Ashwagandha, also known by its botanical name Withania somnifera, is a small woody plant with yellow flowers native to India and North Africa.
It’s classified as an adaptogen, as it’s believed to help your body manage stress better.
The plant — mainly its root — has been used for over 3,000 years as a natural Ayurvedic remedy against various ailments.
Modern science also links it to health benefits, such as reduced stress and anxiety and improved blood sugar levels, mood, and memory.
This article reviews the optimal dosages needed to reap different health benefits.
Ashwagandha can reduce stress and anxiety
Ashwagandha is best known for its stress-lowering effects.
The medicinal herb appears to help lower cortisol levels, a hormone your adrenal glands produce in response to stress. More specifically, 125 mg to 5 grams daily for 1–3 months has been shown to lower cortisol levels by 11–32%.
Moreover, 500–600 mg of ashwagandha per day for 6–12 weeks may reduce anxiety and lower the likelihood of insomnia in people with stress and anxiety disorders.
Summary: Ashwagandha seems effective at lowering symptoms of stress and anxiety. Most benefits are linked to 500–600 mg daily taken for at least one month.
Ashwagandha may lower blood sugar levels
Ashwagandha may also lower blood sugar levels in healthy individuals and people with diabetes.
In a tiny, 4-week study of 25 people, ashwagandha reduced fasting blood sugar levels three times more than a placebo.
In another study in people with type 2 diabetes, an ashwagandha supplement taken for 30 days helped lower fasting blood sugar levels as effectively as oral diabetes medication.
Dosages in these studies varied between 250 mg to 3 grams and were generally split into 2–3 equal doses spread evenly over the day.
Summary: Ashwagandha may help lower blood sugar levels. Benefits appear to start at dosages as little as 250 mg per day.
Ashwagandha can boost fertility
Ashwagandha may help boost fertility and promote reproductive health, especially in men.
In one 3-month study of 75 men experiencing infertility, five grams of ashwagandha daily increased sperm count and motility.
In another study on highly stressed men, five grams of ashwagandha per day also improved sperm quality. Moreover, by the end of the 3-month study, 14% of their partners had become pregnant.
Other studies report similar results with comparable dosages.
Summary: Five grams of ashwagandha per day may boost fertility in men in as little as three months.
Ashwagandha may enhance muscle growth and strength
Supplementing with ashwagandha may also increase muscle mass and strength.
In one 8-week study, men given 500 mg of this medicinal herb per day increased their muscular power by 1%, whereas the placebo group experienced no improvements.
In another study in men, 600 mg of ashwagandha per day for eight weeks led to a 1.5–1.7 times larger increase in muscle strength and a 1.6–2.3 times higher increase in muscle size compared to a placebo.
Similar effects were observed with 750–1,250 mg of ashwagandha per day taken for 30 days.
Summary: Daily doses of 500 mg of ashwagandha may increase muscle mass and strength in as little as eight weeks. While most studies have focussed on men, some research suggests women may reap the same benefits.
Ashwagandha might lower inflammation and help fight infection
Ashwagandha may also help lower inflammation and boost your immunity.
Research shows that 12 ml of ashwagandha root extract per day may increase levels of immune cells, which help fight infection.
Suggested read: 12 powerful ayurvedic herbs and spices with health benefits
Moreover, a daily intake of 250–500 mg of ashwagandha over 60 days may reduce C-reactive protein levels by up to 30%, a marker of inflammation.
Summary: Ashwagandha may lower inflammation and help fight infection. Supplements containing at least 250 mg of ashwagandha or 12 ml of ashwagandha extract appear to offer the most benefits.
Ashwagandha can boost memory
Ashwagandha is traditionally used in Ayurveda to help boost memory, and some scientific studies support this practice.
For instance, in a small, 8-week study, 300 mg of ashwagandha root extract twice a day improved general memory, attention, and task performance significantly more than a placebo.
Moreover, healthy men given 500 mg of the medicinal herb daily for two weeks performed significantly better on tests for task performance and reaction time than those given a placebo.
Human research in this area is limited, and more is needed before solid conclusions can be drawn.
Summary: Consuming 500–600 mg of ashwagandha root extract per day may boost various aspects of memory. However, more studies are needed to confirm these effects.
Safety and side effects of ashwagandha
Ashwagandha is considered safe for most people.
However, pregnant or breastfeeding women and people with autoimmune diseases, such as lupus, rheumatoid arthritis, type 1 diabetes, and Hashimoto’s thyroiditis, may need to avoid it.
Ashwagandha may also interact with thyroid, blood sugar, and blood pressure medications.
People taking these types of medication should consult their doctor before supplementing with the medicinal herb.
Keep in mind that most of the studies on ashwagandha were small and of low quality. For this reason, the information on the effectiveness and safety of dosages may be inaccurate. More research is needed.
Suggested read: The 7 best vitamins and supplements for stress
Summary: Ashwagandha is considered safe for most people. However, pregnant or breastfeeding women, people with autoimmune disorders, and those taking certain medications may need to avoid it.
Ashwagandha is a medicinal herb that may offer several health benefits, such as improved blood sugar, inflammation, mood, memory, stress, and anxiety, as well as a boost in muscle strength and fertility.
Dosages vary depending on your needs, but 250–500 mg daily for at least one month seems adequate.