Ingredient deep-dive

Chamomile And Sleep: Who Was Actually In The Trials?

Search for chamomile and sleep and you get a confident answer in about four seconds. The research gives a less tidy one, and most of the untidiness comes down to who was sitting in the trial: adults with diagnosed insomnia, retirees in care homes, new mothers, people with clinical anxiety. A herb can look useful in one of those rooms and unremarkable in another. This article reads the chamomile studies by who was in them.

By Serenity Prime Team · Last updated September 26, 2026 · 13 min read · Ingredient deep-dive

Why chamomile gets its own article

Chamomile is the herb people mean when they say “herbal sleep aid.” It is the tea in the cupboard, and the Michigan team behind one of the trials below opens its paper by calling it the most commonly used herbal for sleep disorders. That familiarity is exactly why it deserves a slower look: when everybody already believes something, nobody checks which study it came from.

This site has already said where chamomile sits. The ingredients page sorts all thirteen names by how much human research stands behind each, and puts chamomile in the middle: two sleep trials that disagree with each other, and a larger anxiety trial that used a much bigger dose. That is a fair summary and a short one. What it leaves out is the interesting part, which is that the disagreement isn’t random. The trials disagree because they asked different questions of different people, gave different preparations for different lengths of time, and compared against different things.

So this is a tour of the rooms. Four kinds of participant, several kinds of design, and one plant.

What the Serenity Prime label says about it, which is very little

The seller lists chamomile as Matricaria chamomilla, sixth on the written list of thirteen and one of the six the vendor chose to draw. That is everything the seller says. The bottle face carries the brand, the words DIETARY SUPPLEMENT and the figure 60 CAPSULES, and this website’s label page records that no Supplement Facts panel appears in the vendor’s image pack or on the seller’s page. The back of the bottle has never been photographed.

Which means two things a reader should keep in view for the rest of this article. First, nobody outside the factory can say how many milligrams of chamomile a capsule holds, or whether the amounts are printed one by one or grouped under a single blend weight. That is a question for the back label of the bottle you receive. Second, the plant part is unstated. The published abstracts below don’t all say which part of the plant went into the extract, and an ingredient made from a different part would be a different material. Every milligram figure here belongs to a published study, not to this capsule.

Adults with diagnosed insomnia: 34 people, 28 days

If the question is “does chamomile help someone whose insomnia has been diagnosed,” the trial that comes closest is Zick and colleagues’ 2011 pilot from the University of Michigan. It enrolled 34 adults aged 18 to 65 who met the DSM-IV definition of primary insomnia and had had it for at least six months. Participants were randomised to 270 mg of a standardised chamomile extract twice a day or to placebo, and it ran for 28 days. The primary outcomes were sleep diary measures: total sleep time, sleep efficiency, time to fall asleep, time awake after falling asleep, sleep quality and the number of awakenings.

The result is the one nobody puts on a label. There were no significant differences between the groups on any of the diary measures. The authors report small-to-moderate effect sizes, with time to fall asleep, night-time awakenings and a daytime fatigue scale leaning towards chamomile. Total sleep time, though, showed a moderate effect in favour of placebo. Daytime functioning looked a little better on chamomile, but not by a margin that reached significance. There was no difference in adverse events.

The National Center for Complementary and Integrative Health reads the literature the same way. Its chamomile fact sheet says there is very little information on chamomile and insomnia, and that a 2019 review found one study on insomnia, which found no benefit.

Older adults in care settings: two trials, one placebo

Two of the more positive sleep results come from older adults living in institutional settings in Iran, and they are worth reading side by side because their designs differ in ways that matter.

Adib-Hajbaghery and Mousavi (2017) randomised 60 people aged 60 or over at a day-care nursing home in Karaj. The treatment group took 200 mg chamomile extract capsules twice a day for 28 days; the control group took 200 mg wheat-flour capsules on the same schedule. Sleep was scored on the Pittsburgh Sleep Quality Index before the start, two weeks in, at the end, and two weeks after stopping. Both groups began with poor sleep quality and no difference between them. After the intervention, the chamomile group’s sleep quality was significantly better than the control group’s (P < 0.05). It was described as single-blind, which means one party, rather than both, was kept unaware of who received which capsules.

Abdullahzadeh and colleagues (2017) studied 77 older adults in nursing homes in Isfahan. The intervention group took 400 mg capsules of chamomile twice a day, after lunch and after dinner, for four weeks. The control group received nothing. The authors call the design quasi-experimental. Sleep quality on the same questionnaire differed significantly between the groups afterwards (P < 0.001).

Set those two next to each other. The daily amounts, by simple arithmetic, were 400 mg in the first and 800 mg in the second: a twofold difference, and both reported a benefit on the same questionnaire. One had a placebo and one had no comparison capsule at all. When a result appears across doses that far apart, it is either a wide, forgiving effect or it is mostly measuring something other than the dose, such as expectation, attention from staff, or a questionnaire that people fill in more kindly after being given something. The trials can’t tell those apart, and neither can this desk.

New mothers drinking tea for two weeks

The third positive result changes both the population and the preparation. Chang and Chen (2016) recruited 80 Taiwanese women who had recently given birth and who scored 16 or more on a postpartum sleep-quality scale, the cut-off the paper uses to define poor sleep quality. Forty were assigned to drink chamomile tea for two weeks and forty received regular postpartum care only. The assignment was systematic with a random start rather than fully randomised.

The tea group scored significantly lower on physical-symptoms-related sleep inefficiency (P = 0.015) and on depressive symptoms (P = 0.020). Then the paper adds the sentence that matters most for a shopper: at the four-week follow-up the scores on all three instruments were similar in both groups, so the authors conclude the positive effects were limited to the immediate term.

This is a good example of how a single population can tell you something a headline can’t. A newborn’s parent is sleep-deprived for reasons no herb touches. The finding may reflect a warm evening drink and a deliberate wind-down as much as anything in the plant, and the control group did not get a comparison drink. That does not make the result worthless; it makes it a result about a tea ritual in new mothers, and a fading one.

The anxiety trials, kept at arm’s length

Chamomile’s biggest trials aren’t about sleep, and they get quoted in sleep marketing anyway, so it’s worth being exact about what they did.

Amsterdam and colleagues (2009) randomised 57 outpatients with mild-to-moderate generalised anxiety disorder to a chamomile extract or placebo for eight weeks. The drop in total Hamilton Anxiety score was greater on chamomile (P = 0.047), which is a statistically significant result sitting very close to the line. The authors describe it as suggesting “modest anxiolytic activity.” One patient in each group dropped out over an adverse event.

Seven years later, Mao and colleagues (2016) tested long-term use in people with moderate-to-severe generalised anxiety. In the first phase, 179 people took 1,500 mg of chamomile extract a day (500 mg three times daily) in the open, for 12 weeks. The 93 who responded were then randomised to 26 more weeks of chamomile or placebo. Relapse was 15.2% (7 of 46) on chamomile and 25.5% (12 of 47) on placebo, which sounds meaningful and did not reach statistical significance (hazard ratio 0.52, 95% confidence interval 0.20 to 1.33, P = 0.16). Anxiety symptoms during follow-up were significantly lower in the chamomile group (P = 0.0032).

Two cautions. These are anxiety disorders, not insomnia, and neither trial reports sleep as its target. And the doses in the second are almost three times the 540 mg a day used in the insomnia pilot, which is the number to remember whenever an anxiety result is used to argue for a sleep product.

Two meta-analyses, side by side

Pooling trials sounds like a way of getting rid of the noise. Sometimes it just gives the noise a number.

Hieu and colleagues (2019) included 12 randomised trials. For sleep quality they report a significant improvement after chamomile (standardised mean difference −0.73, 95% confidence interval −1.23 to −0.23). For insomnia proper, only one trial existed and it found no significant change in the Insomnia Severity Index. For generalised anxiety, the Hamilton scale improved at two and four weeks. For anxiety pooled across three trials there was no difference. The authors say larger trials are needed.

Kazemi and colleagues (2024) searched up to August 2023 and included ten studies with 772 participants. They pooled five for the Pittsburgh Sleep Quality Index and found a significant reduction (weighted mean difference −1.88, 95% confidence interval −3.46 to −0.31), with an I² of 88.4%. That figure means most of the variation between the studies was real disagreement rather than chance, which is a warning that the average hides very different trials. Beyond that, the picture is split: time to fall asleep or ease of getting to sleep improved in three of four studies; awakenings improved in two of three; sleep efficiency did not change in two studies and deteriorated in one; daytime functioning did not change in any of the three that measured it; and the authors note that only one study surveyed how well blinding worked and tested the purity or potency of the product used.

All the trials in one table

The design differences are easier to see laid out flat. Every row is a published study; none is a statement about this capsule.

GAD is generalised anxiety disorder. The first four rows have a sleep outcome; the last two are anxiety trials shown for the dose comparison.

What the National Institutes of Health say about safety

For safety, the most useful single document is the National Center for Complementary and Integrative Health’s chamomile fact sheet. It describes chamomile as likely safe in the amounts found in teas and other foods, and possibly safe for medicinal use by adults over the short term. It lists nausea, dizziness and allergic reactions, including severe hypersensitivity reactions and anaphylaxis, as possible in some people, and says people are more likely to react if they are allergic to related plants such as ragweed, chrysanthemums, marigolds or daisies.

Three further points belong on a page like this. The fact sheet says chamomile might have some of the same effects as estrogen, that preliminary studies suggest taking it with birth control pills might reduce their effect, and that it might worsen conditions sensitive to estrogen exposure. It says interactions with some drugs metabolised by the liver and with warfarin have been reported, with theoretical reasons to suspect interaction with other drugs such as sedatives. And it says little is known about safety in pregnancy or while breastfeeding. Anybody taking a prescription medicine should raise a chamomile-containing product with their prescriber first, which is the same advice this site gives about the St. John’s wort on the same list.

Four questions to ask of any chamomile claim

1. Who was in the study? A benefit in retirees, in new mothers or in people with anxiety is not a benefit in you unless you resemble them. The one diagnosed-insomnia trial did not find one.
2. What was the comparison? Placebo capsules, nothing at all and “usual care” answer three different questions. The last two can’t separate the herb from the attention.
3. What was measured, and by whom? Most positive results here are questionnaire scores. The one trial that used sleep diaries in diagnosed insomnia found no significant difference, and the 2024 reviewers say objective measures are still needed.
4. Did it last? The tea trial’s effect was gone by week four. A short window that closes is a different product from a lasting one, and how long a sleep supplement takes to judge sets out how to tell for yourself over a real trial period.

What this evidence does and does not support

Read fairly, the chamomile literature supports three modest statements. Chamomile has been given to a range of people in a range of forms without a signal of serious harm in the trials above, though the 2024 review notes that adverse events were mostly watched for passively. Questionnaire-measured sleep quality was better in several small studies and in two pooled analyses. And the signal was strongest in the least tightly controlled designs and weakest in the one trial of diagnosed insomnia.

It does not support a claim that chamomile treats insomnia, that any particular dose works, or that a capsule of unknown amount does what a tea of known preparation did in a two-week study. It also can’t say anything about this capsule, because the seller has not published what it contains. If chamomile is the reason you are considering a formula, the honest way to use this article is to ask the order desk on +1 (302) 200-3480 to read you the back label, check that a chamomile amount is printed, and then compare it against the 400 to 800 mg a day the sleep capsule trials used, knowing that even then it is a comparison of numbers and not of outcomes.

If you want the strongest single ingredient in the formula by this site’s own reckoning, that is ashwagandha, read one trial at a time. For the ingredients that are recognisably calming herbs, the passionflower and lemon balm and skullcap articles do for those names what this one does for chamomile.

References