The Quick Answer
Valerian has the most research, but its results are mixed. Chamomile, passionflower and ashwagandha have smaller, more encouraging trials. No herb here has strong proof of treating insomnia, and the extract type and amount used matter a great deal.
In this article
When you are looking for a gentler way to wind down, herbs are a natural place to start, and people have turned to them for sleep for a very long time. Several herbs that help you sleep have been studied, and some results are encouraging, though none has strong proof yet. Valerian is the best studied, with mixed results. Chamomile, passionflower, lemon balm, hops and ashwagandha have smaller trials.
Key takeaways
- Valerian is the best studied. Results across many trials are mixed.
- Some encouraging results. Chamomile improved sleep quality in a 2019 review, passionflower added about 23 minutes of sleep in one trial, and ashwagandha had a small effect across five trials.
- Lemon balm and hops have less research on their own. Hops is mostly tested alongside valerian.
- Extract and amount matter. Studies often used more than many supplements contain, so results may not carry over.
- These herbs are one part of Sleep Harmony. You are not relying on any single herb.
How much research is there on sleep herbs?
Herbs are a little harder to study than single chemicals, because two products with the same herb name can differ in the plant part, the extract and the strength. Trials are also often small and short. A 2025 review of over-the-counter insomnia products listed valerian, lemon balm with fennel, and valerian with hops and passionflower as promising, and it reported mostly mild side effects and no serious ones.
A 2020 review noted that valerian with hops is the most studied herb combination, and that data on passionflower and lemon balm were not yet enough to judge them. In the trials below, the gains were often modest, such as a few extra minutes of sleep or a slightly better sleep score.
The herbs, one by one
Valerian
Valerian is the best studied herb, and the results are mixed. A 2006 review of 16 trials covering 1,093 people found that more people said their sleep improved on valerian, although the authors noted publication bias and weak methods. A 2020 review of 60 studies found inconsistent results and suggested that extract quality may explain why. A 2024 umbrella review of eight reviews found no benefit on objective measures of insomnia. The American Academy of Sleep Medicine suggests that doctors not use valerian for chronic insomnia, which is a weak recommendation.
In one small crossover study of eight people, 450 mg cut the time to fall asleep from about 16 to 9 minutes, and 900 mg did not. Valerian trials often used 400 to 600 mg of extract.
Chamomile
A 2019 review of 12 trials found better sleep quality with chamomile. The one trial in people with insomnia found no change in an insomnia score. In a trial of 60 older adults, 200 mg of extract twice a day for 28 days improved sleep quality scores.
Passionflower
Ngan and Conduit tested passionflower tea for one week in 41 healthy adults. Sleep-quality ratings were about 5% better than with parsley tea. Sleep-lab recordings, done in 10 of them, showed no change. In a 2020 trial of 110 adults with insomnia, two weeks of passionflower extract raised total sleep time by about 23 minutes, while placebo showed no change. The other measures did not differ from placebo.
Lemon balm
Lemon balm has small trials so far. In a review of lemon balm studies, 1,500 mg a day for a week improved sleep quality scores after heart surgery. Another review noted better sleep in postmenopausal women taking lemon balm with valerian, and it said more rigorous trials are needed.
Hops
Hops on its own has little human research. A summary of clinical data reports that 100 mg of a hops preparation did not beat placebo in 101 people with chronic insomnia. Hops is usually tested with valerian. In a trial of 184 adults with mild insomnia, a valerian-hops combination had a modest effect, though because valerian was in the mix, the trial cannot show what hops added.
Ashwagandha
A 2021 review of five trials covering 400 people found a small effect of ashwagandha on sleep. The effect was bigger in adults with insomnia, at 600 mg a day or more, and after eight weeks or longer. No serious side effects were reported, and the review noted that safety data are limited.
Why herb results vary
NIH notes that the makeup of valerian products can differ a lot from lot to lot. Some studies used teas, some used dried herb, and some used extracts, in very different amounts. When a study's product is not the one you are holding, its result may not apply.
These herbs are one part of Sleep Harmony
Sleep Harmony contains valerian, lemon balm, hops, chamomile, passionflower and ashwagandha, alongside melatonin, magnesium, L-theanine, GABA, 5-HTP and three probiotics. Sleep Harmony combines melatonin, calming herbs and three probiotics in one formula, and we chose ingredients that have each been studied for relaxation and sleep. So if you are taking Sleep Harmony, you are not relying on any single herb.
The trials above tested each herb on its own, most often at higher amounts. The finished formula has not been clinically tested, so we cannot say how the ingredients work together.
A quick look at the research
| Herb | Research | What it found | Amount used | How solid | Worth knowing |
|---|---|---|---|---|---|
| Valerian | Reviews of 16 to 60 trials | Mixed. Some subjective benefit, none on objective measures in 2024 | 400 to 600 mg extract | Limited | Extract quality varies; publication bias |
| Chamomile | Review of 12 trials | Better sleep quality; no change in one insomnia trial | About 400 mg a day (one trial); tea | Limited | Few trials |
| Passionflower | Two placebo trials (41 and 110 adults) | Better rated sleep; about 23 more minutes in insomnia trial | Tea, 2 g; extract | Limited | Short trials |
| Lemon balm | Small trials | Better sleep scores after surgery and in menopause | 1,500 mg a day; often with valerian | Insufficient | Small, mixed groups |
| Hops | One trial alone; combination trials | No effect alone; modest effect with valerian | 100 mg alone | Insufficient | Rarely tested alone |
| Ashwagandha | Review of 5 trials (400 people) | Small effect on sleep | 600 mg or more a day, 8 weeks or more | Moderate | Small trials; limited safety data |
Good to know
In the 2025 review of over-the-counter insomnia products, side effects were mostly mild and no serious ones were reported. Headache, dizziness and stomach upset are the effects mentioned most often with valerian, and placebo groups reported them too. Valerian may add to the effects of alcohol, some prescription medicines and other supplements such as melatonin, and rare liver problems have been reported with ashwagandha. If you are pregnant, nursing, take prescription medicines or have a health condition, it is a good idea to check with your healthcare provider first.
If you would like to try an herb
Most trials lasted one to eight weeks, so a few weeks gives a fair picture of how a product suits you. Labels that list the extract type and the amount make it easier to compare a product with the studies. And if sleep trouble has been going on for a while, a clinician can help you look at the whole picture.
Explore the formula
About Sleep Harmony
Each 2-capsule serving of Sleep Harmony lists valerian (100 mg), lemon balm (100 mg), hops (100 mg), chamomile (50 mg), passionflower (50 mg) and ashwagandha (125 mg) extracts. For most of these herbs, the studies above used higher amounts, so their results may not apply. Sleep Harmony has not been clinically tested as a finished formula.
See the Sleep Harmony product page →The short version
Herbs are a gentle, well-loved place to start, and the research is still growing. Valerian is the best studied, with mixed results, and ashwagandha has the most consistent small effect. Effects in studies were modest, and the extract and amount used make a difference.
Frequently asked questions
What herbs help you sleep?
Valerian, chamomile, passionflower, lemon balm, hops and ashwagandha have all been studied for sleep. None has strong proof yet, but some trials found encouraging gains, such as slightly better sleep-quality scores or a few extra minutes of sleep. Others found no difference from placebo. The extract type and the amount used strongly affect the results.
Which herb is best for sleep?
No herb is clearly best. Valerian is the most studied, though its results are mixed. Ashwagandha had the most consistent small effect in a 2021 review of five trials, mainly at 600 mg a day or more for at least eight weeks. Chamomile and passionflower have smaller trials, so the evidence does not point to a single winner.
How long do sleep herbs take to work?
Most trials ran from one to eight weeks. In one small valerian study, 450 mg shortened the time to fall asleep. The ashwagandha review found stronger effects at eight weeks or longer. Herbs are not instant, and one night may not tell you much about whether a product suits you.
Are herbs for sleep safe?
Short trials mostly reported mild effects, such as headache, dizziness and stomach upset. Valerian may add to the effects of alcohol, some prescription medicines and other sleep supplements, and rare liver problems have been reported with ashwagandha. Long-term safety data are limited for valerian and ashwagandha.
Can you take sleep herbs with melatonin?
NIH lists melatonin among supplements that might add to valerian's effects, which can mean extra drowsiness. Some blends contain both, and studies of specific combinations are limited. If you use both, it helps to notice how you feel the next morning before you drive.
Does Sleep Harmony work like a single herb?
Sleep Harmony combines melatonin, calming herbs and three probiotics in one formula, so no single herb carries it. The studies here tested each herb on its own, and the finished formula has not been clinically tested, so we cannot say how the ingredients work together.
References
- Over-the-counter products for insomnia in adults: a scoping review of randomised controlled trials. Sleep Med. 2025 [journal and year to be confirmed]. Link
- Guadagna S, et al. Plant extracts for sleep disturbances: a systematic review. Evid Based Complement Alternat Med. 2020. DOI 10.1155/2020/3792390. Link
- Bent S, Padula A, Moore D, Patterson M, Mehling W. Valerian for sleep: a systematic review and meta-analysis. Am J Med. 2006;119(12):1005–1012. PMID 17145239; PMCID PMC4394901. Link
- Merck Manual Professional Version. Valerian. Reviewed July 2025 (summarizes the 2020 Shinjyo meta-analysis and a 2024 umbrella review). Link
- Sateia MJ, Buysse DJ, Krystal AD, Neubauer DN, Heald JL. Clinical practice guideline for the pharmacologic treatment of chronic insomnia in adults. J Clin Sleep Med. 2017;13(2):307–349. PMID 27998379; DOI 10.5664/jcsm.6470. Link
- NIH Office of Dietary Supplements. Valerian: fact sheet for health professionals. (Content dated 2013.) Link
- Hieu TH, Dibas M, Surya Dila KA, et al. Therapeutic efficacy and safety of chamomile for state anxiety, generalized anxiety disorder, insomnia, and sleep quality: a systematic review and meta-analysis. Phytother Res. 2019. PMID 31006899. Link
- NutraIngredients. Chamomile extract may improve sleep among the elderly: RCT. December 11, 2017. Link
- NutraIngredients. Passion flower may boost sleep quality: study. February 17, 2011 (news report of Ngan A, Conduit R. Phytother Res. 2011;25:1153–1159). Link
- Lee J, Jung HY, Lee SI, Choi JH, Kim SG. Effects of Passiflora incarnata Linnaeus on polysomnographic sleep parameters in subjects with insomnia disorder. Int Clin Psychopharmacol. 2020;35(1):29–35. PMID 31714321; DOI 10.1097/YIC.0000000000000291. Link
- Review of Melissa officinalis (lemon balm) extracts, efficacy tables. Curr Neuropharmacol. 2021;19(9):1442–1467 [title to be confirmed]. DOI 10.2174/1570159X19666210726150432. Link
- Review of Melissa officinalis in cognition and sleep quality (UNESP repository) [title, journal and year to be confirmed]. Link
- Drugs.com. Hops (Humulus lupulus): clinical overview. Reviewed November 20, 2025. Link
- LiverTox. Hops (includes summary of Morin CM et al. Sleep 2005;28:1465–1471). NCBI Bookshelf. NBK548872. Link
- 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. PMID 34559859; DOI 10.1371/journal.pone.0257843. Link
- LiverTox. Ashwagandha. NCBI Bookshelf. NBK548536. Link
Author: [Author name to be added]. Reviewed by: none (no reviewer named). Last reviewed: [date to be added at publication].
