Ashwagandha: Health Benefits, Side Effects, and Research | Hardworkout Magazine

Key takeaways

- A 2023 systematic review reported that doses of 250–500 mg of ashwagandha daily for 4–13 weeks reduced cortisol levels in people with elevated stress.

- Ashwagandha's effect on sleep is greatest in people who already have sleep problems and when used for at least eight weeks, according to a meta-analysis of around 400 participants.

- Studies showing positive results typically use standardised extracts such as KSM-66, Sensoril or Shoden, so results cannot be transferred directly to every ashwagandha product on the market.

- Ashwagandha is generally well tolerated by healthy adults, but pregnant women are advised to avoid it, and people with diabetes, high blood pressure or medication for anxiety or sleep problems should consult a doctor first.

In recent years, ashwagandha has appeared increasingly often in online stores, pharmacies, and on social media. The supplement is often referred to as an ancient medicinal plant with a long history, but interest in ashwagandha has also surged outside the circles that have traditionally used herbal medicine.

Popularity has grown rapidly, but many still know little about what ashwagandha actually is. Therefore, it is worth taking a closer look at both the plant and the research that has contributed to the increasing interest.

What is ashwagandha, and which compounds matter?

Ashwagandha (Withania somnifera) is a plant that has been used in Ayurvedic medicine for several thousand years.

It grows naturally in parts of Asia, the Middle East, and North Africa, and is today used as a dietary supplement in many parts of the world. Although the plant is often referred to as "Indian ginseng", it is not related to the ginseng plant.

In dietary supplements, the root is mainly used, either as powder or concentrated extracts.

The root contains a number of natural plant compounds, including alkaloids, flavonoids, and a group of substances called withanolides. It is particularly the withanolides that have attracted attention in research.

Much of the research on ashwagandha has therefore focused on these substances and what significance they may have for the effects observed in studies.

Ashwagandha is often referred to as an adaptogen, a term used for plants that are believed to influence the body's ability to handle physical and mental stress. Ginseng and rhodiola are also often placed in this category.

The term is widely used in marketing, but in itself says little about effect. What is interesting is therefore not what the plant is called, but what the research actually shows.

Why has ashwagandha suddenly become so popular?

Many supplements target a specific goal. Protein powder is associated with muscle growth, creatine with strength, and caffeine with increased alertness.

Ashwagandha has gained attention for a different reason. The interest is primarily due to research on stress, sleep, and mental health – areas that affect far more than just people who work out.

In recent years, a number of clinical studies have examined how ashwagandha affects stress-related issues. A [systematic review and dose-response meta-analysis](https://www.sciencedirect.com/science/article/pii/S0965229926000087) published in 2026 gathered data from 22 randomized controlled trials with a total of 1391 participants.

The researchers found that individuals using ashwagandha consistently reported less stress, fewer anxiety symptoms, and fewer depressive symptoms than those receiving a placebo.

At the same time, it is important to look at the bigger picture. The researchers rated the quality of the evidence as low to very low. The reasons included significant differences between the studies, varying doses, different extracts, and variation in the participants included.

The results point in a positive direction, but the differences between the studies make it difficult to draw firm conclusions about how significant the effect actually is.

Nevertheless, this is likely an important part of the explanation for its popularity. Many do not use ashwagandha to perform better in training, but because they want less stress, better sleep, and more energy in everyday life.

What does ashwagandha do to stress, sleep and cortisol?

Research is most extensive on stress and sleep.

When the body is exposed to stress, several systems are activated to help us cope with challenges. One of the most important is the HPA axis, which regulates the production of hormones like cortisol.

Cortisol is often referred to as the body's stress hormone, but the hormone has far more functions than that. It contributes, among other things, to regulating energy availability, blood sugar, immune defense, and circadian rhythm.

Cortisol is therefore not a hormone that is harmful in itself. The problem arises when stress becomes prolonged and levels remain elevated over time. This is linked to poorer sleep, increased fatigue, concentration problems, and a greater risk of anxiety and depression.

Several studies have investigated whether ashwagandha affects cortisol levels. A [systematic review](https://link.springer.com/article/10.1186/s12986-025-00902-7) published in 2023 found that doses of 250–500 mg daily for 4–13 weeks reduced cortisol levels in individuals with elevated stress levels.

This does not necessarily mean that cortisol alone explains the observed effects, but it may be part of the explanation for why ashwagandha appears to influence both stress and sleep.

Sleep is another area where research points in a positive direction. A [meta-analysis](https://link.springer.com/article/10.1186/s12986-025-00902-7) with around 400 participants found that individuals using ashwagandha slept better, slept longer, and took less time to fall asleep than those who received a placebo. The effect was greatest among individuals who already had sleep problems and with use over at least eight weeks.

Researchers have also investigated possible mechanisms behind these findings. Some research suggests that compounds in ashwagandha may affect the GABA system in the brain.

GABA is a neurotransmitter that helps to dampen activity in the nervous system and plays an important role in relaxation and sleep.

However, much of the research in this area comes from laboratory and animal studies, and it is still uncertain how significant these mechanisms are in humans.


What other health effects has ashwagandha been studied for?

Although stress and sleep are the areas with the best documentation, [research](https://iadns.onlinelibrary.wiley.com/doi/10.1002/efd2.70061) has also investigated a number of other potential health effects.

One area that has received a lot of attention is oxidative stress. This describes an imbalance between the formation of reactive compounds in the body and the body's ability to neutralize them with the help of antioxidants.

Several studies suggest that ashwagandha may strengthen the body's own antioxidant defense. Researchers have observed increased activity of enzymes that protect cells against oxidative stress, while some studies have reported fewer signs of oxidative damage in the cells.

Researchers have also investigated how ashwagandha affects the body's inflammatory response.

In some studies, lower levels of CRP, a marker often used to measure inflammation in the body, have been reported. This has made ashwagandha interesting in research on metabolic health and other conditions where inflammation may play a role.

Another area of research is metabolic health. Several studies have examined how ashwagandha affects blood sugar and the body's response to insulin.

The results point to better blood sugar control and increased insulin sensitivity in certain groups, but the research base is currently much smaller than for stress and sleep.

Ashwagandha has also been studied in relation to brain function.

Some studies have reported improvements in memory, attention, reaction time, and the ability to process information.

The clearest results have been seen in individuals with mild cognitive impairment, where participants performed better on several tests of memory and concentration than those who received a placebo.

Does ashwagandha improve strength and performance?

Although this is not the main reason why ashwagandha has become popular, there is also research on physical performance.

A recent [review article](https://iadns.onlinelibrary.wiley.com/doi/10.1002/efd2.70061) found that ashwagandha in several studies was associated with improvements in maximum strength, explosiveness, VO₂max, and certain measures of recovery. Several studies also reported greater progress in strength exercises such as bench press and squats compared to placebo.

Some studies have also found moderate increases in testosterone levels.

However, researchers do not know whether this is due to a direct effect on hormone production, or if it is an indirect consequence of lower stress levels, better sleep, and reduced cortisol.

The researchers behind the review article also emphasize that the number of studies on trained individuals is still limited.

It is therefore still unclear how significant ashwagandha is for strength and physical performance.

Why do ashwagandha products differ so much?

A challenge when evaluating research on ashwagandha is that the studies do not necessarily use the same products that are available on store shelves.

Many of the studies with positive results have been conducted with standardized extracts such as [KSM-66,](https://hardworkout.no/KSM66-ashwagandha) [Sensoril](https://hardworkout.no/vitaprana-sensoril-ashwagandha) or Shoden.

Standardization means that the content of specific compounds is controlled and documented. This makes it easier for researchers to know what participants are actually consuming.

Two products that are both sold as ashwagandha can therefore contain very different amounts of the substances being studied in the research.

Results from one study cannot therefore be directly applied to all products on the market.

Who Should Be Cautious?