Ashwagandha: benefits according to the research
Ashwagandha (Withania somnifera) has been used for over 3,000 years in Indian tradition. But tradition is not evidence. Here we go through what modern clinical studies actually show – and what you can expect if you start taking it.
What is ashwagandha?
Ashwagandha is a shrub that grows in India, the Middle East and parts of Africa. It is the root that is used in supplements. It contains withanolides, a group of compounds linked to the herb's effects.
Research almost always uses standardised root extract, not raw powder. KSM-66 is the most researched extract, with more than 20 clinical studies behind it. It is also the form in our ashwagandha with 500 mg of KSM-66 per capsule.
Ashwagandha is often called an adaptogen. The word describes herbs believed to help the body cope with stress. The concept is debated among researchers, but the studies on ashwagandha specifically are of high quality compared with many other herbs.
What effects does ashwagandha have according to the research?
The strongest evidence is for stress, sleep and recovery. There are also interesting results on strength and hormone levels in men. The table shows the most cited studies.
| Area | Study | Result |
|---|---|---|
| Stress | Chandrasekhar 2012, 64 participants | Perceived stress −44 %, cortisol −27.9 % |
| Sleep | Langade 2019, 60 participants | Fell asleep faster, better sleep quality |
| Strength | Wankhede 2015, 57 men | Greater strength gains than placebo |
| Anxiety | Pratte 2014, systematic review | Lower anxiety levels in several studies |
| Testosterone | Lopresti 2019, 57 men aged 40–70 | +14.7 % compared with placebo |
Ashwagandha and stress
Stress is the area where the evidence is clearest. In a 2012 study, 64 people with chronic stress received either 600 mg of KSM-66 per day or placebo for 60 days. The group taking ashwagandha reduced their perceived stress by 44 percent. Blood cortisol levels dropped by 27.9 percent.
The result has been replicated in several later studies with doses between 240 and 600 mg per day. We cover the mechanisms in detail in our article on ashwagandha and cortisol.
KSM-66 root extract with 500 mg per capsule – GMP-manufactured and third-party tested.
See current price »Does ashwagandha help with sleep problems?
Yes, there is support for this. In a 2019 study, 60 adults with sleep difficulties took 600 mg of KSM-66 per day for ten weeks. They fell asleep faster and rated their sleep quality higher than the placebo group.
A 2021 meta-analysis reviewed five studies with a combined total of around 400 participants. The conclusion: a small but clear improvement in sleep. The effect was greatest in people with diagnosed sleep problems and with at least eight weeks of use.
Worth knowing: ashwagandha is not a sleeping pill that knocks you out in the evening. The improvement instead seems to be linked to a lower stress response – the body finds it easier to wind down on its own. If you already sleep well, you are likely to notice less of a difference.
Does ashwagandha increase strength and muscle mass?
A 2015 study followed 57 young men through eight weeks of strength training. Half took 600 mg of ashwagandha per day, half placebo. The ashwagandha group increased their bench press by an average of 20 kg, versus 10 kg in the placebo group. They also built more muscle mass and recovered faster.
That sounds impressive, and the study is well designed. But more independent studies are needed before firm conclusions can be drawn about the training effect.
Does ashwagandha affect hormones?
In men, there is some support. In a 2019 study of 57 men aged 40 to 70, testosterone increased by 14.7 percent compared with placebo after eight weeks. The increase occurred from normal levels – ashwagandha is not a medicine for testosterone deficiency.
What about the thyroid? In a smaller 2018 study of people with subclinical hypothyroidism, TSH values improved after eight weeks. If you have a thyroid condition or take thyroid hormone, talk to your doctor before starting, as the effect could interfere with your medication.
How long does it take to notice an effect?
Expect 4 to 8 weeks. Most studies measured results after 8 to 10 weeks of daily use. Ashwagandha is not something you feel after an hour, like caffeine. The effect builds up gradually.
The dose matters too. The studies mostly used 600 mg of standardised extract per day. Read more in our guide to the right dose of KSM-66.
What ashwagandha does not do
The limits are just as important as the effects. Ashwagandha does not cure or treat any disease. It is not a medicine for anxiety or depression, and it is no substitute for therapy, sleep hygiene or exercise.
EFSA, the European Food Safety Authority, has so far not approved any health claims for ashwagandha. The studies we describe here are therefore research in progress, not established fact. Be sceptical of shops that promise more.
Reasonable expectations look like this: a somewhat calmer everyday life, slightly better sleep, gradually and after several weeks. Many people find that well worth it. But look for miracles somewhere else.
Is ashwagandha safe?
Most people tolerate ashwagandha well. The most common issues are mild stomach discomfort and drowsiness at the start, usually passing within a week. Pregnant and breastfeeding women should avoid it entirely. If you take medication, ask your doctor or pharmacist first.
We have gathered everything you need to know in our article on ashwagandha side effects. And if you want to compare extracts, doses and prices before buying, you will find our review of the best ashwagandha here on the site.
Frequently asked questions
What does ashwagandha do in the body?
Ashwagandha acts primarily on the body's stress system. In studies, the root extract has lowered levels of the stress hormone cortisol and reduced perceived stress. Participants also report better sleep and more everyday energy. Withanolides, the active compounds in the root, are thought to be behind the effect, but the exact mechanism is still being mapped out.
How quickly do you notice the effect of ashwagandha?
Expect 4 to 8 weeks before you notice a clear difference. In most studies, results were measured after 8 to 10 weeks of daily use. Some participants saw improvements after just a month, but the effect builds up gradually. Taking it daily matters more than the exact time of day.
Can you take ashwagandha every day?
Yes, in the studies ashwagandha was taken daily for 8 to 12 weeks without serious side effects. Long-term data over several years is lacking, however. Many people choose to take a break of a few weeks after two to three months of use. Pregnant or breastfeeding women and people taking medication should talk to a doctor or pharmacist first.
What is KSM-66?
KSM-66 is a standardised extract made solely from ashwagandha root, with a guaranteed withanolide content of at least five percent. It is the world's most studied ashwagandha extract, with over 20 clinical studies behind it. The standardisation means you get the same amount of active compounds in every capsule, which raw powder cannot guarantee.
Sources
- Chandrasekhar K et al. (2012). A prospective, randomized double-blind, placebo-controlled study of ashwagandha root extract in reducing stress and anxiety. Indian J Psychol Med.
- Langade D et al. (2019). Efficacy and safety of ashwagandha root extract in insomnia and anxiety. Cureus.
- Wankhede S et al. (2015). Examining the effect of Withania somnifera supplementation on muscle strength and recovery. J Int Soc Sports Nutr.
- Lopresti AL et al. (2019). A randomized, double-blind, placebo-controlled study examining the hormonal and vitality effects of ashwagandha in aging, overweight males. Am J Mens Health.
- Pratte MA et al. (2014). An alternative treatment for anxiety: a systematic review of human trial results for ashwagandha. J Altern Complement Med.
- Cheah KL et al. (2021). Effect of ashwagandha extract on sleep: a systematic review and meta-analysis. PLoS One.
- Sharma AK et al. (2018). Efficacy and safety of ashwagandha root extract in subclinical hypothyroid patients. J Altern Complement Med.
- Swedish Food Agency – on food supplements.