If you are curious whether a probiotic can affect sleep, L. helveticus is one of the few with a sleep study behind it. The study was small, and its results were mixed. Here we look at what L. helveticus is, what that sleep study found, what a stress study found, and how much is in Sleep Harmony.
In this article
From Anirva, the maker of Sleep Harmony. This article is general information, not medical advice. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.
- L. helveticus is a lactic acid bacterium used in fermented milk. It is one of three probiotics in Sleep Harmony. [5]
- A small study tested fermented milk in older adults. Sleep improved from the start of the study, but not significantly more than with placebo. [3][4]
- A stress study used L. helveticus with a second probiotic. Its results describe the two-strain product, not L. helveticus alone. [6]
- Effects depend on the specific strain. Sleep Harmony's label lists the species and CFU count, as most probiotic labels do, not the strain. [1][2]
Facts at a Glance
| Fact | Detail |
|---|---|
| Ingredient | L. helveticus, one of 3 probiotics in Sleep Harmony [5] |
| Amount in Sleep Harmony | 2 billion CFU a day, in 2 capsules [5] |
| Sleep study | Fermented milk, 29 adults aged 60–81, 3 weeks [3] |
| Stress study | R0052 + B. longum R0175, 30 days in adults [6] |
| Last reviewed | [DATE] |
What Is L. Helveticus?
L. helveticus is a lactic acid bacterium. It is used in fermented milk, including the milk drink tested in the sleep study below, and it is sold as a probiotic. [3] Probiotics are live microorganisms intended to have health benefits when consumed. [2]
Sleep Harmony contains 2 billion colony-forming units (CFUs) of L. helveticus in each two-capsule serving. [5] CFUs show how many live microorganisms a product contains. [1]
As we explain in our L. rhamnosus article, effects depend on the specific strain. [1][2] Like most probiotic labels, Sleep Harmony's names the species and CFU count rather than the strain, so we can't confirm whether it's the exact strain studied below — treat the research here as what's known about L. helveticus generally, not a guarantee about this specific product.
The Sleep Study: Fermented Milk in Older Adults
This study, published in 2009, included 29 healthy adults aged 60 to 81. [3] Each person drank 100 grams of L. helveticus fermented milk a day for 3 weeks. They also drank a placebo milk for 3 weeks, with a 3-week break in between. [3]
Sleep was measured with a wrist activity monitor and with questionnaires. [3] After the fermented milk, sleep efficiency and the number of times people woke during the night improved compared with the start. [3]
However, the improvements were not significantly different from the placebo period. [4] The authors concluded that the fermented milk may have a more favorable effect on sleep than placebo, and that this deserves more study. [3]
This study tested fermented milk, not capsules, so its results may not apply to a probiotic capsule.
The Stress Study: A Two-Strain Product
A 2011 paper tested a product with two probiotics: L. helveticus R0052 and Bifidobacterium longum R0175. [6] It included both a rat study and a human study. [6]
In rats, two weeks of the product reduced stress-related behavior. [6] In healthy adults, 30 days of the product lowered self-rated distress scores and a stress hormone, compared with placebo. [6] This study did not measure sleep.
Because the product contained two strains, these results cannot be credited to L. helveticus alone.
Study summary
| Study | Who | Product | Length | Main Result |
|---|---|---|---|---|
| Yamamura et al., 2009 [3][4] | 29 healthy adults, 60–81 | 100 g fermented milk a day | 3 weeks each (crossover) | Sleep improved vs. the start; not significantly different from placebo. |
| Messaoudi et al., 2011 [6] | Rats; healthy adults | L. helveticus R0052 + B. longum R0175 | 2 weeks (rats); 30 days (people) | Lower distress scores vs. placebo; sleep not measured. |
How Much Is in Sleep Harmony?
Sleep Harmony contains 2 billion CFU of L. helveticus per 2-capsule serving. [5] The sleep study used fermented milk, not a CFU-labeled capsule, and the stress study used a two-strain product — so neither gives a directly comparable amount.
| Source | L. helveticus | Notes |
|---|---|---|
| Sleep Harmony (2 capsules) | 2 billion CFU | Strain not specified on the label [5] |
| Sleep study | Fermented milk | CFU not comparable — a food, not a capsule [3] |
| Stress study | Strain R0052 | Combined with a second probiotic [6] |
14 ingredients, including 2 billion CFU of L. helveticus
Sleep Harmony is a nightly two-capsule supplement that pairs L. helveticus with two other probiotic strains, melatonin, valerian, magnesium, L-theanine and more. Every ingredient is listed on the label.
See Sleep HarmonySafety
The risk of harm is greater in people with severe illnesses or weakened immune systems. [2] Some probiotic products have been found to contain microorganisms other than those on the label. [2]
L. Helveticus Is One Part of Sleep Harmony
Sleep Harmony combines melatonin, calming herbs and three probiotics in one formula. We chose ingredients that have each been studied for relaxation and sleep. L. helveticus is one of them.
Sleep Harmony has not been clinically tested as a finished product. For this reason, we cannot say how its ingredients work together. The studies in this article tested fermented milk or a two-strain product.
If you take Sleep Harmony, you are not relying on L. helveticus alone. It is one of 14 ingredients in each serving.
If You Are Deciding
The evidence for L. helveticus and sleep is early. Cleveland Clinic suggests a steady sleep schedule, less caffeine and alcohol, and a cool, dark bedroom. [7]
If you would like to try Sleep Harmony, the directions are two capsules 30 to 60 minutes before bedtime. [5]
The Short Version
L. helveticus is a lactic acid bacterium used in fermented milk. In a small study, older adults slept somewhat better after drinking it, but not significantly better than with placebo. A stress study used it with a second probiotic. Sleep Harmony contains 2 billion CFU, alongside 13 other ingredients.
Frequently Asked Questions
Does L. helveticus help you sleep?
Which probiotic strains have been studied for sleep?
Is fermented milk the same as a probiotic capsule?
Does L. helveticus help with stress?
What are the side effects of probiotics?
References
- NIH Office of Dietary Supplements. Probiotics: fact sheet for consumers. Updated November 17, 2025. https://ods.od.nih.gov/factsheets/Probiotics-Consumer/
- National Center for Complementary and Integrative Health. Probiotics: what you need to know. Last updated August 2019. https://www.nccih.nih.gov/health/probiotics-what-you-need-to-know
- Yamamura S, Morishima H, Kumano-go T, et al. The effect of Lactobacillus helveticus fermented milk on sleep and health perception in elderly subjects. Eur J Clin Nutr. 2009;63(1):100–105. doi:10.1038/sj.ejcn.1602898. PMID: 17851460.
- Yamamura S. Thesis abstract (in Japanese) reporting the same study, including the comparison with placebo. Osaka University Knowledge Archive. https://ir.library.osaka-u.ac.jp/repo/ouka/all/48972/21865_Abstract.pdf
- Anirva. Sleep Harmony with Probiotics: Supplement Facts label and product page. https://anirva.com/products/sleep-harmony (accessed September 30, 2026).
- Messaoudi M, Lalonde R, Violle N, et al. Assessment of psychotropic-like properties of a probiotic formulation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) in rats and human subjects. Br J Nutr. 2011;105(5):755–764. doi:10.1017/S0007114510004319. PMID: 20974015.
- Umeda N (expert). Does magnesium help you sleep better? Cleveland Clinic Health Essentials. September 4, 2026. https://health.clevelandclinic.org/does-magnesium-help-you-sleep/
