Formulation:

Various parts of the ashwagandha plant are used, but the most common supplemental form is an extract of its roots that may come in a capsule, liquid extraction, tablets, or tea. When ashwagandha is used as part of the Ayurvedic system, it usually involves more than just the herb alone.

Because withanolides are considered to be the major active component in ashwagandha, some extracts are standardized to contain a certain or minimum amount. Clinical trials have used standardized extracts containing anywhere from 1.5% to 35% withanolides, but many studies do not disclose this information, and the optimal amount of withanolides is not yet clear.^{[1][2][3][4][5][6][7]} Note that while studies may use standardized extracts or proprietary formulas, variations in extraction methods, formulation, or composition can affect the physiological response.

Range of dosages studied:

Studies on ashwagandha have used daily dosages ranging from 120 to 12,000 mg of a root extract. The most common dosing protocol is 150 to 600 mg daily, and this may be divided into one to three doses.^[8][9][5]

Effective Dosages:

Stress

Adults: In studies in adults (ages 18–65+), ashwagandha given in dosages from 120 to 600 mg per day, for 4 to 12 weeks’ duration, has shown effectiveness for the relief of stress and reduction of cortisol. In these studies, both capsules and root powder were taken once or twice daily with water.^{[10][11][10][9][12][13][14][15]}

Sleep

Adults: In studies in adults (ages 18–65+) both with and without insomnia, ashwagandha given in dosages from 120 to 1,250 mg per day (most commonly 600 mg per day) for 4 to 12 weeks’ duration has shown effectiveness for improving alertness/fatigue, sleep quality, sleep duration, and sleep disturbances.^[5] Standardized capsules of root extract were used in the overwhelming majority of studies, taken once or twice daily in combination with milk or water.^{[8][16][10][17][18][19][5]}

Special considerations: The trials used different standardized extracts, some coming from root only and others from both root and leaves. This may result in different phytochemical profiles.

Hormonal health

Men: Men (ages 18–64) who took ashwagandha in dosages from 600 to 5,000 mg per day for 8–12 weeks’ duration saw increases in sexual function, fertility, and testosterone levels. Root extract capsules or powder were taken once or twice daily.^{[7][20][21][22][23][24][25][26][27][14][5]}

Women: Women (ages 18–64) who took 300 mg of ashwagandha root extract twice a day saw increases in estrogen and sexual function as well as decreases in follicle-stimulating hormone, luteinizing hormone, and menopausal symptoms.^[28][29]

Mood and Brain Health

Adults: In studies in adults (ages 18–65+) both with and without anxiety/depression, ashwagandha given in dosages from 120 to 1,000 mg per day (with one outlier giving 12,000 mg per day) for 4 to 12 weeks’ duration was effective for reducing symptoms of anxiety and improving cognition. Capsules of root extract were taken once or twice daily in combination with milk or water.^{[9][5][30][10][12][8][31][13][1][32][33][34][35][36][37][38][39][40][41]}

Special considerations: Just one trial used 12,000 mg per day, which is 20 times the dose most commonly seen in trials (600 mg per day).^[9]

Immune Function

Adults: In studies in adults (ages 18–65+) without known health conditions, ashwagandha given in dosages ranging from 60 to 1,000 mg per day (once or twice daily) for 4 to 16 weeks’ duration has been effective in altering markers of immune function. Capsules, root powder, and tablets were used in these studies that saw increased lymphocytes (CD3, CD4, and CD8), immunoglobulin A,immunoglobulin G, immunoglobulin M, interleukin 4, and natural killer cells and decreased signs of oxidation and inflammation.^{[42][11][4][43][20][44]}

Exercise and Fitness

Adults: In studies in both trained and untrained adults (ages 18–64), ashwagandha given in dosages from 120 to 1,250 mg per day for 2 to 8 weeks’ duration has shown effectiveness for improving aerobic exercise metrics, exercise recovery, and physical strength. In these studies, capsules were taken once or twice per day.^{[6][45][46][47][48][11][5][26]}

Other Considerations:

It is unknown if ashwagandha loses its potency with daily long-term use, but due to its possible drug-like effects on neurotransmission, this possibility cannot be ruled out. It’s also unknown if taking breaks from ashwagandha or taking it every other day prolongs its effectiveness. Whether ashwagandha is taken with milk or water could potentially affect its absorption. More research is needed to confirm whether dosages above 600 mg daily yield greater benefits.