How long does ashwagandha take to work? What the trials measured

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Ashwagandha is not a supplement you feel an hour after taking it. The human trials that reported lower stress scores, lower cortisol or better sleep measured those results after weeks of daily use. None of them tested what happens after a single dose.

This article sets out what the published trials measured and when, so you can judge how long a fair trial of your own should run and when it makes sense to stop.

The short answer

Most trials ran for six to ten weeks. The earliest point at which a trial in our reading measured stress was four weeks. A reasonable expectation is that any effect builds gradually over the first month and is assessed properly at about eight weeks. If you notice nothing by then, the research gives no reason to think that more time will change that.

What each trial measured, and when

Goal	Trial	Daily amount	Length	When results were measured
Stress	64 adults with chronic stress (2012)	300 mg root extract, twice daily	60 days	Day 60
Stress	60 stressed adults (2019)	125 mg or 300 mg root extract, twice daily	8 weeks	Weeks 4 and 8
Stress, cortisol	60 stressed adults (2019)	240 mg root and leaf extract, once daily	60 days	Over 60 days
Sleep quality	150 adults with unrefreshing sleep (2020)	120 mg root and leaf extract, once daily	6 weeks	Week 6
Insomnia	60 adults with insomnia (2019)	300 mg root extract, twice daily	10 weeks	Weeks 5 and 10
Strength training	57 men new to lifting (2015)	300 mg root extract, twice daily	8 weeks	Week 8

Two things stand out. Every trial used daily dosing for at least six weeks. And the outcome was measured at the end, or at one midpoint. That design tells you whether something changed by week eight. It cannot tell you on which day the change began.

Stress: plan on four to eight weeks

The trial most useful for timing is the 2019 study of 60 adults with high scores on a standard perceived stress questionnaire. Participants took 125 mg of root extract twice daily, 300 mg twice daily, or a placebo, for eight weeks. Stress scores were recorded at the start, at four weeks and at eight weeks. Cortisol was measured at the start and at eight weeks.

Both ashwagandha groups had lower stress scores than the placebo group, and the difference was larger at the higher dose. Cortisol fell in both ashwagandha groups by the end of the study.

The 2012 trial of 64 adults with chronic stress used 300 mg twice daily for 60 days and assessed outcomes on day 60. Scores on every stress questionnaire, and blood cortisol, were lower in the ashwagandha group than in the placebo group.

A third trial used a different extract, made from root and leaf, at 240 mg once daily for 60 days. It reported a larger fall in an anxiety rating scale and in morning cortisol than placebo. A second questionnaire in the same study showed a difference that did not reach statistical significance.

A 2022 meta-analysis pooled 12 trials with 1,002 participants. It found lower stress and anxiety scores with ashwagandha than with placebo and reported the clearest effect on stress at 300 mg to 600 mg a day. The authors rated the certainty of the evidence as low, because the trials were small and their results varied widely.

What this means in practice: take it daily, at a dose in the studied range, for eight weeks before you decide. A week is too short to judge.

Sleep: six to ten weeks

Two trials looked at sleep. In the first, 150 adults who reported unrefreshing sleep took 120 mg of a root and leaf extract once daily for six weeks. Self-rated sleep quality improved by 72 percent in the ashwagandha group and by 29 percent in the placebo group. Wrist monitors recorded better sleep efficiency and total sleep time than in the placebo group.

In the second, 60 adults with insomnia took 300 mg of root extract twice daily, or a placebo, for ten weeks. Sleep was assessed at five and ten weeks. Both groups fell asleep faster as the study went on. After ten weeks the ashwagandha group fell asleep faster than the placebo group, by about five minutes on average.

That second result is worth reading twice. The placebo group improved too. Much of what people notice in the first weeks of any sleep supplement is the effect of paying attention to sleep. The difference attributable to ashwagandha was real in that trial but modest.

Ashwagandha is not a sedative in the way melatonin signals bedtime. If you want something for tonight, it is the wrong ingredient. See how long melatonin takes to work for that comparison.

Strength and recovery: eight weeks, with training

One trial randomized 57 men aged 18 to 50 with little lifting experience to 300 mg of root extract twice daily or a placebo. Both groups followed the same resistance training program for eight weeks. The ashwagandha group gained more on the bench press and leg extension than the placebo group.

The participants were beginners, who gain strength quickly on any program, and the study was small. The result has not been established in trained lifters. It also says nothing about ashwagandha without training.

Can you feel it on the first day?

Some people report feeling calmer or drowsier within hours. No trial we read measured a single dose against placebo, so there is no evidence either way. Drowsiness is a recognized side effect, and it can appear early. Feeling sleepy after a dose is not the same thing as the stress result the trials reported.

Be cautious about any product page that promises a fast effect. The research supports a slow one.

What changes the timeline

The dose

The stress trials used 250 mg to 600 mg of root extract a day, and the larger dose performed better in the one trial that compared two doses. A gummy with 50 mg of unspecified ashwagandha is not the product that was studied. Check the amount per gummy and the number of gummies per day. Our guide to per gummy versus per serving shows how to do the arithmetic.

The extract

Extracts differ. A root-only extract studied at 600 mg a day and a root and leaf extract studied at 120 mg to 240 mg a day are not interchangeable by weight. The label should name the extract and the plant part. We compare the three most common ones in KSM-66 vs Sensoril vs Shoden.

Taking it every day

Every trial used daily dosing. Taking ashwagandha only on stressful days is a pattern nobody has tested.

Where you start

The stress trials enrolled adults who scored high on stress questionnaires. Someone with little stress to begin with has less room to change.

How to run a fair eight-week trial of your own

1. Check that it is suitable for you. Ashwagandha is not for everyone. Read who should not take ashwagandha first, and speak to your doctor if you take any regular medication.
2. Pick a product that states the extract and the milligrams. Compare it with the amounts in the table above.
3. Write down a baseline. Rate your stress and your sleep from 1 to 10 each evening for a week before you start.
4. Take it daily as the label directs. Do not exceed the label.
5. Keep rating. Compare weeks 4 and 8 with your baseline week.
6. Decide at eight weeks. No change means it is not doing enough to justify the cost.

A written rating matters because the placebo groups in these trials improved as well. Memory is a poor judge of gradual change.

How long is it safe to continue?

The NIH says ashwagandha appears to be well tolerated for up to about three months, and that its long-term safety is not known. That is the length of the trials, not a measured limit. Many people take a break after two or three months for that reason.

There is one timing fact on the safety side to know. A case series of five people with liver injury attributed to ashwagandha supplements found that symptoms began two to twelve weeks after they started. All had jaundice. Such cases are rare, and the injuries in that series resolved after the supplement was stopped. Stop taking ashwagandha and see a doctor if you develop yellowing of the skin or eyes, dark urine, persistent itching or unexplained nausea.

How one gummy label compares

As an example of reading a label against the trials: the Supplement Facts panel for Goli Ashwagandha Gummies lists 150 mg of KSM-66 ashwagandha root extract per gummy, with a suggested use of two gummies twice daily. That is 600 mg a day, the same daily amount of the same named extract used in several of the trials above. Four gummies also supply 8 g of sugars. Our Goli Ashwagandha Gummies review goes through the full label.

The ashwagandha ingredient guide covers the research in more depth, and all the stress-related reviews are on the stress gummies page.

The short version

• Trials measured results at four to ten weeks. None tested a single dose.
• For stress, allow eight weeks of daily use at 250 mg to 600 mg of root extract.
• For sleep, allow six to ten weeks, and expect a modest change.
• The evidence is rated low certainty. The trials are small.
• If nothing has changed by eight weeks, stop.
• Safety is studied only to about three months.

Common questions

How long does ashwagandha take to work for stress?

Trials measured lower stress scores after four to eight weeks of daily use. Plan on eight weeks before judging.

Does ashwagandha work right away?

No trial has tested a single dose. Some people feel drowsy soon after taking it, which is a side effect and not the outcome the trials measured.

How long does ashwagandha take to lower cortisol?

The trials that measured cortisol did so after about eight weeks of daily use and reported lower levels than with placebo.

How long does ashwagandha take to help sleep?

Sleep trials ran for six and ten weeks. The improvement over placebo was modest.

What if I feel nothing after two months?

Stop. The trials give no reason to expect a later effect, and the supplement costs money and adds sugar.

Can I take ashwagandha for longer than three months?

Its safety beyond about three months has not been studied. Ask your doctor before continuing long term.

Sources

1. Salve J, et al. Adaptogenic and anxiolytic effects of ashwagandha root extract in healthy adults: a double-blind, randomized, placebo-controlled clinical study. Cureus. 2019.
2. Chandrasekhar K, et al. A prospective, randomized double-blind, placebo-controlled study of safety and efficacy of a high-concentration full-spectrum extract of ashwagandha root in reducing stress and anxiety in adults. Indian J Psychol Med. 2012.
3. Lopresti AL, et al. An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: a randomized, double-blind, placebo-controlled study. Medicine (Baltimore). 2019.
4. Akhgarjand C, et al. Does ashwagandha supplementation have a beneficial effect on the management of anxiety and stress? A systematic review and meta-analysis of randomized controlled trials. Phytother Res. 2022.
5. Deshpande A, et al. A randomized, double blind, placebo controlled study to evaluate the effects of ashwagandha (Withania somnifera) extract on sleep quality in healthy adults. Sleep Med. 2020.
6. Langade D, et al. Efficacy and safety of ashwagandha (Withania somnifera) root extract in insomnia and anxiety: a double-blind, randomized, placebo-controlled study. Cureus. 2019.
7. Wankhede S, et al. Examining the effect of Withania somnifera supplementation on muscle strength and recovery: a randomized controlled trial. J Int Soc Sports Nutr. 2015.
8. Björnsson HK, et al. Ashwagandha-induced liver injury: a case series from Iceland and the US Drug-Induced Liver Injury Network. Liver Int. 2020.
9. NIH National Center for Complementary and Integrative Health. Ashwagandha: usefulness and safety.
10. NIH Office of Dietary Supplements. Ashwagandha: is it helpful for stress, anxiety, or sleep? Fact sheet for health professionals.

These statements have not been evaluated by the Food and Drug Administration. Products discussed here are not intended to diagnose, treat, cure or prevent any disease. This page is not medical advice. It is written for adults 18 and over.