Ashwagandha
Research reviewed: up until 05/2023
Ashwagandha (Withania somnifera) is a dietary supplement with 32 published peer-reviewed studies involving 2,057 participants, researched for Anxiety and mood, Arthritis, Muscle Mass and Strength and 10 more areas.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Anxiety and mood
StrongArthritis
ModerateMuscle Mass and Strength
ModerateHypothyroidism
ModerateImmune System
ModerateOxidative Stress
ModeratePerformance Enhancement
StrongPerimenopausal Health
ModerateSexual Function
ModerateSleep
StrongStress
StrongTestosterone and Sperm
StrongTuberculosis
ModerateResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Anxiety and mood
To compare the effects of ashwagandha treatment with a standardised psychotherapy on employees with moderate to severe anxiety
Study Type
Pragmatic randomised controlled trial
Purpose
To compare the effects of ashwagandha treatment with a standardised psychotherapy on employees with moderate to severe anxiety
Dose
600 mg/day of ashwagandha (2 x 300 mg) or placebo
Participants
75 male and female employees with moderate to severe anxiety
Duration
12 weeks
Results
The study found a significant association between naturopathic treatment, which included dietary changes and daily intake of 600 mg of ashwagandha, and a reduction in anxiety symptoms. Additionally, the researchers observed that the naturopathic group experienced better outcomes in terms of fatigue, motivation, concentration, and overall well-being compared to the psychotherapy group. Patient-centred assessments also revealed significant reductions in specific symptoms and improvements in mental health, vitality, social functioning, and general health in the naturopathic group.
How They Measured It
Anxiety levels were assessed using a self-reported questionnaire which measured subjective symptoms of anxiety. Quality of life was also assessed using questionnaires which measured health-related quality of life, physical and mental fatigue, and qualitative patient experiences.
To investigate the stress-relieving and pharmacological activity of ashwagandha extract in stressed adults
Study Type
Randomised, double-blind, placebo-controlled study
Purpose
To investigate the stress-relieving and pharmacological activity of ashwagandha extract in stressed adults
Dose
240 mg/day of standardised ashwagandha extract containing 35% withanolides or placebo
Participants
60 males and females aged 18 to 65 years
Duration
60 days
Results
The study found an association between ashwagandha supplementation and a statistically significant reduction in anxiety symptoms, as measured by Hamilton Anxiety when compared to the placebo. Additionally, a notable but not statistically significant decrease in symptoms of depression, anxiety, and stress, as measured by the Depression, Anxiety, and Stress Scale-21, was observed. Moreover, ashwagandha supplementation was linked to greater reductions in morning cortisol levels, a hormone associated with stress, as well as dehydroepiandrosterone sulphate (DHEAS) levels, a hormone involved in hormone production, compared to the placebo. Reductions of DHEA along with morning cortisol levels may be a marker of decreased stress. The researchers also observed an increase in testosterone levels increased in males but not in females over time, although this change was not statistically significant compared with the placebo.
How They Measured It
Anxiety, depression, and stress were assessed using both clinician-administered and self-reported questionnaires, which measured the severity of anxiety, stress, and depression.
To assess the effects of ashwagandha on improving cognitive performance, mood, anxiety, food cravings, and cortisol levels in healthy adults with high perceived stress
Study Type
Randomised, placebo-controlled between group trial
Purpose
To assess the effects of ashwagandha on improving cognitive performance, mood, anxiety, food cravings, and cortisol levels in healthy adults with high perceived stress
Dose
225 mg/day of ashwagandha root and leaf extract or 400 mg/day of ashwagandha root and leaf extract or placebo
Participants
60 healthy men and women with an average age of 34 years
Duration
30 days
Results
The researchers observed significant improvements over time in self-report assessments for anxiety, stress, depression, perceived stress, and food cravings. However, these improvements were not specific to the intervention group, as the main effect for the group and interactions were not significant. Additionally, significant improvements were observed in cognitive flexibility, visual memory, reaction time, psychomotor speed, and executive functioning, with the Ashwagandha groups often out-performing the placebo group. Cortisol levels in the ashwagandha groups also exhibited reductions, with larger effects observed in the 225 mg/day ashwagandha group. In contrast, the placebo group showed a nonsignificant increase in cortisol levels. In the short term, increased cortisol levels can enhance the body's ability to respond to stressors by providing a burst of energy, heightened focus, and increased alertness.
How They Measured It
Anxiety, depression, and stress were assessed using self-reported questionnaires which measured trait anxiety levels, magnitude of depression, anxiety, and perceived stress. Cognitive ability was assessed using a neurocognitive test which measured verbal memory, visual memory, finger tapping, digit coding, stroop test, attention, and performance.
To evaluate the effects of an aqueous ashwagandha root extract in reducing stress and anxiety in adults
Study Type
Randomised, double-blind, placebo-controlled clinical study
Purpose
To evaluate the effects of an aqueous ashwagandha root extract in reducing stress and anxiety in adults
Dose
250 mg/day of ashwagandha root extract (2 x 125 mg capsules) or 600 mg/day of ashwagandha root extract (2 x 300 mg capsules) or placebo
Participants
60 male and female participants
Duration
8 weeks
Results
The researchers observed that both daily doses of ashwagandha root extract, 250 mg and 600 mg, were both associated with significant improvements in stress and anxiety compared to the placebo. The group taking 600 mg of ashwagandha showed significant reductions in stress and anxiety levels, as well as significant improvement in sleep quality. Meanwhile, the group taking 250 mg of ashwagandha showed a significant reduction in stress levels and serum cortisol. Lower levels of cortisol indicate a decrease in stress response within the body.
How They Measured It
Anxiety was assessed using a clinician-based psychological questionnaire which measures intensity of anxiety. Stress and quality of sleep was assessed using self-reported questionnaires which measure perceived stress, and overall sleep quality.
To evaluate the effects of ashwagandha root extract on patients with generalised anxiety disorder.
Study Type
Randomised, double-blind placebo-controlled study
Purpose
To evaluate the effects of ashwagandha root extract on patients with generalised anxiety disorder.
Dose
1 g/day of ashwagandha or placebo
Participants
40 patients with a confirmed diagnosis of generalised anxiety disorder
Duration
Six weeks
Results
The study found an association between a daily dose of 1g ashwagandha oral intake and greater reduction in anxiety rating scores. The researchers observed a 14-unit reduction in anxiety scores in the ashwagandha group while an 8-unit reduction was observed in the placebo group after six weeks of treatment.
How They Measured It
Anxiety was assessed using a clinician-based questionnaire which measured the severity of generalised anxiety disorder.
To evaluate the effects of ashwagandha extract in patients with anxiety disorders.
Study Type
Randomised, double-blind, placebo-controlled trial
Purpose
To evaluate the effects of ashwagandha extract in patients with anxiety disorders.
Dose
500 mg/day of ashwagandha (2 x 250 mg tablets) or placebo
Participants
39 men and women with an average age of 41
Duration
6 weeks
Results
The study found a trend for superior anti-anxiety effects of Ashwagandha over the placebo at week 2, and statistically significant superior anti-anxiety effects at week 6. Ashwagandha was well tolerated and adverse effects were comparable to those observed after the placebo.
How They Measured It
Anxiety was assessed using the Hamilton Anxiety Scale, a clinician-based questionnaire used to measure the severity of anxiety.
To assess the effects of a standardised extract of ashwagandha in patients with bipolar disorder.
Study Type
Randomised, double-blind, placebo-controlled study
Purpose
To assess the effects of a standardised extract of ashwagandha in patients with bipolar disorder.
Dose
250 mg/day of ashwagandha extract on the first week and 500 mg/day (2 x 250 mg capsules) for the next 7 weeks or placebo
Participants
60 males and females diagnosed with bipolar disorder
Duration
8 weeks
Results
The study revealed a significant association between ashwagandha extract and notable improvements in specific cognitive tasks after an 8-week treatment period. These tasks included remembering numbers in reverse order, responding quickly to neutral stimuli, and accurately identifying emotions. Reported adverse events were mild and temporary (5 participants reported diarrhoea and 3 participants reported sleepiness). No participants withdrew from the study or experienced serious adverse events.
How They Measured It
Cognitive function was assessed using various cognitive assessments that measure executive functions, processing speed, attention/working memory, memory, psychomotor speed, and social cognition.
To investigate the effects of ashwagandha root extract in patients with obsessive-compulsive disorder
Study Type
Randomised, double-blind placebo-controlled trial
Purpose
To investigate the effects of ashwagandha root extract in patients with obsessive-compulsive disorder
Dose
120 mg/day of ashwagandha (4 x 30 mg of ashwagandha extract) or placebo
Participants
30 patients diagnosed with obsessive-compulsive disorder and undergoing treatment with selective serotonin reuptake inhibitors (SSRI) drugs at an adequate dose and duration.
Duration
6 weeks
Results
The study found an association between daily oral supplementation of 120 mg of ashwagandha and significantly greater reduction in obsessive-compulsive disorder symptoms. The researchers observed an 8-unit reduction in obsessive-compulsive disorder symptoms in the treatment group, while the placebo group only had a 2-unit reduction.
How They Measured It
Obsessive-compulsive disorder symptoms were assessed using the Yale-Brown Obsessive Compulsive Scale, a symptom checklist which measures the frequency and severity of the symptoms in OCD patients.
Arthritis
To evaluate the effects of ashwagandha root and leaf extracts in patients with knee joint pain and discomfort.
Study Type
Prospective, randomised, double-blind, placebo-controlled trial
Purpose
To evaluate the effects of ashwagandha root and leaf extracts in patients with knee joint pain and discomfort.
Dose
250 mg/day of ashwagandha (2 x 125 mg capsules) or 500 mg/day of ashwagandha (2 x 250 mg capsules) or placebo
Participants
60 males and females with knee joint pain and discomfort with an average age of 58 years
Duration
12 weeks
Results
The researchers observed that both daily doses of 250 mg and 500 mg of ashwagandha taken over a period of 12 weeks resulted in significant improvements in various measures of osteoarthritis, including the osteoarthritis index score (mWOMAC), knee swelling, pain, stiffness, and disability when compared to baseline and placebo. When comparing the two doses, the 500 mg daily dose of ashwagandha showed better outcomes. Additionally, the 500 mg/day dose showed earlier effects at 4 weeks compared to the 250 mg/day dose.
How They Measured It
Knee joint pain and discomfort were assessed using a self-administered questionnaire which measures pain, stiffness, and physical functional disability in patients with hip and knee osteoarthritis.
Muscle Mass and Strength
To investigate the effects of a standardised ashwagandha (Sensoril) root and leaf extract on strength training adaptations and recovery.
Study Type
Randomised, double-blind, placebo-controlled trial
Purpose
To investigate the effects of a standardised ashwagandha (Sensoril) root and leaf extract on strength training adaptations and recovery.
Dose
500 mg/day of ashwagandha supplementation or placebo taken every morning with 12 fluid ounces of cold tap water
Participants
40 males with an average age of 26 years
Duration
12 weeks
Results
The study found that the daily dose of 500 mg ashwagandha extract, combined with a heavy resistance-training program is associated with the significant improvements in lower-body and upper-body strength after 12 weeks. Additionally, the researchers observed significant improvements in squat power, bench press power, 7.5 km time trial performance, and perceived recovery scores in the ashwagandha group but not in placebo. Furthermore, no change in the android/gynoid ratio was observed in the ashwagandha group, whereas the placebo group experienced a significant increase in android/gynoid ratios. Higher android/gynoid ratios are associated with an increased risk of health conditions such as cardiovascular disease and metabolic disorders.
How They Measured It
Muscular strength was measured through one-repetition bench press and back squat using standard methods
To examine the effects of ashwagandha root extract on muscle mass and strength in healthy young men engaged in resistance training.
Study Type
Randomised, Prospective, Double-Blind, Placebo-Controlled Clinical Trial
Purpose
To examine the effects of ashwagandha root extract on muscle mass and strength in healthy young men engaged in resistance training.
Dose
600 mg/day of ashwagandha (2 x 300 mg capsules with 5% withanolides) or placebo
Participants
57 young males aged 18-50 years with little experience in resistance training
Duration
8 weeks
Results
The researchers observed significant improvements in muscle strength and size in both the ashwagandha group and placebo group, which can be expected with resistance training. However, the ashwagandha group showed significantly greater increases in muscle strength for both the upper and lower body compared to the placebo group. Additionally, the ashwagandha group experienced greater improvements in muscle size, muscle recovery, and a decrease in body fat percentage compared to the placebo group. The study also found an association between ashwagandha treatment and significantly greater increase in serum testosterone.
How They Measured It
Muscular strength was measured through one-repetition leg and bench press using standard methods.
Hypothyroidism
To evaluate the effects of ashwagandha root extract in patients with subclinical hypothyroidism.
Study Type
Randomised, Double-Blind, Placebo-Controlled Clinical Trial
Purpose
To evaluate the effects of ashwagandha root extract in patients with subclinical hypothyroidism.
Dose
600 mg/day of ashwagandha (2 x 300 mg capsules containing 5% withanolides) or placebo
Participants
50 males and females with subclinical hypothyroidism, compared to baseline aged 18-50 years
Duration
8 weeks
Results
Supplementation with ashwagandha root extract for 4 and 8 weeks was associated with a significant increase in serum T3 levels, indicating higher concentrations of this thyroid hormone in the bloodstream. The placebo group, on the other hand, experienced a decrease in serum T3 levels over time. Similarly, ashwagandha treatment was associated with a significant increase in serum T4 concentrations at both the fourth and eighth weeks. T3 and T4 are important hormones for regulating metabolism and energy production in the body. Furthermore, the ashwagandha group exhibited a significant decrease in serum TSH levels compared to the placebo group. A decrease in TSH suggests improved thyroid function and a more balanced production of thyroid hormones. Overall, these findings indicate that ashwagandha supplementation may have positive effects on thyroid hormone levels in individuals with subclinical hypothyroidism.
Immune System
To evaluate the effects of ashwagandha extract in middle to aged healthy population exposed to environmental influences of seasonal change
Study Type
Randomised, double-blind, placebo-controlled trial with an open-label extension
Purpose
To evaluate the effects of ashwagandha extract in middle to aged healthy population exposed to environmental influences of seasonal change
Dose
180 mg/day capsule containing 60 mg of ashwagandha with 21 mg withanolides or placebo
Participants
24 healthy healthy men and women aged 45-72 years
Duration
30 days and an open-label extension study for another 30 days
Results
The study found an association between ashwagandha treatment and significant improvements in the participant’s immune system after 30 days. They had higher levels of certain immune markers, such as antibodies (IgA, IgM, IgG), cytokines (IFN-γ, IL4), and different types of immune cells (TBNK cells). Higher levels of antibodies, cytokines, and immune cells indicate an enhanced immune response. In contrast, the group that received a placebo had a decrease in immune cells and no change in antibody levels or cytokines.
Oxidative Stress
To compare the effect of ashwagandha and guduchi in oxidative stress in healthy volunteers
Study Type
Randomised, double-blind study
Purpose
To compare the effect of ashwagandha and guduchi in oxidative stress in healthy volunteers
Dose
1,000 mg/day of ashwagandha (2 x 500 mg capsules) or 1,000 mg/day guduchi (2 x 500 mg capsules) or placebo
Participants
30 males and females aged 18-45 years
Duration
6 months
Results
The study found that ashwagandha treatment was associated with increased haemoglobin levels. Higher levels of haemoglobin can indicate factors such as improved oxygenation and increased red blood cell production. Additionally, the researchers observed a significant increase in the level of superoxide dismutase and a decrease in the level of malondialdehyde. An increase in superoxide dismutase levels, as observed in the study, suggests that the body's antioxidant defence system is enhanced. It indicates a potential improvement in the body's ability to cope with oxidative stress. In contrast, a decrease in malondialdehyde levels reflects a decrease in the harmful effects of oxidative stress. No adverse effects were found in the trial period of 6 months.
Performance Enhancement
To evaluate the effects of ashwagandha root extract on cardiorespiratory endurance in healthy athletic adults.
Study Type
Randomised Double-Blind, Placebo-Controlled Trial
Purpose
To evaluate the effects of ashwagandha root extract on cardiorespiratory endurance in healthy athletic adults.
Dose
600 mg/day of ashwagandha (2 x 300 mg capsules) or placebo
Participants
50 healthy athletic adults with an average age of 29 years
Duration
8 weeks
Results
The study found an association between ashwagandha supplementation and statistically significant improvements in antioxidant levels and VO₂ max compared to the placebo group. Higher values of VO₂ max indicate better aerobic fitness. In addition, the researchers observed significant improvements in various assessments of recovery, well-being, and performance in the ashwagandha group compared to the placebo group. The TQR (Total Quality Recovery) scores indicated better overall recovery and well-being in the Ashwagandha group. The DALDA (Daily Analysis of Life Demands for Athletes) scores, which measures different aspects of performance, also favoured the ashwagandha group. The RESTQ (Recovery-Stress Questionnaire for Athletes) assessment showed better outcomes in terms of fatigue recovery, lack of energy, and fitness analysis in the ashwagandha group.
How They Measured It
Cardiorespiratory fitness was assessed using Cooper’s 12-minute run test which measured maximum oxygen consumption (VO₂ max).
To investigate the effects of ashwagandha and Terminalia arjuna, both individually and in combination, on physical and cardiovascular performance in healthy young adults.
Study Type
Randomised controlled, parallel group, single-blinded study
Purpose
To investigate the effects of ashwagandha and Terminalia arjuna, both individually and in combination, on physical and cardiovascular performance in healthy young adults.
Dose
500 mg/day of ashwagandha and/or 500 mg/day of Terminalia arjuna or placebo
Participants
40 healthy males and females with an average age of 21 years
Duration
8 weeks
Results
The researchers observed significant improvements in velocity, power, and maximal aerobic capacity (VO₂ max) in participants taking ashwagandha, while those who took Terminalia arjuna had increased VO₂ max and lower resting systolic blood pressure. VO₂ max is a measure of the body's oxygen usage during exercise and higher values indicate better fitness. In addition, a lower resting systolic blood pressure is generally considered beneficial for cardiovascular health. When the two supplements were administered together, improvements were seen in all physical performance and endurance parameters except balance and diastolic blood pressure.
To investigate the effects of ashwagandha supplementation in enhancing the aerobic performance of elite Indian cyclists.
Study Type
Randomised, placebo-controlled trial
Purpose
To investigate the effects of ashwagandha supplementation in enhancing the aerobic performance of elite Indian cyclists.
Dose
1,000 mg/day of Ashwagandha (2 x 500 mg capsules) or a placebo
Participants
40 elite Indian cyclists aged 18-27 years
Duration
8 weeks
Results
The study found a significant association between ashwagandha treatment and improvements in all parameters related to aerobic capacity, such as VO₂ max, metabolic equivalents of tasks (METs), and time to exhaustion on the treadmill.These findings indicate that ashwagandha supplementation can enhance endurance and cardiovascular fitness. VO₂ max measures the body's maximum ability to utilise oxygen during intense exercise, and higher values indicate better aerobic fitness. METs, on the other hand, provide a measure of the intensity of physical activity, and improvements in METs suggest increased aerobic performance and overall fitness levels.
How They Measured It
Aerobic capacity in terms of maximal aerobic capacity (VO₂ max), metabolic equivalent, respiratory exchange ratio (RER), and total time for the athlete to reach his exhaustion stage was determined during a treadmill test in which subjects were asked to perform till volitional exhaustion.
Perimenopausal Health
To evaluate the effects of ashwagandha root extract on climacteric symptoms, quality of life, and hormonal parameters in perimenopausal women.
Study Type
Randomised, double-blind placebo-controlled study
Purpose
To evaluate the effects of ashwagandha root extract on climacteric symptoms, quality of life, and hormonal parameters in perimenopausal women.
Dose
600 mg/day of ashwagandha root extract (2 x 300 mg capsules) or placebo
Participants
100 women with climacteric symptoms
Duration
8 weeks
Results
The study found an association between 600 mg of ashwagandha daily intake and improvement in menopause-specific quality of life. Additionally, the researchers observed a significant increase in serum estradiol. An increase in serum estradiol levels can have several implications, such as supporting reproductive health, promoting bone density, and influencing mood and cognitive function.
How They Measured It
Menopausal symptoms were assessed using self-reported questionnaires: which measured the severity of menopausal symptoms, and its impact on various aspects of a woman's life including vasomotor symptoms (hot flashes), psychosocial symptoms, physical symptoms, and sexual symptoms.
Sexual Function
To evaluate the effects of ashwagandha root extract on sexual performance and well-being in adult males.
Study Type
Randomised, double-blind, placebo-controlled study
Purpose
To evaluate the effects of ashwagandha root extract on sexual performance and well-being in adult males.
Dose
600 mg/day of ashwagandha root extract (2 x 300 mg capsules) or placebo
Participants
50 healthy males aged 21-45 years
Duration
8 weeks
Results
Participants who took the ashwagandha root extract had an 88.5% greater probability of scoring higher on questionnaires about their sexual activity and quality of sexual function Additionally, the ashwagandha group experienced a 17% rise in serum testosterone, while the placebo group only had a 2% change. Participants in the ashwagandha group also showed slight improvement and stability in quality of life parameters compared to the placebo group, although there were no statistically significant improvements observed for either group.
How They Measured It
Sexual activity and quality of sexual function was assessed using a self-reported questionnaire which included questions related to sexual cognition/fantasy, sexual arousal, sexual behaviour/experiences, orgasm, and drive/desire. Quality of life was also assessed using a self-reported questionnaire that evaluated physical functioning, emotional well-being, pain, energy, and fatigue.
To investigate the effects of ashwagandha root extract supplementation on improving sexual function in healthy females.
Study Type
Randomised, Double-Blind, Placebo-Controlled Study
Purpose
To investigate the effects of ashwagandha root extract supplementation on improving sexual function in healthy females.
Dose
600 mg/day of high-concentration ashwagandha root extract (2 x 300 mg capsules) or placebo
Participants
50 women aged 21-50 years
Duration
8 weeks
Results
The study found an association between high-concentration ashwagandha root extract supplementation and a significant increase in female sexual function. Specifically, improvements were observed in lubrication, orgasm, and sexual distress. After 4 and 8 weeks, there was no significant change in the total number of sexual encounters and the number of satisfying sexual experiences for either the ashwagandha or placebo groups. However, after 8 weeks, the ashwagandha group experienced a 126% significant increase in satisfying sexual experiences compared to a 61% increase in the placebo group. The increase in successful sexual encounters implies that participants may have experienced more satisfying sexual experiences, even if the total number of encounters did not rise significantly. This distinction is important as it highlights the potential for improved sexual satisfaction rather than just frequency.
How They Measured It
Female sexual function was assessed using self-reported questionnaires which measure sexual desire, arousal, lubrication, orgasm, satisfaction, pain, distress, and sexual activity.
Sleep
To compare the effects of ashwagandha root extract between healthy subjects and in subjects with insomnia.
Study Type
Randomised, double-blind parallel-group, placebo-controlled study
Purpose
To compare the effects of ashwagandha root extract between healthy subjects and in subjects with insomnia.
Dose
600 mg/day of ashwagandha root extract (2 x 300 mg capsules) or placebo
Participants
80 participants with an average age of 37 years
Duration
8 weeks
Results
The researchers observed significant improvements in all sleep parameters, including sleep onset latency (the time it takes to fall asleep), total sleep time, wake after sleep onset (the duration of wakefulness during the sleep period), time in bed, and sleep efficiency (the percentage of time spent asleep while in bed). The improvements were more notable in individuals with insomnia compared to healthy subjects, suggesting that ashwagandha treatment may have a greater impact on improving sleep in those with existing sleep difficulties. Moreover, improvements in subjective sleep quality were observed for both the ashwagandha group in the healthy study population and the insomnia study group. Additionally, the researchers also noticed a notable reduction in anxiety symptoms among individuals with insomnia who received the ashwagandha supplement.
How They Measured It
Sleep parameters were assessed using actigraphy, a non-invasive method of monitoring human rest and activity cycles such as sleep onset latency, total sleep time, wake after sleep onset, total time in bed, and sleep efficiency. In addition, sleep quality was assessed using a self-reported questionnaire, which measured subjective sleep quality. Anxiety was self-assessed using a psychological questionnaire which measured the severity of perceived anxiety.
To determine the effects of ashwagandha root extract in patients with insomnia and anxiety
Study Type
Randomised, double-blind, placebo-controlled crossover study
Purpose
To determine the effects of ashwagandha root extract in patients with insomnia and anxiety
Dose
600 mg/day of ashwagandha root extract (2 x 300 mg capsules) or placebo
Participants
60 males and females aged 18-60 years.
Duration
10 weeks
Results
The study found an association between ashwagandha treatment and the significantly shorter sleep onset latency after 10 weeks. The researchers also observed significant improvements in other sleep parameters including total sleep time, sleep efficiency and sleep quality. Furthermore, ashwagandha treatment was associated with lower anxiety levels after 10 weeks of treatment with the root extract.
How They Measured It
Sleep onset latency and other sleep parameters was assessed by actigraphy, a non-invasive technique used to get an objective measurement of your sleep schedule. Sleep quality was assessed using a self-reported questionnaire and sleep logs which evaluated mental alertness on rising and quality of sleep. Anxiety was assessed using a self-reported questionnaire which measured mental agitation, psychological distress, and physical complaints related to anxiety.
To investigate the effects of ashwagandha (Sensoril®) in chronically stressed adults
Study Type
Randomised, double-blind, placebo-controlled clinical trial
Purpose
To investigate the effects of ashwagandha (Sensoril®) in chronically stressed adults
Dose
125, 250, and 500 mg/d of ashwagandha capsules or placebo
Participants
97 chronically stressed men and women with an average age of 35 years
Duration
8 weeks
Results
The researcher observed that participants consuming the standardised Withania somnifera extract (Sensoril) experienced positive effects on sleep quality. This improvement is linked to the extract's ability to reduce stress levels, which is known to affect sleep negatively
How They Measured It
Sleep quality and related parameters were assessed using three different measurement tools which collectively measure a comprehensive assessment of sleep quality , sleep disturbances, and overall well-being.
Stress
To evaluate the effects of a high-concentration full-spectrum extract of ashwagandha roots in reducing stress and anxiety and in improving the general well-being on stressed adults.
Study Type
Prospective, randomised double-blind, placebo-controlled study
Purpose
To evaluate the effects of a high-concentration full-spectrum extract of ashwagandha roots in reducing stress and anxiety and in improving the general well-being on stressed adults.
Dose
600 mg/day of ashwagandha (300 mg x 2 capsules) or placebo
Participants
64 men and women with history of chronic stress
Duration
60 days
Results
The study found an association between the daily dose of 600 mg ashwagandha root extract and a significant reduction in scores on all stress-assessment scales on day 60 compared to the placebo group. Additionally, the researchers observed a reduction in serum cortisol levels in the ashwagandha group which is generally considered beneficial and indicative of reduced stress levels.
How They Measured It
Stress was assessed using self-reported questionnaires which measured various dimensions of stress.
To evaluate the effects of ashwagandha root extract on cognitive functions, stress level, sleep, and quality of life in adults with stress.
Study Type
Two-arm, randomised, double-blind, parallel group, placebo-controlled Study
Purpose
To evaluate the effects of ashwagandha root extract on cognitive functions, stress level, sleep, and quality of life in adults with stress.
Dose
300 mg/day of ashwagandha root extract capsules with 15 mg withanolides or placebo
Participants
125 males and females with an average age of 34 years
Duration
90 days
Results
The researchers observed significant improvements in recall memory and a decrease in the total error rate in the ashwagandha treatment group compared to the placebo group. Additionally, the study found associations between ashwagandha treatment and lower stress levels, reduced serum cortisol levels, better psychological well-being, and improved sleep quality. Lower serum cortisol levels suggest reduced stress and improved regulation of the body's stress response.
How They Measured It
Cognitive function was assessed using the Cambridge Neuropsychological Test Automated Battery which included tests of working memory, learning and executive function, visual, verbal, and episodic memory, attention, information processing, reaction time, social and emotion recognition, decision making, and response control. Stress, happiness, and sleep quality were assessed using self-reported questionnaires which measured perceived stress, psychological well-being, and quality and pattern of sleep, respectively.
To evaluate the effects of standardised ashwagandha root extract on overall well-being and stress markers linked to obesity in adults with chronic stress.
Study Type
Randomised, double-blind, placebo-controlled trial
Purpose
To evaluate the effects of standardised ashwagandha root extract on overall well-being and stress markers linked to obesity in adults with chronic stress.
Dose
600 mg/day of standardised ashwagandha root extract (2 x 300 mg capsules with 5% withanolides) or placebo.
Participants
52 men and women aged 16 to 60 years, experiencing chronic stress
Duration
8 weeks
Results
The study found an association between oral ingestion of 600 mg of ashwagandha root extract and significant decrease in perceived stress levels after 4 and 8 weeks of daily consumption. Participants who received the ashwagandha treatment reported feeling happier, experiencing an overall improvement of 19.18%. Additionally, they exhibited improvements in controlling their eating habits and managing emotional eating. Furthermore, the researchers observed reductions in body weight, body mass index, and serum cortisol levels among those who received the ashwagandha treatment. Serum cortisol levels are indicators of stress and can influence appetite. Lower cortisol levels have the potential to improve appetite control and weight management.
How They Measured It
Weight management was assessed using body weight, body mass index, and self-reported questionnaires that evaluated stable dimensions of food cravings and eating behaviour. Stress and general well-being were also assessed using self-reported questionnaires that evaluated perceived stress, happiness, well-being, and optimism.
Testosterone and Sperm
To assess the effects of ashwagandha root extract on sperm production in patients with oligospermia, or low sperm count.
Study Type
Randomised, double-blind, placebo-controlled trial
Purpose
To assess the effects of ashwagandha root extract on sperm production in patients with oligospermia, or low sperm count.
Dose
675 mg/day of ashwagandha root extract (3 x 225 mg capsules) or placebo
Participants
46 infertile male patients aged 22-40 years
Duration
90 days
Results
The study found an association between ashwagandha treatment and significant increases in sperm concentration, semen volume, and sperm motility. Additionally, the researchers observed a 17% increase in serum testosterone and a 34% increase in luteinizing hormone following treatment with ashwagandha root extract compared to the baseline. In males, an increase in luteinizing hormone stimulates the production of testosterone in the testes.
To investigate the effects of ashwagandha on seminal plasma metabolites in infertile men
Study Type
Randomised, double-blind placebo-controlled trial
Purpose
To investigate the effects of ashwagandha on seminal plasma metabolites in infertile men
Dose
5 g/day of ashwagandha root powder or placebo
Participants
180 infertile men in the treatment group and 50 normal healthy fertile men in the control group. Within the treatment group, there were three subgroups of infertile males: 60 men with normal semen parameters but an unknown cause of infertility (normozoospermic), 60 men with low sperm concentration (oligozoospermic), and 60 men with poor sperm motility (asthenozoospermic).
Duration
3 months
Results
The study found that ashwagandha treatment was associated with significant increases in the concentrations of alanine, glutamate, citrate, glycerophosphocholine, and histidine, and a decrease in phenylalanine in the normozoospermic group. Similar findings were observed in the oligozoospermic and asthenozoospermic groups after three months of ashwagandha treatment. These improvements in alanine, glutamate, citrate, GPC, and histidine indicate positive effects on male fertility, as these substances are important biomarkers. Additionally, the decrease in phenylalanine suggests potential improvements in overall health and metabolic profile among men.
To investigate the effects of ashwagandha supplementation in overweight men with mild-to-moderate, self-reported fatigue.
Study Type
Randomised, double-blind, placebo-controlled, crossover study
Purpose
To investigate the effects of ashwagandha supplementation in overweight men with mild-to-moderate, self-reported fatigue.
Dose
600 mg/day of ashwagandha extract (2 x 300 mg capsules with 10.5 mg of of withanolide glycosides) or placebo
Participants
57 overweight males with mild-to-moderate symptoms of fatigue aged 40-70 years
Duration
16 weeks
Results
The researchers observed significant improvements in most symptom scores from baseline to week 8 for both the placebo and ashwagandha conditions. In the placebo group, improvements were observed in psychological, somatic, and sexual symptoms, as well as fatigue-inertia and vigour-activity. Similar improvements were found in the ashwagandha group, except for fatigue-inertia scores which did not show significant improvement. The study also found that daily supplementation of 600 mg ashwagandha was associated with an 18% higher increase in salivary dehydroepiandrosterone sulphate (DHEA-S) and a 14.7% higher increase in testosterone compared to the placebo group. Higher concentrations of DHEA-S are associated with improvements in mood and reductions in fatigue.
How They Measured It
Symptomatic changes and mood states were assessed using self-reported questionnaires which measured psychological, somatic, and sexual symptoms, and fatigue inertia and vigour-activity.
To compare the effects of ashwagandha and pentoxifylline on sperm parameters in idiopathic male infertility.
Study Type
Triple-blind, randomised clinical trial
Purpose
To compare the effects of ashwagandha and pentoxifylline on sperm parameters in idiopathic male infertility.
Dose
5 g/day of ashwagandha extract (6 x 0.83 g capsules) or 800 mg/day of pentoxifylline (6 x 133.33 mg capsules) and placebo
Participants
100 infertile male patients with an average age of 34 years old
Duration
90 days
Results
The researchers observed a significant increase of 12.5% in average sperm count, 21.42% in progressive motility, and 25.56% improvement in sperm morphology with ashwagandha supplementation compared to baseline measurements. Similarly, a significant increase of 16.46% in average semen volume, 25.97% in progressive motility, and 13.28% improvement in sperm morphology compared to baseline was observed with pentoxifylline. However, no statistical differences were found between the treatment groups.
To explore the potential protective effects of ashwagandha in infertile men who were either experiencing psychological stress or were smokers.
Study Type
Randomised trial (uncontrolled)
Purpose
To explore the potential protective effects of ashwagandha in infertile men who were either experiencing psychological stress or were smokers.
Dose
5 g/day of ashwagandha root powder with a cup of skimmed milk
Participants
121 men, aged 25-38 years
Duration
3 months
Results
The study found an association between ashwagandha treatment and improved semen parameters in men. The researchers observed a 17% increase of sperm concentration in men with normal sperm parameters (normozoospermic), 20% in cigarette smokers, and 36% in men experiencing psychological stress. The movement of sperm also improved by 9%, 10%, and 13% in the respective groups along with decrease in their semen liquefaction time by 19, 20 and 34%, as compared with the pretreatment parameters. A decrease in semen liquefaction time improves the chances of successful fertilisation. In addition, the researchers examined the pregnancy outcomes of the men's partners and observed a 15% success rate for men with normal sperm parameters, 15% for men experiencing psychological stress, and 10% for cigarette smokers, leading to an overall success rate of 14%.
Tuberculosis
To examine the impact of ashwagandha when used alongside a short course treatment in individuals newly diagnosed with sputum smear-positive pulmonary tuberculosis.
Study Type
Randomised, double-blind placebo control study
Purpose
To examine the impact of ashwagandha when used alongside a short course treatment in individuals newly diagnosed with sputum smear-positive pulmonary tuberculosis.
Dose
1000 mg/day of ashwagandha root extract (2 x 500 mg capsules) or placebo
Participants
60 newly diagnosed sputum smear-positive patients of pulmonary TB of category 1
Duration
12 weeks
Results
After 8 weeks of treatment, the researchers observed sputum conversion (when the patient's sputum tests negative for the bacteria after a period of treatment) in 86.6% of patients taking ashwagandha as an adjuvant in conjunction with anti-TB drugs, compared to 76.6% in the placebo group. Sputum conversion is a positive response to treatment and indicates a reduction in the bacterial load in the respiratory system. The study also found an association between ashwagandha treatment and the significant increase in CD4 and CD8 counts. An increase in CD4 and CD8 counts refers to an increase in the number of specific types of immune cells called T cells in the blood which may indicate that the immune system is successfully fighting the infection and working to control the disease. In terms of liver function, a smaller percentage of patients in the ashwagandha group had increased levels of SGOT (serum glutamic oxaloacetic transaminase) and SGPT (serum glutamic pyruvic transaminase), which are enzymes that indicate liver health, compared to the placebo group. This is a positive result, as it shows that the treatment may be gentler on the liver. Furthermore, elevated levels of serum uric acid (>6 mg/dl) were observed in 20% of patients in the study group and 33.33% in the placebo group. Elevated uric acid levels can sometimes indicate certain health issues. Lastly, patients in the ashwagandha group reported a better overall improvement in their quality of life compared to the placebo group.
Frequently Asked Questions
Common questions about Ashwagandha research
There are currently 32 peer-reviewed studies on Ashwagandha (Withania somnifera), involving 2,057 total participants. Research covers Anxiety and mood, Arthritis, Muscle Mass and Strength and 10 more areas. The overall evidence strength is rated as Very Strong.
The evidence is currently rated as "Very Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (32 human studies), and reported outcomes.
Ashwagandha has been researched for: Anxiety and mood, Arthritis, Muscle Mass and Strength, Hypothyroidism, Immune System, Oxidative Stress, Performance Enhancement, Perimenopausal Health, Sexual Function, Sleep, Stress, Testosterone and Sperm, Tuberculosis. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 32 out of 32 studies are human trials. Human trials carry more weight in our evidence scoring system.
Similar Supplements
Other supplements researched for similar health goals
