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
Stress and Anxiety Reduction (2012)
Study: A prospective, randomized, double-blind, placebo-controlled trial evaluated the safety and efficacy of a high-concentration full-spectrum ashwagandha root extract (KSM-66, 5% withanolides, 300 mg twice daily) in 64 adults with chronic stress over 60 days.
Findings: Ashwagandha significantly reduced Perceived Stress Scale (PSS) scores by 44% (vs. 5.5% for placebo, p < 0.0001), serum cortisol levels by 27.9% (vs. 7.9% for placebo, p = 0.0006), and improved scores on the Depression Anxiety Stress Scale (DASS) and General Health Questionnaire (GHQ-28). No serious adverse events were reported, indicating safety and tolerability.
Link: Indian J Psychol Med
Cognitive Function and Stress in Healthy Adults (2021)
Study: A randomized, double-blind, placebo-controlled trial (CTRI/2019/11/021990) assessed a sustained-release ashwagandha root extract (Prolanza™, 300 mg once daily) in 130 healthy adults (20–55 years) with moderate stress (PSS 14–24) over 90 days.
Findings: Ashwagandha improved memory and focus (measured by Cambridge Neuropsychological Test Automated Battery, CANTAB), reduced PSS-10 scores (13.0 vs. 18.7 for placebo, p < 0.0001), lowered serum cortisol (p = 0.0443), and enhanced sleep quality (Pittsburgh Sleep Quality Index, p < 0.0001) and psychological well-being (Oxford Happiness Questionnaire, p < 0.0001). No adverse events were reported.
Link: J Diet Suppl
Stress and Hormonal Effects in Aging Males (2019)
Study: A 16-week, randomized, double-blind, placebo-controlled, crossover trial (ACTRN12617000971336) investigated ashwagandha extract (Shoden, 21 mg withanolide glycosides daily) in 57 overweight men (40–70 years) with mild fatigue.
Findings: Improvements in fatigue, vigor, and sexual/psychological well-being were observed, but differences were not statistically significant compared to placebo. Salivary cortisol, DHEA-S, testosterone, and estradiol levels showed no significant between-group differences, though testosterone increased in males over time (p = 0.038). The trial noted good tolerability with no serious adverse events.
Link: Am J Mens Health
Sleep Quality in Healthy Adults (2020)
Study: A randomized, double-blind, placebo-controlled trial evaluated ashwagandha root extract (600 mg/day) in 144 healthy adults over 60 days for sleep quality.
Findings: Ashwagandha significantly improved sleep quality (Pittsburgh Sleep Quality Index) and reduced sleep onset latency compared to placebo (p < 0.05). No adverse events were reported, supporting safety for sleep-related use.
Link: Sleep Med
Stress and Anxiety in Healthy Adults (2019)
Study: A 60-day, randomized, double-blind, placebo-controlled trial (CTRI/2017/08/009449) investigated ashwagandha extract (Shoden, 240 mg once daily) in 60 stressed healthy adults.
Findings: Ashwagandha reduced Hamilton Anxiety Rating Scale (HAM-A) scores (p = 0.040) and showed a near-significant reduction in DASS-21 scores (p = 0.096). It lowered morning cortisol (p < 0.001) and DHEA-S (p = 0.004) and increased testosterone in males (p = 0.038, not significant vs. placebo). No adverse events were reported.
Link: Medicine (Baltimore)
Cardiorespiratory Endurance in Athletic Adults (2015)
Study: A randomized, double-blind, placebo-controlled trial assessed ashwagandha root extract (KSM-66, 600 mg/day) in 50 healthy athletic adults over 8 weeks.
Findings: Ashwagandha significantly improved maximal oxygen capacity (VO2 max, p < 0.05) and quality of life compared to placebo, with no reported adverse events, suggesting efficacy in enhancing physical performance.
Link: Ayu
Safety in Healthy Volunteers (2021)
Study: A randomized, double-blind, placebo-controlled trial in 80 healthy volunteers (40 males, 40 females) evaluated ashwagandha root extract (300 mg twice daily) over 8 weeks.
Findings: No significant changes in hematological, biochemical, thyroid, or vital parameters were observed compared to placebo. Clinical adverse events were minimal and comparable to placebo, confirming safety.
Link: ScienceDirect
Potential Side Effects
Gastrointestinal issues
Nausea, vomiting, diarrhea, or stomach upset.
Drowsiness
Can cause sedation, especially when combined with other calming medications.
Headache
Some users report mild to moderate headaches.
Allergic reactions: Rare, but may include rash, itching, or swelling.
Low Blood Pressure
May lower blood pressure, which can be an issue for those on related medications.
Liver Issues
Rare cases of liver injury have been reported, particularly with high doses or poor-quality supplements.
Hormonal Issues
May affect thyroid hormones or testosterone levels, potentially problematic for those with thyroid conditions or hormone-sensitive disorders.