Benefits
Testosterone and Muscle
Increases muscle strength and endurance. A 2015 study showed 600 mg daily for 8 weeks enhanced muscle mass and reduced exercise-induced damage in men.
Stress and Anxiety Relief
Lowers cortisol levels, reducing stress and anxiety. A 2022 study showed 300 mg daily for 8 weeks reduced anxiety scores by ~30% in adults
Improved Sleep
Enhances sleep quality and duration. A 2020 study found 600 mg daily for 8 weeks improved sleep in insomniacs, with faster sleep onset.
Male Fertility and Testosterone
Improves testosterone and sperm quality. A study found 600 mg daily for 8 weeks raised testosterone by ~15% in men.
Cognitive Function
Boosts memory, focus, and reaction time. A 90-day study with 300 mg twice daily improved cognitive function in adults with mild impairment.
Blood Sugar Control
May lower fasting blood glucose. A 2020 study showed 250 mg daily for 8 weeks improved glucose levels in type 2 diabetics.
Mechanism of action
Adaptogenic Activity
Ashwagandha modulates the hypothalamic-pituitary-adrenal (HPA) axis, reducing cortisol levels and mitigating stress responses. It helps regulate the body's reaction to stressors by balancing stress hormones.
GABA-Mimetic Effects
Withanolides may enhance gamma-aminobutyric acid (GABA) receptor activity in the brain, promoting calming effects, reducing anxiety, and improving sleep. This contributes to its sedative properties.
Cognition Mechanism
It promotes neurogenesis and protects neurons by reducing excitotoxicity and enhancing brain-derived neurotrophic factor (BDNF) levels, potentially improving cognitive function and mood.
Hormonal Modulation
Ashwagandha may influence thyroid function by increasing T3 and T4 levels, supporting metabolism in those with subclinical hypothyroidism. It also boosts testosterone in men by reducing cortisol-induced suppression and enhancing luteinizing hormone activity.
Immunomodulation
It balances immune responses by modulating T-cell activity and cytokine production, which may benefit autoimmune conditions or immune suppression, though this requires caution in certain diseases.
Clinical trials
Prospective, randomized, double-blind, placebo-controlled trial evaluating safety and efficacy of high-concentration full-spectrum ashwagandha root extract (KSM-66®, 300 mg twice daily) in 64 chronically stressed adults for 60 days. Outcomes: Perceived Stress Scale, General Health Questionnaire, Depression Anxiety Stress Scale, serum cortisol. (Chandrasekhar, Kapoor, Indian J Psychol Med)
64 chronically stressed adults. 60-day intervention.
Ashwagandha significantly reduced PSS scores (-44% vs -5.5% placebo), GHQ-28 scores, and serum cortisol (-27.9% vs -7.9% placebo) compared to placebo. Established the foundational evidence for KSM-66® as an adaptogen. Generally well-tolerated; the most-cited modern ashwagandha clinical trial.
Randomized, double-blind, placebo-controlled trial of sustained-release ashwagandha root extract (Prolanza™, 300 mg/day) vs placebo in healthy adults for 90 days. Cognitive battery and stress measures assessed.
Healthy adults with self-reported stress. 90-day intervention.
Sustained-release ashwagandha improved cognitive performance, stress scores (PSS), and quality of life vs placebo. Authors propose sustained-release formulation provides 24-hour stable plasma levels.
16-week, randomized, double-blind, placebo-controlled, crossover trial (ACTRN12617000971336) investigating Shoden® ashwagandha extract (21 mg providing 35% withanolide glycosides) in 57 overweight men aged 40-70 with mild fatigue. Outcomes: DHEA-S, testosterone, cortisol, fatigue scores. (Lopresti, Drummond, Inarejos-García, Am J Mens Health)
57 overweight men aged 40-70 with mild fatigue. 16-week crossover.
Shoden® ashwagandha increased DHEA-S by 18% and testosterone by 14.7% vs placebo (p<0.05). Reduced fatigue, improved sexual and psychological wellbeing scores. Safe and well-tolerated. Supports ashwagandha's effects on the HPA axis and androgens in aging men.
Randomized, double-blind, placebo-controlled trial of ashwagandha root extract (600 mg/day) in 144 healthy adults over 60 days. Sleep parameters: PSQI scores, sleep efficiency, sleep onset latency. (Sleep Medicine)
144 healthy adults with self-reported sleep difficulty. 60-day intervention.
Ashwagandha significantly improved sleep efficiency (+72% in extract group), PSQI scores, sleep onset latency, total sleep time, and Hamilton anxiety scale vs placebo. Effects appeared by week 4 and progressed through week 8. No safety concerns. Supports ashwagandha for non-clinical insomnia.
60-day, randomized, double-blind, placebo-controlled trial investigating Shoden® ashwagandha extract (240 mg once daily) in 60 adults with mild-to-moderate anxiety. Outcomes: HAM-A scores, DASS-21, serum cortisol, DHEA-S, testosterone. (Medicine)
60 mildly anxious adults. 60-day intervention.
Shoden® significantly reduced HAM-A scores vs placebo (group difference: 1.55 points, p=0.05). Reductions in morning cortisol (-23% vs -10% placebo). DHEA-S increased significantly. Testosterone showed favorable trend in men. Supports anxiolytic and HPA-modulating effects.
Randomized, double-blind, placebo-controlled trial of KSM-66® ashwagandha root extract (600 mg/day) in 50 healthy athletic adults over 8 weeks. Outcomes: VO2 max via Cooper test, total quality recovery scale. (Choudhary, Shashi, Ayu)
50 healthy athletic adults. 8-week intervention.
KSM-66® significantly improved VO2 max (+13% vs +6% placebo) and quality of recovery scores vs placebo. Demonstrates ergogenic potential in trained subjects. One of several ashwagandha athletic-performance studies, with consistent direction of effect across small clinical trials.
Randomized, double-blind, placebo-controlled trial in 80 healthy volunteers (40 male, 40 female) evaluating ashwagandha root extract (300 mg twice daily) over 8 weeks. Comprehensive safety panel: hematology, biochemistry, liver/kidney function, ECG, vital signs.
80 healthy volunteers (gender-balanced). 8-week safety study.
No clinically significant changes in any safety parameter. Liver and kidney function remained within normal range throughout. Hematology and ECG unchanged. Adverse events comparable to placebo. Confirms acceptable short-term safety profile of standardized ashwagandha root extracts. Note: rare reports of ashwagandha-associated liver injury have been documented in pharmacovigilance literature, warranting caution despite clinical trial safety data.