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How long does ashwagandha take to work?

Written by the Full Measure editorial team, which sells supplements. Approved for publication by the Full Measure owners. Updated .

Drafted with AI assistance from the sources listed below. How we write these

Quick answer

In trials, differences from placebo usually appeared after about 8 weeks of daily use, not in the first days. Where trials checked along the way, stress and sleep scores had not yet separated from placebo at 4 weeks. Most trials ran 6 to 12 weeks, and NIH says safety beyond about 3 months is unknown.1,2,3

Key facts

  • Most of the stress trials NIH reviewed lasted 6 to 8 weeks.3
  • A pooled analysis of sleep trials found larger effects in trials lasting 8 weeks or more.4
  • When liver injury has occurred, it usually began 2 to 12 weeks after starting.5
  • Safety beyond about 3 months of use is not known.3,6

What the trials saw, week by week

In trials that measured along the way, stress scores, cortisol and self-rated sleep quality differed from placebo at week 8 but not yet at week 4.1,2

In a 10-week trial in adults with diagnosed sleep problems, some sleep measures differed from placebo by week 5, while the time taken to fall asleep differed only at week 10.7

When trials checked, and when a difference from placebo first showed1,2,7,8
TrialChecked atFirst difference from placebo
Stress, 60 adults, 250 or 600 mg a dayWeeks 4 and 8Week 8, for stress scores and cortisol
Sleep, 60 adults with diagnosed sleep problemsWeeks 5 and 10Some sleep measures at week 5; time to fall asleep at week 10
Adults aged 65 to 80, 600 mg a dayWeeks 4, 8 and 12Week 8, for sleep quality and alertness on waking
Women footballers, 600 mg a dayDays 14 and 28Sleep quality at day 14; recovery at day 28

These were small trials. A difference that was not significant at week 4 may simply have been too small to detect with about 20 people a group. Still, none of them gives a reason to expect a change within days.1

For sleep, a pooled analysis of five trials found larger effects in trials that lasted 8 weeks or more, and at 600 mg a day or more.4

Anything on the first day?

One trial gave 59 young adults a single 225 mg dose of a root and leaf extract and repeated tests 60 minutes later, then again after 30 days of daily use. Some memory and attention scores changed more than on placebo, but it is one trial of a different extract.9

That trial used 225 mg of a liposomal root and leaf extract, not the root extract most trials gave, so it says little about the first day on a typical product. The other trials did not test single doses at all.3,9

In 30 professional women footballers taking 600 mg a day of root extract, self-rated sleep quality differed from placebo from day 14, and self-rated recovery by day 28.8

How long to keep taking it

NIH says ashwagandha appears well tolerated for up to about 3 months, and that its safety over many months or years is not known.3,6

Most trials ran 6 to 12 weeks, and the 8-week mark was the most common endpoint. The longest we found, in women after menopause, ran 24 weeks. Taking it for many months goes beyond what most of the research has tested, for benefits and for safety alike.3,10

When side effects tend to appear

Liver injury linked to ashwagandha is rare, but when it happens it usually starts 2 to 12 weeks after someone begins taking it, and it most often clears within 1 to 4 months of stopping. The few fatal cases were mainly in people who already had liver disease.5

Stop taking it and see a doctor if you notice yellow skin or eyes, itching, nausea, unusual tiredness or stomach discomfort in the weeks after starting.3,5

Thyroid changes can also take weeks. In one published case, a woman developed signs of an overactive thyroid 6 weeks after starting an ashwagandha product, and her thyroid tests returned to normal soon after she stopped.5

  • Do not take it if you are pregnant or breastfeeding6
  • Ask your doctor first if you have liver disease or a thyroid condition, or take thyroid hormone3,5
  • Talk to your doctor before using it for longer than about 3 months3

Questions people ask

How long does ashwagandha take to work for stress?

The stress trials measured results after 6 to 8 weeks. In the one trial that also checked at 4 weeks, stress scores and cortisol had not yet separated from placebo; they had by week 8.1,3

Does ashwagandha work the same day?

Not in the way most trials measured it. One small trial of a different extract reported some test score changes an hour after a dose, but the main trials measured effects after weeks of daily use.3,9

Can I take ashwagandha for more than 3 months?

NIH says its safety beyond about 3 months is not known, because most trials stopped there. Talk to your doctor before taking it for longer.3,6

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Sources

  1. Salve J, Pate S, Debnath K, Langade D. Adaptogenic and anxiolytic effects of ashwagandha root extract in healthy adults: a double-blind, randomized, placebo-controlled clinical study. Cureus. 2019;11(12):e6466. Opened 2026-10-01.
  2. Kelgane SB, Salve J, Sampara P, Debnath K. Efficacy and Tolerability of Ashwagandha Root Extract in the Elderly for Improvement of General Well-being and Sleep: A Prospective, Randomized, Double-blind, Placebo-controlled Study. Cureus. 2020;12(2):e7083. Opened 2026-10-07.
  3. National Institutes of Health, Office of Dietary Supplements. Ashwagandha: Is it helpful for stress, anxiety, or sleep? Fact Sheet for Health Professionals. Updated May 2, 2025. Opened 2026-10-07.
  4. Cheah KL, Norhayati MN, Husniati Yaacob L, Abdul Rahman R. Effect of ashwagandha (Withania somnifera) extract on sleep: a systematic review and meta-analysis. PLoS One. 2021;16(9):e0257843. Opened 2026-10-01.
  5. LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. Ashwagandha. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases. Last update December 3, 2024. Opened 2026-10-07.
  6. National Center for Complementary and Integrative Health. Ashwagandha. Last updated March 2023. Opened 2026-10-07.
  7. Langade D, Kanchi S, Salve J, Debnath K, Ambegaokar D. Efficacy and Safety of Ashwagandha (Withania somnifera) Root Extract in Insomnia and Anxiety: A Double-blind, Randomized, Placebo-controlled Study. Cureus. 2019;11(9):e5797. Opened 2026-10-07.
  8. Coope OC, Reales Salguero A, Spurr T, et al. Effects of Root Extract of Ashwagandha (Withania somnifera) on Perception of Recovery and Muscle Strength in Female Athletes. Eur J Sport Sci. 2025;25(3):e12265. Opened 2026-10-07.
  9. Leonard M, Dickerson B, Estes L, et al. Acute and Repeated Ashwagandha Supplementation Improves Markers of Cognitive Function and Mood. Nutrients. 2024;16(12):1813. Opened 2026-10-07.
  10. Pingali U, Nutalapati C, Wang Y. Ashwagandha and Shatavari Extracts Dose-Dependently Reduce Menopause Symptoms, Vascular Dysfunction, and Bone Resorption in Postmenopausal Women: A Randomized, Double-Blind, Placebo-Controlled Study. J Menopausal Med. 2025;31(1):21-34. Opened 2026-10-07.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.