Chamomile: The Everyday Herb With Real Sleep and Anxiety Research Behind It

Chamomile is the supplement world's oldest cliché — the tea your grandmother made you before bed. That familiarity has a downside: it's easy to write chamomile off as folk medicine with no real research behind it. That's wrong. Chamomile has one of the more substantial human trial records of any calming herb, including a study whose randomised, placebo-controlled phase alone ran for 26 weeks — unusually long for a botanical. Here's what the research actually shows, what dose it was tested at, and how that compares to what's in Sleep Formula.

What chamomile is, and what's doing the work

"Chamomile" usually means German chamomile (Matricaria chamomilla, also called Matricaria recutita), a daisy-like flower that's been used in traditional medicine for centuries. The flower head contains dozens of compounds, but the one researchers keep coming back to is apigenin, a flavonoid concentrated in the plant's essential oil and extracts.

Chamomile is one of seven fully disclosed actives in Sleep Formula, which is the only product in our range where every ingredient's milligram amount is printed on the label — the full breakdown is in Inside Sleep Formula, and how it differs from Sleep Support is in Sleep Formula vs. Sleep Support: how to actually choose.

Apigenin is interesting because it isn't just "antioxidant-rich plant compound number 400." It has a proposed mechanism that's specific and testable: apigenin binds to benzodiazepine receptor sites on the GABA-A receptor complex — the same general receptor system that drugs like diazepam act on, though apigenin's binding affinity and effects are far weaker.² That's a plausible explanation for chamomile's calming, sleep-supportive reputation, and it's why apigenin content (not just "chamomile" as a vague label) is what standardized extracts are measured against.

The anxiety evidence: a real, long-running RCT

Most herbal supplement studies run for a few weeks. Chamomile has something rarer: a long-term randomized controlled trial in people formally diagnosed with generalized anxiety disorder (GAD), not just "stressed adults." Researchers gave 179 participants pharmaceutical-grade chamomile extract (1,500 mg/day, split into three 500 mg doses) for 12 weeks in an open-label phase. Just over half responded well enough to move into a 26-week double-blind, placebo-controlled continuation phase.¹

The relapse rate was numerically lower on chamomile than placebo (15.2% versus 25.5%), but that difference didn't reach statistical significance. The hazard ratio was 0.52, but with a confidence interval running from 0.20 to 1.33 and P = 0.16 — which is to say the trial could not rule out chance. Only 93 of the original 179 participants (51.9%) responded well enough to be randomised at all, split 46 to chamomile and 47 to placebo, so the relapse comparison rests on 19 relapse events in total. That is a small number of events on which to hang a claim either way.

What was statistically significant: participants who stayed on chamomile had a smaller increase in GAD-7 symptom scores over follow-up than those switched to placebo (P = 0.0032), and showed lower body weight (P = 0.046) and lower mean arterial blood pressure (P = 0.0063). The trial's own conclusion was measured — long-term chamomile was safe and reduced GAD symptoms, but was not shown to prevent relapse.¹

Chamomile isn't a substitute for anxiety treatment. It's a mild, well-studied option for people looking for daily support — and one of the few herbs with a trial long enough to actually test that claim.

Passion flower is the other calming botanical with genuinely comparable trial data, and its strongest study tested it against a prescription benzodiazepine rather than a placebo. The two have not been compared head-to-head in a single trial — what exists is separate evidence for each, which we've set side by side in chamomile and passion flower for anxiety: what the trials actually found, with passion flower's oxazepam comparison covered in passion flower for anxiety and sleep.

The sleep evidence

Separate from the anxiety research, chamomile has been tested specifically for sleep quality. In a randomized trial of 60 adults in a daycare nursing home in Karaj, Iran (30 per arm, mean age around 70), 200 mg of chamomile extract twice daily — 400 mg/day — for 28 days significantly improved overall Pittsburgh Sleep Quality Index scores compared with a wheat-flour placebo at both the end of treatment (P = 0.007) and two weeks afterwards (P = 0.002).³ Two honest qualifiers on that: the PSQI sleep duration component did not change significantly, which the authors attributed to the short intervention window, and neither did habitual sleep efficiency. So the improvement was in how well people rated their sleep, not in how long they slept.

A separate trial in postpartum women with disrupted sleep found that drinking chamomile tea for two weeks improved sleep quality and reduced depressive symptom scores relative to usual care.⁴ That one had no placebo arm — the comparator was usual care, so expectancy effects are not controlled — and the follow-up was short. Neither trial is enormous, and both are single-centre. The direction is consistent across different populations and different chamomile formats (capsule extract vs. tea), which is worth something; it is not the same as replication by an independent group.

Studied doses vs. what's in Sleep Formula

One of the more confusing things about herbal supplements is that "chamomile" on a label can mean wildly different amounts of actual extract. Here's how the doses used in research compare:

The 100 mg dose in Sleep Formula is lower than what was used in the standalone GAD and elderly-sleep trials — it's included as one contributor within a formula, not a stand-alone chamomile intervention at the studied dose. That's a distinction worth being upfront about: chamomile's own research supports doses four to fifteen times higher than 100 mg, and a formula's job is balancing multiple ingredients rather than maxing out any single one. Nobody has run a trial on Sleep Formula itself, so the ingredient evidence above is not evidence for the product.

For context on where a mild botanical sits relative to everything else you could do about anxiety, the ranked version of that evidence is in what actually works for anxiety: the evidence, in order. Chamomile is not near the top of that list, and we'd rather say so here than let a 26-week trial imply otherwise.

Safety: well-tolerated, with two real cautions

Chamomile has a long track record and is generally very well tolerated — most trials, including the 26-week one above, report mild or no side effects.⁵ Two things are worth knowing regardless:

• Ragweed and related-plant allergies. Chamomile belongs to the Asteraceae (daisy) family, along with ragweed, chrysanthemums, marigolds, and daisies. People with allergies to those plants have a meaningfully higher risk of allergic reaction to chamomile, including rare but serious hypersensitivity reactions.⁵
• Blood thinners. This is the same general caution that applies to fish oil, and for anyone on an anticoagulant it's worth reading alongside does fish oil interact with blood thinners? Chamomile has been reported to interact with warfarin, including a documented case report of elevated bleeding risk (INR) in a long-term chamomile tea user also on warfarin.⁶ Anyone on anticoagulant medication should talk to a doctor before adding chamomile in any form.

Bottom line

Chamomile earns more credit than "just tea" gives it. The apigenin mechanism is specific and testable, the anxiety trial is one of the longest of its kind for any herbal option, and the sleep data — while smaller — points the same direction across different populations. Hold two things in mind, though: that long trial did not show chamomile preventing relapse (15.2% vs 25.5%, P = 0.16), and the sleep trials are small, single-centre and in one case placebo-free. If you're chamomile-curious, know that the doses shown to move the needle in trials are higher than what most single-serving teas or low-dose blends provide, and check with your doctor first if you're on a blood thinner or have ragweed-family allergies.

This article is for informational purposes only and has not been evaluated by the FDA. It is not intended to diagnose, treat, cure, or prevent any disease. Speak with a healthcare provider before starting any new supplement, especially if you take medication or have an existing health condition.

References

1. 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. PubMed 27912875.
2. Avallone R, Zanoli P, Puia G, et al. Pharmacological profile of apigenin, a flavonoid isolated from Matricaria chamomilla. Biochem Pharmacol. 2000;59(11):1387-1394. PubMed 10751547.
3. 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. PubMed 29154054.
4. 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. PubMed 26483209.
5. National Center for Complementary and Integrative Health (NCCIH), NIH. Chamomile: Usefulness and Safety. nccih.nih.gov/health/chamomile.
6. Segal R, Pilote L. Warfarin interaction with Matricaria chamomilla. CMAJ. 2006;174(9):1281-1282. PubMed 16636327.
7. Keefe JR, Guo W, Li QS, Amsterdam JD, Mao JJ. Short-term open-label chamomile (Matricaria chamomilla L.) therapy of moderate to severe generalized anxiety disorder. J Psychiatr Res. 2016;84:26-32. PubMed 27912871.

Related reading: Inside Sleep Formula: what's in it and why · Lemon balm: what the research says about calm and sleep

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