress benefits. Witholytin (1.5% withanolides, 400 mg/day) for 3 months did not reduce stress in 111 overweight adults, though it slightly decreased fatigue [39]. NooGandha (3.5–4% withanolides) at 225–400 mg/day for 30 days did not reduce stress in one study [23]. These findings suggest extracts standardized to at least 5% withanolides may be necessary for consistent stress benefits [4].

The mechanism operates through adaptogenic actions on the hypothalamic-pituitary-adrenal (HPA) axis. Preclinical studies demonstrate GABAergic mechanisms, including GABA-A receptor agonism and strong GABA-rho receptor agonism (approximately 27 times greater sensitivity than GABA-A), enhancing inhibitory neurotransmission and dampening cortisol secretion [7][40].

Sleep

Meta-analysis: A 2021 systematic review of 5 RCTs (n=372) found ashwagandha had a small but significant effect on sleep quality. Sleep onset latency: effect size −0.53 (95% CI −0.77 to −0.29), I² = 0%. Sleep efficiency improved (SMD −0.68, 95% CI −1.07 to −0.29). In insomniacs: SMD −0.84 (95% CI −1.10 to −0.58). Benefits were more prominent at ≥600 mg/day and ≥8 weeks duration [41][42].

Individual trials: In 58 adults with insomnia, KSM-66 at 300 mg twice daily for 10 weeks decreased sleep onset by 12.62 vs. 8 minutes with placebo [43]. In 73 adults (half with insomnia), the same dose for 8 weeks reduced onset by 14–15 minutes in insomniacs (vs. 3–5 for placebo) and increased sleep time by 37 minutes (insomniacs) and 9 minutes (non-insomniacs) [5][44]. Shoden (120 mg/day, 42 mg withanolides) for 6 weeks improved self-reported sleep quality by 72% vs. 29% for placebo in 150 healthy adults, with objective actigraphy showing 10 vs. 12 minutes onset latency [45]. In 58 college students, 700 mg/day for 30 days modestly improved restorative sleep but did not reduce stress [46].

Cognitive Function

Evidence is mixed, with benefits generally seen at higher withanolide doses (≥30 mg/day) and longer durations (≥8 weeks). Sensoril at 1,000 mg/day (≥100 mg withanolides) for 12 days significantly improved cognitive performance and reaction times in healthy men [47]. KSM-66 at 600 mg/day (30 mg withanolides) for 8 weeks improved memory, executive function, sustained attention, and information processing speed in adults with mild cognitive impairment -- but most improvements required the full 8 weeks [48]. However, a study of 114 adults found the same dosage did not improve spatial memory or processing speed, though episodic memory and attention improved on some measures [49].

NooGandha at 225 mg/day for 1 month did not improve cognitive function in 59 healthy young adults [24]. Acute ingestion of 400 mg improved executive function, attention, working memory, and reaction times [50]. Repeated supplementation at 225 mg/day for 30 days improved memory, attention, vigilance, and executive function [51]. A systematic review concluded ashwagandha improved cognitive tasks, executive function, attention, and reaction time in most studies [52].

Mechanistically, ashwagandha inhibits beta-amyloid plaque formation, enhances acetylcholine levels via increased choline acetyltransferase activity, and modulates serotonin and GABA receptors [53][54][55].

Testosterone and Male Reproductive Health

Ashwagandha has gender-specific effects on testosterone. The 2026 meta-analysis of 23 RCTs (n=1,706) found significant increases in men (mean difference 57.43 ng/dL) with no significant increase in women (5.09 ng/dL) [12].

In 46 oligospermic infertile men, 675 mg/day (33.75 mg withanolides) for 90 days increased testosterone by 17%, sperm count by 167%, semen volume by 53%, and motility by 57% [56]. In 57 men undergoing resistance training, KSM-66 at 600 mg/day for 8 weeks increased testosterone by ~15%, with gains in strength, muscle size, and reduced body fat [57]. A crossover study in overweight men aged 40–70 found Shoden (600 mg/day, 21 mg withanolide glycosides) for 8 weeks produced a 14.7% greater testosterone increase vs. placebo, but no differences in sexual well-being, vigor, or fatigue [58].

In healthy men (mean age 39), KSM-66 at 600 mg/day for 8 weeks did not change total or free testosterone but increased sexual desire (+14.26 points), erectile function (+15.11 points), semen volume (+39%), sperm motility (+16%), concentration (+32%), and total count (+38%) vs. placebo [59]. A 12-month safety study (n=191) showed KSM-66 at 600 mg/day caused small but significant increases in total testosterone (+6.1%) and free testosterone (+7.2%) in men [60].

Sexual Function in Women

In 50 women (ages 21–50) with low sexual desire or arousal, KSM-66 at 300 mg twice daily for 2 months significantly improved overall sexual function, arousal, lubrication, and satisfaction vs. placebo, though sexual desire did not significantly improve [61].

Peri- and Postmenopausal Symptoms

In 123 postmenopausal women (mean age 51), Sensoril at 125 mg or 250 mg twice daily for 6 months improved quality of life, bone resorption biomarkers, and (at higher dose) lumbar spine bone mineral density vs. placebo [62]. In 91 perimenopausal women, KSM-66 at 600 mg/day for 8 weeks slightly reduced symptom severity (−3.37 vs. −1.16 points on a 44-point scale), reduced hot flashes by ~1/day, increased estradiol, and decreased FSH [63]. In 60 perimenopausal women, KSM-66 at 600 mg/day for 8 weeks improved quality of life by ~12 points and reduced stress by ~46%, though hot flash frequency did not significantly decrease [64].

Physical Performance

Results are mixed, with more consistent benefits in untrained individuals. In 40 healthy young adults, 500 mg/day for 8 weeks increased VO2 max, velocity, and leg strength [65]. Sensoril at 500 mg/day (≥50 mg withanolides) for 3 months increased strength in 38 recreationally active young men [66]. KSM-66 at 600 mg/day for 2 months modestly improved VO2 max and recovery in 50 athletic adults [67]. The same dose for 8 weeks increased muscle strength and mass, reduced body fat, and decreased creatine kinase in 57 men undergoing resistance training [57].

A 2026 RCT in 56 semi-professional athletes found KSM-66 at 600 mg/day for 42 days stabilized stress biomarkers, improved recovery in females, and enhanced power and pull-ups in males, but testosterone did not change [68]. However, 30 female professional soccer players showed no significant improvements in power, strength, or fatigue on KSM-66 at 600 mg/day for 4 weeks [69]. A 2021 meta-analysis of 12 RCTs found small-to-moderate effects more pronounced in untrained individuals [70].

Body Weight and Metabolism

A 2016 study in chronically stressed adults found 300 mg twice daily for 8 weeks reduced body weight, BMI, and cortisol vs. placebo, with improved stress and food cravings [71]. Systematic reviews confirm body composition improvements when combined with resistance exercise, with typical fat loss of 1–3% over 8–12 weeks, more pronounced in stressed or overweight individuals [70].

Anti-inflammatory Effects and Joint Pain

In people with knee osteoarthritis, Sensoril at 250 mg or 150 mg twice daily for 12 weeks significantly reduced pain, stiffness, and disability, with the higher dose showing efficacy at 4 weeks. No adverse effects occurred, though 20% of the higher-dose group experienced nausea [72].

Thyroid Function

In 50 adults with subclinical hypothyroidism, KSM-66 at 600 mg/day for 8 weeks decreased TSH by 1.85 mIU/L and increased T3 and T4 vs. placebo [73]. Three adult men taking 500 mg/day of a root and leaf extract for 8 weeks showed small T4 increases [74]. The 12-month safety study found T3 increased from 123.14 to 132.25 ng/dL (within normal range) [60]. These effects suggest ashwagandha may interact with thyroid medications and affect thyroid hormones in people without thyroid disease.

Schizophrenia

In 66 adults with worsening schizophrenia, Sensoril (250–500 mg twice daily, ≥100 mg withanolides) for 3 months reduced negative and general symptoms vs. placebo, but did not improve hallucinations or delusions. Sleepiness, GI discomfort, and loose stools were more common [75].

Adjunctive Use in Psychiatric Conditions

An OCD trial found ashwagandha (120 mg/day) added to SSRIs improved symptoms over 6 weeks with no adverse events. In MDD patients, sertraline plus ashwagandha (250 mg twice daily) prevented liver enzyme elevations seen with sertraline alone. Schizophrenia secondary analyses showed medium effect sizes for depression and anxiety reduction [76].

Recommended Dosing

Dosing by Indication

Indication	Extract Dose	Withanolide Content	Duration	Evidence
Generalized anxiety disorder	300–600 mg/day root extract (5% withanolides)	15–30 mg/day	8–12 weeks	WFSBP/CANMAT provisional recommendation [16]
Stress and cortisol reduction	300–600 mg/day root extract	≥15 mg/day	8–12 weeks	Multiple positive RCTs and meta-analyses
Sleep improvement	300–600 mg/day root extract; or 120 mg Shoden	15–42 mg/day	6–12 weeks	Multiple positive RCTs; ≥600 mg and ≥8 weeks optimal [42]
Cognitive function	600–1,000 mg/day extract	30–100 mg/day	8–12 weeks	Mixed; higher withanolide doses necessary
Testosterone (men)	300–600 mg/day root extract	15–34 mg/day	8–12 weeks	Meta-analysis-supported
Male fertility	600–675 mg/day root extract	30–34 mg/day	8–12 weeks	Multiple positive RCTs
Physical performance	300–600 mg/day root extract	15–50 mg/day	8–12 weeks	Better for untrained individuals
Menopausal symptoms	250–600 mg/day root extract	25–30 mg/day	8 weeks–6 months	Multiple positive RCTs
Joint pain (osteoarthritis)	250–500 mg/day Sensoril	≥25–50 mg/day	12 weeks	One positive RCT

Practical Dosing Guidance

Starting dose: Begin with 250–300 mg/day and monitor response for 1–2 weeks before increasing [77].

Extract vs. root powder: Trials using root powder (not extract) typically use 3,000–6,000 mg/day [77][78]. The WFSBP/CANMAT recommendation applies specifically to extracts standardized to 5% withanolides.

Withanolide minimum: Look for products providing at least 6 mg withanolides per serving. Extracts standardized to ≥5% withanolides have the most consistent evidence. Studies using low standardization (≤1.5%) have generally not shown significant benefits [4][39].

Timing: No strong evidence supports a specific time of day. For sleep, take 1–2 hours before bed. For daytime stress management, morning or split dosing is commonly used. Taking with food may reduce GI discomfort [77].

Duration: Most clinical benefits emerge after 4–8 weeks. Long-term safety data beyond 3 months are limited, with one 12-month study showing good tolerability [60].

Safety and Side Effects

General Tolerability

Ashwagandha appears well tolerated for short-term use (up to ~3 months). Common side effects are mild: stomach upset, loose stools, nausea, drowsiness, and headache [9][60][75][79]. Some studies report somnolence rates up to 21% [80]. Long-term safety beyond 3 months is not well established.

Liver Injury

Rare but serious cases of liver injury warrant caution. Five cases (ages 21–62) taking 450–1,350 mg/day for 1 week to 4 months developed jaundice, pruritus, nausea, lethargy, and hyperbilirubinemia, resolving after stopping [81][82]. Three Iceland cases (2017–2018) involved NOW brand ashwagandha; two US cases included Nature's Way. Symptoms appeared 2–12 weeks after starting and resolved in 1–6 months [81].

A 40-year-old man developed jaundice 20 days after starting NOW brand (450 mg/day) despite using another brand for a year without issue [83]. A 39-year-old woman developed acute cholestatic hepatitis from 154 mg every other day for 6 weeks, with the pattern suggesting immune-related response [84]. A review of 8 Indian cases found 5 of 8 occurred in people with chronic liver disease; 3 of those 5 experienced liver failure and died [85]. A 2017 Japanese case involved liver dysfunction in a 20-year-old taking ashwagandha with multiple antianxiety drugs [86].

Leaf vs. root: Ashwagandha leaf contains more withanone (19 vs. 3 mg/g) and withaferin A (22.31 vs. 0.92 mg/g). A study of root extract containing 4.5% withaferin A at 1,600–4,800 mg/day elevated liver enzymes in 5 of 11 young cancer patients [10][11]. Until more is known, ashwagandha (particularly leaf-containing products) should not be used by people with liver disease.

Thyroid Effects

Ashwagandha can increase thyroid hormone levels. Cases of thyrotoxicosis include: a woman in the Netherlands taking capsules for several weeks [87]; a 62-year-old woman on 1,950 mg/day plus 15 mg black pepper for 2 months who developed thyroid enlargement, anxiety, weight loss, and anemia [88]; and a 47-year-old Japanese man who developed painless thyroiditis ~2 months after starting, normalizing 7 weeks after stopping [89].

Denmark banned ashwagandha in 2023 [90]. ANSES (France) recommended against use by pregnant/breastfeeding women and people with endocrine disorders [91]. The German BfR highlighted liver toxicity and hormonal risks [92].

Adrenal Effects

A 2022 case report described reversible adrenal insufficiency after 10 weeks (21.4 mg withanolides daily), with blunted cortisol response normalizing after 2 weeks of discontinuation [80].

Pregnancy and Reproductive Concerns

Most authorities advise against use during pregnancy due to reports of potential abortifacient effects [9][93][94], though the American Herbal Pharmacopoeia states there is no evidence ashwagandha root causes abortions [95].

Other Safety Concerns

• Nightshade allergy: Ashwagandha belongs to the Solanaceae family. People allergic to potato, eggplant, tomato, or peppers may react [4].
• Blood sugar: May lower blood sugar; use cautiously with diabetes or hypoglycemia [96].
• Blood pressure: May lower blood pressure; use cautiously with hypotension or antihypertensives [4].
• Cardiac rhythm: Dizziness, ventricular tachycardia, and fainting reported in 2 men (details lacking) [97].
• Skin reactions: Fixed drug eruption (penile) reported with 5 g root powder daily [98].
• Withdrawal effects: Isolated reports of anxiety, tachycardia, or insomnia after abrupt cessation of long-term use [80].
• Emotional blunting: Reports of brain fog and anhedonia appear online but are not established in clinical studies [80].

Drug Interactions

Medication Class	Interaction	Clinical Concern
Sedatives/Benzodiazepines	May potentiate sedation via GABAergic activity	Excessive drowsiness or respiratory depression [76][93]
Thyroid medications (levothyroxine)	Increases thyroid hormone production	Excessive levels; thyrotoxicosis risk [73][93]
Immunosuppressants (tacrolimus)	May stimulate immune activity	Reduced efficacy; kidney transplant rejection case [99]
SSRIs (escitalopram, sertraline)	May increase serotonin; possible CYP2D6/CYP3A4 inhibition	Serotonin syndrome risk; one case report [100][101]
Antihypertensives/Beta-blockers	May further lower blood pressure	Theoretical hypotension risk [4]
Antidiabetic medications	May lower blood sugar	Hypoglycemia risk [96]
Blood thinners (warfarin, clopidogrel)	Preliminary blood-thinning effects	Use with caution [102]
Anesthesia	Sedating effects	Discontinue prior to surgery [4]

Serotonin syndrome case: A 22-year-old woman developed serotonin syndrome (uncontrolled limb movement, fever, vomiting, pupil dilation, fast heart rate) 2 days after taking 600 mg ashwagandha (pill) plus 1,520 mg (tea) with escitalopram 10 mg daily. She recovered after discontinuing both [100].

Transplant rejection case: A 69-year-old kidney transplant recipient stable for 2 years developed acute rejection requiring kidney removal 2 weeks after starting ashwagandha [99].

Autoimmune trigger: A woman with celiac disease and systemic sclerosis developed optic neuritis ~2 weeks after starting ashwagandha, resolving with corticosteroids and cessation [103].

Dietary Sources

Ashwagandha is not a nutrient found in common foods. It is available exclusively as a supplement derived from the roots (and sometimes leaves) of the Withania somnifera plant. Traditional preparations include:

• Powdered root mixed with warm milk -- the classic Ayurvedic preparation
• Churna -- fine root powder, often combined with ghee or honey
• Root powder -- 3–6 g/day in traditional practice, divided into 2–3 doses
• Standardized extracts -- the most common modern form (capsules, tablets, powder)

Commercial forms include capsules, powders, tinctures, gummies, and topical preparations. Standardized root extracts (KSM-66, Sensoril, Shoden) are preferred for reliability and clinical evidence. Products should list withanolide content and ideally carry third-party testing verification [4][77]. The plant grows in dry, arid, and subtropical climates (primarily India, North Africa, Middle East, southern Europe) and is harvested 180–210 days after seeding [104].

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