Ashwagandha now turns up in gummies, coffees and bedtime drinks. A handful of small trials look promising for stress, but it’s an active herb with side effects and good reasons some people should skip it.
The evidence in brief
- Small clinical trials, mostly six to eight weeks long, suggest ashwagandha root extract may modestly lower stress and anxiety; evidence for sleep is thinner.
- It appears safe for most adults for up to about three months, but drowsiness and stomach upset are common, and rare cases of liver injury have been reported.
- Skip it if you’re pregnant or breastfeeding or have hormone-sensitive prostate cancer, and ask a doctor first if you take thyroid medicine, sedatives or drugs that suppress the immune system.
- ‘Adaptogen’ isn’t a medical or regulatory category. It’s a traditional and marketing label covering herbs with very different levels of evidence.
Ashwagandha (Withania somnifera) is a small shrub whose root has been used in Ayurvedic medicine for centuries. In the U.S. it has become one of the best-selling herbal supplements, sold as capsules, powders, gummies and an ingredient in drinks with names like “Calm” and “Unwind.” It’s also the most studied of the herbs marketed as adaptogens, which makes it a good place to start.
What the studies say about stress and sleep
Most of the human research comes from small randomized trials, many of them run in India, lasting six to eight weeks. Participants typically took 250 to 600 milligrams a day of a root extract. In several of these trials, people taking ashwagandha reported lower stress and anxiety scores than people taking a placebo, and some showed lower levels of cortisol, a stress hormone.
That’s more than many supplements can show. But the NIH’s Office of Dietary Supplements points out real limits:
- The trials are small and short.
- They used different extracts at different doses, so results don’t transfer neatly to the product on your shelf.
- Some were funded by companies that sell those extracts.
- Evidence that ashwagandha improves sleep is weaker than for stress.
Side effects, and the liver question
In studies, the most common complaints are drowsiness, upset stomach and loose stools. Less common, but more serious, are reports of liver injury in people taking ashwagandha supplements. These cases are rare and most people recovered after stopping, but they’re a reason to stick to the labeled dose.
Safety first
Stop taking ashwagandha and contact a doctor if you notice yellowing of your skin or eyes, dark urine, itching, unusual tiredness or pain in the upper right side of your abdomen.
Ashwagandha may also raise thyroid hormone levels and testosterone levels, which matters for the groups below.
Who should skip it or ask first
Avoid it if you:
- are pregnant, since it may not be safe in pregnancy, or breastfeeding, since it hasn’t been studied
- have hormone-sensitive prostate cancer
- have liver disease or have had liver problems from a supplement before
Talk to a doctor or pharmacist first if you:
- have a thyroid condition or take thyroid medication
- take sedatives, sleep aids or anxiety medication
- take medicines for diabetes or blood pressure, since it may add to their effects
- take drugs that suppress the immune system, or have an autoimmune condition
- have surgery scheduled
The other “adaptogens”
The word has been around since the mid-1900s, used to describe substances thought to help the body resist stress. It isn’t an FDA category, and no rule defines which products can use it. Herbs sold under the label vary a lot:
| Herb | Usual claim | What the evidence looks like |
|---|---|---|
| Rhodiola | Less fatigue and stress | A few small studies with mixed results |
| Asian and American ginseng | Energy, focus | Mixed; can lower blood sugar and may interact with warfarin |
| Holy basil (tulsi) | Stress relief | Very little good human research |
| Mushroom blends such as reishi or lion’s mane | Calm, focus, immunity | Mostly laboratory and animal studies so far |
A product that combines several of these at undisclosed amounts, often listed as a “proprietary blend,” makes it impossible to know how much of each you’re taking.
If you decide to try it
- Run it past your doctor or pharmacist if you take any prescription medicine.
- Choose a product that names the extract and the dose, and that has independent testing such as a USP or NSF seal.
- Stay at or below the label dose, and watch for doubling up when “calm” drinks and gummies contain it too.
- Keep it to a few months, which is about as long as it has been studied.
- Don’t let it stand in for treatment. If anxiety or poor sleep is affecting your daily life, talk to a doctor; there are well-tested options.
For help judging any supplement label, see our guide to reading wellness claims. If stress relief is the goal, our look at massage therapy covers an option with more research behind it.
Asked and answered
How long does ashwagandha take to work?
Studies usually measure effects after several weeks of daily use. If you notice nothing after about two months, it probably isn’t doing much for you.
Can I take it with antidepressants or anxiety medicine?
Check with your doctor or pharmacist first. Ashwagandha can cause drowsiness and may add to the effects of sedating medicines, and it hasn’t been well studied alongside many common drugs.
Are ashwagandha gummies as good as capsules?
Gummies often contain lower or unclear doses, plus sugar. Whatever the form, check how much extract is in a serving and look for independent testing.
This guide is general information, not medical advice. Check with your doctor or pharmacist before starting a supplement, device or treatment, especially if you’re pregnant, take medicines or have a health condition.