Ashwagandha (Withania somnifera) is an Ayurvedic herb that has been used traditionally for thousands of years. Today, it is widely used as a dietary supplement for stress, sleep, physical performance, male fertility, and testosterone support.

But how much ashwagandha should you actually take? Does ashwagandha increase testosterone? Can it affect blood sugar? And is it safe to take every day?

The answer depends on the form of ashwagandha, the dose, the duration of use, and the reason you are taking it. Research has found potential benefits across several areas, but the evidence is not equally strong for every claimed benefit.

Key Takeaways

• Ashwagandha is an adaptogenic herb traditionally used in Ayurveda and is also known as Withania somnifera.
• Research suggests that certain ashwagandha preparations may help reduce stress and improve sleep.
• Some clinical studies have found increases in testosterone in men, although researchers have not established a single optimal testosterone-specific dose.
• Studies examining testosterone have commonly used 300 mg of standardized root extract twice daily, although some studies have used substantially higher amounts.
• Short-term use appears reasonably well tolerated in many people, but long-term safety has not been established.
• Ashwagandha may interact with medications and may not be appropriate for people with certain medical conditions.

What Is Ashwagandha?

Ashwagandha is a small shrub native to India and parts of Africa and the Middle East. Its botanical name is Withania somnifera. The plant contains several bioactive compounds, including withanolides, which are thought to contribute to some of its biological effects.

Ashwagandha is traditionally used in Ayurveda as a Rasayana, a category of preparations associated with supporting vitality and overall wellbeing.

Modern supplements may contain:

• Ashwagandha root powder
• Ashwagandha root extract
• Root-and-leaf extracts
• Standardized extracts containing specified concentrations of withanolides

This distinction matters because a milligram of ashwagandha powder is not necessarily equivalent to a milligram of a concentrated extract. Clinical research has used a variety of preparations, making it difficult to establish one universal dose.

What Are the Potential Benefits of Ashwagandha?

Research has investigated ashwagandha for several different outcomes. The strength of evidence varies by use.

1. Stress and Cortisol

Stress is one of the most researched uses of ashwagandha.

Clinical studies have reported reductions in perceived stress and cortisol among people taking certain ashwagandha extracts. For example, one randomized, double-blind, placebo-controlled clinical trial found that participants taking 250 or 600 mg of an ashwagandha extract daily for eight weeks experienced reductions in perceived stress and cortisol compared with placebo.

A 2025 systematic review and meta-analysis of randomized controlled trials also found that ashwagandha supplementation was associated with lower cortisol levels, although the studies used different preparations and doses.

Bottom line: Ashwagandha may help with stress, but the optimal preparation and dose have not been firmly established.

2. Sleep

Ashwagandha has also been studied for sleep quality.

A systematic review and meta-analysis of five randomized controlled trials involving 400 participants found a small but significant improvement in overall sleep with ashwagandha extract. The effects were more prominent among adults with insomnia and in studies using doses of at least 600 mg/day for at least eight weeks.

Bottom line: There is some evidence that ashwagandha may support sleep, but it should not automatically be considered a treatment for a sleep disorder.

3. Exercise Performance and Recovery

Several clinical trials have examined ashwagandha in people participating in resistance training or athletic activity.

One randomized controlled trial involving 57 men gave participants 300 mg of ashwagandha root extract twice daily for eight weeks alongside resistance training and evaluated muscle strength, muscle size, recovery, and testosterone.

Bottom line: Ashwagandha may support certain measures of physical performance, but it should not replace the fundamentals of training, nutrition, recovery, and sleep.

Does Ashwagandha Increase Testosterone?

Some research suggests that ashwagandha may increase testosterone levels in men, but the evidence is still developing and there is no established optimal dose specifically for raising testosterone.

Several clinical trials have reported increases in testosterone following ashwagandha supplementation.

For example, an eight-week randomized controlled trial involving men undergoing resistance training used 300 mg of ashwagandha root extract twice daily. The study assessed testosterone alongside muscle strength, muscle size, and recovery.

Another randomized, double-blind, placebo-controlled study involving 50 adult men with lower sexual desire also used 300 mg twice daily for eight weeks and evaluated sexual function and serum testosterone.

Research in aging, overweight men has also reported an increase in testosterone following supplementation with a standardized ashwagandha extract. In that study, the ashwagandha group experienced a 14.7% greater increase in testosterone compared with placebo.

Most recently, a 2026 systematic review and meta-analysis of 23 randomized controlled trials involving 1,706 participants found that ashwagandha supplementation increased testosterone in men. However, the researchers noted heterogeneity and limited data for some endpoints and called for further standardized trials.

How might ashwagandha affect testosterone?

The exact mechanism is not fully understood.

One possibility is that its effects on the body's stress response may indirectly influence reproductive hormones. Ashwagandha has been studied for its effects on cortisol and other components of the hypothalamic-pituitary-adrenal axis, while testosterone production is regulated through the hypothalamic-pituitary-gonadal axis.

However, it would be inaccurate to describe ashwagandha simply as a "testosterone booster." The available evidence is more nuanced.

Can Ashwagandha Lower Blood Sugar?

Possibly, but the evidence remains uncertain.

A 2026 systematic review and dose-response meta-analysis examined 11 randomized controlled trials involving 667 participants. Ashwagandha was associated with a modest reduction in fasting blood glucose compared with placebo, while the effect on HbA1c was inconclusive. The researchers rated the certainty of evidence as very low and concluded that the findings were not sufficient to make clinical recommendations.

An earlier systematic review covering 24 studies - including 5 clinical studies also reported changes in blood glucose, HbA1c, insulin, lipid profiles, and oxidative stress markers, while emphasizing that the available clinical evidence was insufficient for robust conclusions.

Laboratory research has also investigated compounds such as withaferin A for their potential effects on glucose metabolism.

However, larger, well-designed clinical trials are needed before ashwagandha can be considered an established treatment for diabetes or high blood sugar.

This is particularly important because combining ashwagandha with blood-sugar-lowering medication could potentially affect glucose levels.

Ashwagandha should not be used as a replacement for prescribed diabetes treatment.

How Long Does Ashwagandha Take to Work?

There is no single answer because the effects depend on what you are taking it for.

Clinical studies have commonly evaluated outcomes after 6–12 weeks of supplementation.

For example:

• Stress studies have examined outcomes after approximately 8 weeks.
• Several testosterone studies have evaluated participants after 8 weeks.
• Some male fertility studies have used supplementation for approximately 3 months.
• Sleep studies have evaluated outcomes over several weeks.

Therefore, taking ashwagandha once or twice and expecting an immediate effect does not reflect how it has generally been studied.

Is It Safe to Take Ashwagandha Every Day?

Ashwagandha appears to be reasonably well tolerated by many people when used for short periods, but long-term safety remains uncertain.

The National Center for Complementary and Integrative Health (NCCIH) states that ashwagandha may be safe when used in the short term, for up to approximately three months, while there is insufficient information to determine its long-term safety.

Possible side effects include:

• Stomach discomfort
• Diarrhea
• Vomiting
• Drowsiness

There have also been rare reports of liver injury associated with ashwagandha supplements, according to the NCCIH.

Who should avoid or discuss ashwagandha with a healthcare professional?

Extra caution is warranted if you:

• Are pregnant or breastfeeding
• Have a thyroid disorder
• Have an autoimmune condition
• Have liver problems
• Have hormone-sensitive prostate cancer
• Are preparing for surgery
• Take medications for diabetes
• Take medications for high blood pressure
• Take thyroid medication
• Take immunosuppressants
• Take sedatives or certain anti-seizure medications

The NCCIH notes that ashwagandha may interact with several types of medication, including medicines for diabetes and high blood pressure, immunosuppressants, sedatives, anticonvulsants, and thyroid hormone medications.

Ashwagandha Root vs. Extract: Does It Matter?

Yes.

One of the biggest problems when comparing ashwagandha studies is that not all ashwagandha products are the same.

A study might use:

• Whole root powder
• Root extract
• Root-and-leaf extract
• A standardized extract
• A specific concentration of withanolides

Therefore, saying "600 mg of ashwagandha was used in a study" without identifying the preparation can be misleading.

For example, 600 mg of a concentrated standardized extract is not necessarily equivalent to 600 mg of raw root powder.

When evaluating an ashwagandha supplement, look beyond the headline milligram number and check:

1. Plant part: root, leaf, or root + leaf
2. Form: powder or extract
3. Standardization: whether the product specifies withanolide content
4. Serving size: how much is actually consumed per day
5. Quality testing: whether the manufacturer provides appropriate testing and quality information

Looking for an Ashwagandha-Based Supplement for Male Performance?

If your goal is to incorporate ashwagandha into a broader daily routine for male performance, you may prefer a formulation that combines ashwagandha with other traditionally used ingredients rather than taking a single-ingredient supplement.

VitaSteron by Mars is one such formulation. It combines ashwagandha with other ingredients used in formulations for male vitality and performance.

The important distinction is that the clinical research discussed in this article applies to specific ashwagandha preparations and doses. You should not assume that the results of a study using a particular standardized extract automatically apply to every supplement containing ashwagandha.

If you're considering VitaSteron specifically, review the ingredient amounts and formulation on the product label and choose a product based on your individual needs and health circumstances.

Explore VitaSteron by Mars →

Frequently Asked Questions About Ashwagandha

What is ashwagandha?

Ashwagandha (Withania somnifera) is a medicinal herb traditionally used in Ayurveda. Modern research has investigated its potential effects on stress, sleep, physical performance, testosterone, fertility, and other health outcomes.

Does ashwagandha increase testosterone?

Some randomized controlled trials and a 2026 meta-analysis of 23 RCTs suggest that ashwagandha can increase testosterone levels in men. However, the effect varies between studies, and more standardized research is needed.

What is the best dose of ashwagandha for testosterone?

There is no universally established optimal dose. Several clinical studies investigating testosterone have used 300 mg of standardized root extract twice daily, or 600 mg/day. Other studies have used different preparations and doses.

Does ashwagandha lower blood sugar?

A 2026 meta-analysis of 11 randomized controlled trials found a modest reduction in fasting blood glucose, but the evidence was rated very low certainty and the effect on HbA1c was inconclusive.

How long does ashwagandha take to increase testosterone?

Clinical studies examining testosterone have commonly evaluated supplementation over approximately 8 weeks, while some fertility studies have lasted around three months. This does not establish a guaranteed timeline for an individual.

Is ashwagandha safe?

According to the NCCIH, ashwagandha appears to be reasonably well tolerated for many people in the short term. However, long-term safety is not well established, and it can cause side effects or interact with medications.

Can women take ashwagandha?

Women have also participated in clinical studies of ashwagandha. However, the appropriate use and dose depend on the intended purpose and individual circumstances. The NCCIH advises against ashwagandha during pregnancy and breastfeeding.

The Bottom Line

Ashwagandha is one of the more extensively studied Ayurvedic herbs, but its benefits should not be overstated.

Research suggests that certain ashwagandha preparations may help with stress, sleep, and some measures of physical performance. There is also growing evidence that supplementation may increase testosterone in men, particularly in studies using standardized extracts over several weeks.

Ashwagandha may also influence blood sugar, which makes it particularly important to consider potential interactions with diabetes medications.

Ultimately, the form of ashwagandha matters as much as the number of milligrams on the label. Choosing a well-characterized product and considering your individual health circumstances is more useful than simply choosing the highest dose.

For those looking for a multi-ingredient supplement rather than standalone ashwagandha, VitaSteron by Mars combines ashwagandha with other ingredients in a formulation designed around male vitality and performance.

This article is for informational purposes only and is not a substitute for medical advice. If you have a medical condition, take prescription medication, or are considering ashwagandha for a specific health concern, speak with a qualified healthcare professional before using it.