Quick answer
No study we found has timed how quickly chamomile acts after a single cup or capsule. Sleep trials compared results after two to four weeks of regular use, and a menopause trial after 12 weeks. In one tea trial, the difference seen at two weeks was gone four weeks after the tea stopped.1,2,3,4
Key facts
- The US sleep trial gave its second daily capsule about an hour before bed, a choice made by the researchers rather than a measured onset time.2
- A nursing home trial checked sleep quality at two weeks, at four weeks, and two weeks after the capsules ended.1
- New mothers who drank chamomile tea for two weeks scored better than usual care at the end of the course, but not four weeks later.3
- The longest trial ran for 38 weeks in total, with side effect rates similar to placebo.5
After one cup or capsule
We found no study in people that measured chamomile's effect in the hours after a single cup of tea or a single capsule, and none that tracked how long its compounds stay in the blood. The idea that it acts quickly comes from tradition and from laboratory and animal work on apigenin, one of its flavonoids.2,6
The closest thing to a timing guide is the schedule researchers chose. In the US sleep trial, the first capsule was taken between lunch and dinner and the second about an hour before bed. That reflects a plan for the trial, not evidence that an hour is how long chamomile needs.2
Over weeks of regular use
| Trial | Daily use | When checked | Result at that point |
|---|---|---|---|
| 60 adults aged 60 or over, extract | 200 mg twice a day | At 2 and 4 weeks, and 2 weeks after stopping | Better sleep quality scores than flour capsules after the course |
| 34 adults, standardized extract | 270 mg twice a day | At 28 days | No significant difference from placebo on sleep diaries |
| 80 new mothers, tea | Chamomile tea for 2 weeks | At 2 weeks, then 4 weeks later | Better scores at 2 weeks, no difference 4 weeks later |
| 80 women after menopause, extract | 100 mg four times a day | At 12 weeks | Lower menopause checklist scores than placebo |
The sleep trials checked results after two to four weeks of use, not after a single dose.1,2,3
Because every trial in the table measured after weeks, not days, they cannot tell whether the changes some of them saw began in the first few nights or built up slowly. The 2024 review of 10 sleep trials also found results varied widely from trial to trial, so a few weeks of use may show nothing at all.7
After you stop
In the tea trial in new mothers, the difference from usual care seen after two weeks of tea was gone four weeks later.3
That is the only trial we found that reported what happened after chamomile ended, and one small trial cannot show how long effects last in general.3
How long people have taken it
The longest trial gave 1,500 mg of extract a day for 12 weeks, then continued it for 26 more weeks in a randomized group, with side effect rates similar to placebo.5
No upper limit has been set for chamomile. NCCIH says it is likely safe in the amounts found in teas and foods, and possibly safe when taken as a supplement over the short term.6
The sleep trials we read lasted two to four weeks. Beyond the one long trial above, there is little information on daily use over many months, so ask your doctor before taking it every day long term, especially if you take warfarin or birth control pills.1,2,3,6
If trouble sleeping goes on for more than a few weeks, talk to a doctor. Lasting sleep problems can have causes that a tea or supplement will not fix.
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Sources
- Adib-Hajbaghery M, Mousavi SN. The effects of chamomile extract on sleep quality among elderly people: A clinical trial. Complement Ther Med. 2017;35:109-114. Opened 2026-10-07.
- Zick SM, Wright BD, Sen A, Arnedt JT. Preliminary examination of the efficacy and safety of a standardized chamomile extract for chronic primary insomnia: a randomized placebo-controlled pilot study. BMC Complement Altern Med. 2011;11:78. Opened 2026-10-07.
- Chang SM, Chen CH. Effects of an intervention with drinking chamomile tea on sleep quality and depression in sleep disturbed postnatal women: a randomized controlled trial. J Adv Nurs. 2016;72(2):306-315. Opened 2026-10-07.
- Mohsenzadeh-Ledari F, Agajani Delavar M, Moghadamnia AA, et al. Efficacy and safety of Matricaria chamomilla intervention in managing menopausal symptoms: a triple-blind clinical trial. Menopause. 2025;32(4):353-358. Opened 2026-10-07.
- Mao JJ, Xie SX, Keefe JR, et al. Long-term chamomile (Matricaria chamomilla L.) treatment for generalized anxiety disorder: A randomized clinical trial. Phytomedicine. 2016;23(14):1735-1742. Opened 2026-10-07.
- National Center for Complementary and Integrative Health. Chamomile. Bethesda (MD): National Institutes of Health. Last updated November 2024. Opened 2026-10-07.
- Kazemi A, Shojaei-Zarghani S, Eskandarzadeh P, Hashempur MH. Effects of chamomile (Matricaria chamomilla L.) on sleep: A systematic review and meta-analysis of clinical trials. Complement Ther Med. 2024;84:103071. Opened 2026-10-07.
This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.