Ashwagandha (Withania somnifera) is a root used in Ayurveda and sold today mostly as a standardised extract. Small trials of 8 to 12 weeks support modest effects on perceived stress and on sleep. Evidence for most other claims is thin. It should be avoided in pregnancy, and people with thyroid or liver conditions should check with a doctor first.
| What it is | Root of Withania somnifera, a shrub native to India |
|---|---|
| Active compounds | Withanolides |
| Common forms | Root powder (churna), tablets, extract capsules |
| Amounts used in trials | 240 to 600 mg of root extract a day |
| How long trials ran | 8 to 12 weeks |
| Main cautions | Pregnancy, thyroid conditions, liver conditions, sedatives |
And how good the evidence is.
| Taken for | Evidence | What the studies show |
|---|---|---|
| Stress | Moderate | Several small placebo-controlled trials of 8 to 12 weeks report lower perceived-stress scores and lower cortisol with root extract. |
| Sleep | Some | A smaller group of trials reports better sleep quality, mainly in people who were sleeping badly to begin with. |
| Strength and recovery | Early | A few small studies alongside resistance training. Interesting, not yet convincing. |
| Immunity | None | Widely claimed on labels. We found no human evidence worth quoting. |
Grades are our reading of published human trials on the ingredient, not tests of this product. Moderate: several controlled trials agree. Some: a few do. Early: small or preliminary. Traditional: long use, little trial data. None: nothing worth quoting. How we grade evidence
Taken from real searches in India.
Possibly, if you sleep badly. In a 10-week trial of 60 people with insomnia, 300 mg of root extract twice a day shortened the time taken to fall asleep and improved sleep efficiency compared with placebo. That is one small trial, so we grade the evidence as "some", not strong.
Two placebo-controlled trials of about 60 adults each, run for 60 days, reported lower cortisol and lower stress scores with root extract. The trials were small and short, and both used specific branded extracts.
The evidence is mixed. An 8-week trial in 57 young men doing resistance training reported a larger rise in testosterone with ashwagandha than with placebo. A separate 60-day trial found the change in men was not significantly different from placebo. It is not an established effect.
The stress and sleep trials included both men and women and found similar results. The strength and testosterone studies were done in men only. There is no good evidence of benefits specific to women, and pregnant women should not take it.
Trials gave it daily for 8 to 12 weeks. The US National Center for Complementary and Integrative Health says it may be safe for up to about three months, and that long-term safety is not known.
No trial has compared morning with night. Studies gave it once or twice a day, usually with food. People taking it for sleep often take it in the evening. Taking it at the same time each day matters more than the hour.
Yes. Taking it with warm milk is the traditional way, and one sleep trial gave capsules with either milk or water. There is no evidence that milk changes how well it works.
It can, but stomach upset is one of the more common side effects. If it bothers you, take it with food.
Most trials used 240 to 600 mg a day of standardised root extract. Root powder is a different product and is traditionally taken in gram amounts. We do not give personal dosing advice; follow the label and ask a doctor if you take medicines.
There is no good evidence that it meaningfully changes body weight in either direction. In one trial, men who trained with weights lost slightly more body fat with ashwagandha, but that is not a reason to buy it for weight.
There is no controlled human evidence either way. Claims in both directions come from anecdotes.
Ayurveda classifies ashwagandha as a warming herb. That is a traditional description, not something clinical trials have measured.
Powder is the dried, ground root. Tablets may contain either powder or extract. Extract concentrates the root to a stated withanolide level, which is what most trials used. They are not interchangeable gram for gram, so check which one the label describes.
KSM-66 is a branded ashwagandha root extract made by one Indian manufacturer and used in several clinical trials. A brand name is not a test result. Whatever the extract, look for the plant part, the withanolide percentage and the method used to measure it.
They are different things. Ashwagandha is a plant root; shilajit is a mineral-rich resin. Ashwagandha has more human trials behind it. Neither is a substitute for the other.
Drowsiness, stomach upset and loose stools are the most reported. Rare cases of liver injury have been described. It may also change thyroid hormone levels and can add to the effect of sedatives.
It may lower blood sugar slightly and could add to the effect of diabetes medicines. Anyone on such medicines should ask their doctor before taking it.
Avoid it during pregnancy and breastfeeding. People with thyroid disease, liver disease or autoimmune conditions, people due for surgery, and anyone on regular medication should check with a doctor first.
Skeptics Ashwagandha Root Extract500 mg · 5% withanolides by HPLC · root only60 vegetarian capsules · ₹649See the specificationWhichever brand you choose, check the plant part, the active-compound percentage, the method used to measure it, and the heavy-metal results for the batch.
This guide is general information about an ingredient, not medical advice and not a claim about any product. Research on an ingredient is not a clinical trial of a particular supplement. Speak to a doctor before taking any supplement if you are pregnant, breastfeeding, have a medical condition or take medicines.