Ashwagandha: Benefits, Uses, and What Research Says

In this article

1. What is ashwagandha and where does it come from?
2. What does ashwagandha contain?
3. What benefits of ashwagandha have been studied?
4. Can ashwagandha help with stress and anxiety?
5. Can ashwagandha improve sleep?
6. Can ashwagandha support physical performance?
7. What other effects of ashwagandha are being studied?
8. How long does ashwagandha take to work?
9. How much ashwagandha can we take per day?
10. Is it better to take ashwagandha in the morning or at night?
11. How do we choose an ashwagandha supplement?
12. Can ashwagandha cause side effects or interact with medications?
13. Frequently asked questions
14. Final thoughts

Ashwagandha (Withania somnifera) is a plant with a long history of use in traditional Ayurvedic medicine. Today, it is commonly found in supplements marketed for stress, sleep, anxiety, and physical performance.

Most modern research has focused on root extracts or extracts made from both the root and leaves. Results are particularly promising for stress and sleep, but the available studies are still relatively small and have used different extracts and doses.

What is ashwagandha and where does it come from?

Ashwagandha is an evergreen shrub known scientifically as Withania somnifera. It grows in parts of India, Africa, and the Middle East and is also cultivated in other regions with suitable climates.

The root has been used for thousands of years in traditional Ayurvedic medicine.

Ashwagandha is sometimes called Indian ginseng or winter cherry, although it does not belong to the ginseng family.

Modern supplements most commonly use root extract, but some products combine extracts from both the root and leaves.

What does ashwagandha contain?

Ashwagandha contains many naturally occurring plant compounds.

Among the most extensively studied are withanolides, a group of compounds believed to contribute to many of the biological effects being investigated.

The chemical composition of the root and leaves is not identical. This means that two ashwagandha supplements can contain different combinations and concentrations of active compounds.

Researchers are investigating how these compounds may influence the body’s response to stress, sleep, and other processes.

However, the exact mechanisms responsible for ashwagandha’s effects in humans are not yet fully understood.

What benefits of ashwagandha have been studied?

Ashwagandha is promoted for a wide range of benefits, but the evidence is not equally strong for all of them.

The most promising research currently focuses on:

• perceived stress;
• certain symptoms of anxiety;
• sleep quality and duration.

Researchers have also investigated possible effects on:

• physical performance;
• memory and cognitive function;
• male fertility;
• testosterone;
• blood glucose;
• immune function;
• metabolic health.

For many of these uses, however, the available evidence is still too limited for firm conclusions.

Another important issue is that clinical studies use different extracts, concentrations, and doses. A result obtained with one specific extract should not automatically be attributed to every ashwagandha supplement.

Can ashwagandha help with stress and anxiety?

Stress is one of the most extensively studied uses of ashwagandha.

Several clinical studies have found that people taking certain ashwagandha extracts for approximately 6–8 weeks reported lower levels of perceived stress.

Some studies have also observed reductions in cortisol, a hormone involved in the body’s stress response.

A 2024 systematic review and meta-analysis also reported favorable findings for stress and anxiety. However, the included studies differed in the extracts and doses used and in the characteristics of participants.

For stress, the results are promising.

For anxiety disorders, the evidence is less clear, and ashwagandha should not be considered a replacement for treatment recommended by a qualified healthcare professional.

Can ashwagandha improve sleep?

Some studies suggest that ashwagandha may have a modest effect on sleep.

Clinical trials using certain extracts have reported improvements in:

• sleep quality;
• total sleep time;
• the time needed to fall asleep.

A review of several studies found that the effects appeared more noticeable in people with insomnia. Results also tended to be better in studies lasting at least eight weeks.

However, the number of studies remains relatively small.

Ashwagandha can therefore be studied as a possible aid for sleep, but it should not be presented as a proven treatment for every type of sleep problem.

Can ashwagandha support physical performance?

Ashwagandha is also found in supplements marketed for exercise and sports performance.

Studies have investigated possible effects on:

• endurance;
• strength;
• recovery;
• exercise capacity.

A 2026 systematic review and meta-analysis reported a possible benefit for some measures of physical performance, with the findings appearing more consistent for aerobic endurance.

Effects on strength were less certain, and evidence for other performance outcomes was limited.

These findings do not mean that ashwagandha acts like a stimulant that immediately increases energy.

If there is an effect on physical performance, the available research suggests that it occurs in the context of regular use of specific extracts, rather than as an immediate response to a single dose.

Overall evidence for athletic performance is still considered insufficient for firm conclusions.

What other effects of ashwagandha are being studied?

Researchers have also examined ashwagandha for possible effects on:

• memory and concentration;
• male fertility;
• testosterone;
• blood glucose;
• immune function;
• metabolic health.

There is some limited evidence that certain preparations taken for approximately 2–4 months may influence testosterone levels and sperm quality in some men.

For many of the other proposed uses, however, there is not yet enough evidence to establish a clear clinical benefit.

A long list of claims on a supplement label should therefore not be confused with a list of benefits proven in clinical trials.

How long does ashwagandha take to work?

Ashwagandha should not generally be viewed as a supplement with an immediate effect.

In studies of stress and sleep, researchers typically assessed results after several weeks of regular use.

Many stress studies lasted approximately 6–8 weeks, while sleep benefits appeared more evident in some studies lasting at least eight weeks.

This does not mean that everyone will notice an effect after the same number of days.

Results may depend on:

• the extract used;
• the dose;
• the reason for taking ashwagandha;
• individual characteristics.

There is therefore no universal amount of time after which ashwagandha should begin to work.

How much ashwagandha can we take per day?

Unlike vitamins and minerals, ashwagandha does not have an official recommended daily intake.

Clinical studies have used very different products.

Research on stress, for example, has included doses of several hundred milligrams of extract per day, while other studies have tested larger amounts or products with different withanolide concentrations.

This makes comparing supplements by milligrams alone potentially misleading.

300 mg of one standardized extract is not necessarily equivalent to 300 mg of another extract or to 300 mg of powdered ashwagandha root.

The relevant factors include:

• the part of the plant used;
• whether the product contains powder or extract;
• the type of extract;
• the concentration of withanolides;
• the reason for using the supplement.

There is no single dose that is appropriate for every person and every ashwagandha product.

Is it better to take ashwagandha in the morning or at night?

There is no official rule stating that ashwagandha must be taken only in the morning or only at night.

The timing may depend on the product, the reason for taking it, and individual tolerance.

Because ashwagandha can cause drowsiness in some people, evening use may be more suitable for them.

For others, the time of day may matter less than taking the product consistently according to its instructions.

If ashwagandha causes stomach discomfort, the product directions should be followed, and persistent symptoms should be discussed with a doctor or pharmacist.

The important point is that there is no single “perfect time” that applies to every ashwagandha extract.

How do we choose an ashwagandha supplement?

Ashwagandha supplements are not all the same.

Some contain powdered root, some contain root extract, while others combine extracts from the root and leaves.

Extracts can also contain different concentrations of withanolides.

When comparing products, it can be useful to check:

What to check	Why it matters
Part of the plant used	Products may contain root, leaves, or a combination
Powder or extract	A concentrated extract is not equivalent to ordinary root powder
Amount per serving	Shows how much of the ingredient the product provides
Withanolide standardization	Helps identify the concentration of these studied compounds
Other ingredients	Products may contain additional active ingredients
Manufacturer instructions	Dosing and use can differ between extracts

A higher number of milligrams does not automatically mean a better product.

When comparing supplements, the type and concentration of the extract matter in addition to the number of milligrams listed on the label.

Can ashwagandha cause side effects or interact with medications?

Yes.

Ashwagandha is a plant, but that does not mean it is free of side effects.

In clinical studies, short-term use — up to approximately three months — has generally been well tolerated.

However, there is not enough information to establish the safety of using ashwagandha continuously for many months or years.

Reported side effects include:

• drowsiness;
• nausea;
• stomach discomfort;
• loose stools or diarrhea;
• vomiting.

Rare cases of liver injury have also been reported in association with supplements containing ashwagandha.

Ashwagandha may also affect thyroid function and can potentially interact with medications used for:

• thyroid conditions;
• diabetes;
• blood pressure;
• sedation;
• seizures;
• suppression of the immune system.

NCCIH advises avoiding ashwagandha during pregnancy and breastfeeding. It is also not recommended for people who are about to undergo surgery or who have certain thyroid or autoimmune conditions.

People who take regular medications or have a medical condition should speak with a doctor or pharmacist before starting an ashwagandha supplement.

Written by Victoria, founder and editor of RoutineHealth. This article is for general education and is not medical advice. If you take medications, have a thyroid, autoimmune, liver, blood pressure, or blood sugar condition, are pregnant or breastfeeding, are preparing for surgery, or are considering ashwagandha for a child, speak with a qualified healthcare professional before using a supplement. How we research and correct articles is explained in our Editorial Policy; see also our Medical Disclaimer.

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