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Lactobacillus paracasei, 

L. CASEI 431®

- a well-documented probiotic strain

L CASEI 431 probiotic strain
2 Min read

Studied extensively, Lactobacillus paracasei, L. CASEI 431® (hereafter referred to by use of the trademark L. CASEI 431®) has high acid and bile tolerance,1 and its mucosal wall adherence assists pathogenic inhibition,1 barrier function enhancement,2 and immune interactions.3 L. CASEI 431® has in high-quality clinical trials demonstrated support for healthy in immune function.4, 5, 6, 7

Chr. Hansen L. CASEI 431® 

L. CASEI 431® was initially isolated from the fecal sample of a healthy infant. It is able to survive in the gastrointestinal tract and has been used in food and dietary supplements since 1995.

L. CASEI 431® has been described in around 60 scientific publications, out of which more than 20 are publications of human clinical studies; the documented potential immune function benefits, makes L. CASEI 431® a well-documented probiotic strain.

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Immune health L CASEI 431 probiotic strain

L. CASEI 431® key clinical studies within different health areas

Support for healthy immune response

Intake of L. CASEI 431® has in several clinical studies of adults been associated with an immune response towards vaccine challenge models4, 6, 7. L. CASEI 431® intake has been associated with increased levels of antibodies 4, 6, 7, suggesting promotion of the body’s ability to produce antibodies towards a pathogen.

Respiratory health

L. CASEI 431® intake in adults has been associated with a reduction in; common cold and flu-like symptoms, reported doctors’ visits and use of antibiotics.5

Bowel function

L. CASEI 431® has, in combination with Bifidobacterium, BB-12® (hereafter referred to by use of the trademark BB-12®), been associated with improved stool frequency and consistency in infants.8
Active seniors and support of immune health L CASEI 431 probiotic strain


L. CASEI 431® is safe for human consumption and has been granted QPS (Qualified Presumption of Safety) status by EFSA in Europe.It has been tested in clinical studies at levels of up to at least 50 billion CFU/day (colony forming units), alone and in combination with Bifidobacterium, BB-12® with no adverse events.

L. CASEI 431® is a registered trademark of Chr. Hansen A/S.

The article is provided for informational purposes regarding probiotics and is not meant to suggest that any substance referenced in the article is intended to diagnose, cure, mitigate, treat, or prevent any disease.

Our Chr. Hansen probiotic strains

At Chr. Hansen, our strains are backed by science. All of our probiotic strains are supported by clinical documentation. Learn more about the beneficial effects our strains have on different health areas.


References Open Close

1. Jacobsen CN, et al. Screening of probiotic activities of forty-seven strains of Lactobacillus spp. by in vitro techniques and evaluation of the colonization ability of five selected strains in humans. Appl Environ Microbiol. 1999;65(11):4949-56. (PubMed)
2. Internal Chr. Hansen data on file.
3. Zeuthen LH, et al. Lactic acid bacteria inducing a weak interleukin-12 and tumor necrosis factor alpha response in human dendritic cells inhibit strongly stimulating lactic acid bacteria but act synergistically with gram-negative bacteria. Clin Vaccine Immunol. 2006;13(3):365-75. (PubMed)
4. Rizzardini G, et al. Evaluation of the immune benefits of two probiotic strains Bifidobacterium animalis ssp. lactis, BB-12® and Lactobacillus paracasei ssp. paracasei, L. casei 431® in an influenza vaccination model: a randomised, double-blind, placebo-controlled study. Br J Nutr. 2012;107(6):876-84. (PubMed)
5. Jespersen L, et al. Effect of Lactobacillus paracasei subsp. paracasei, L. casei 431 on immune response to influenza vaccination and upper respiratory tract infections in healthy adult volunteers: a randomized, double-blind, placebo-controlled, parallel-group study. Am J Clin Nutr. 2015;101(6):1188-96. (PubMed)
6. Trachootham, D. et al. Drinking fermented milk containing Lactobacillus paracasei 431 (IMULUSTM) improves immune response against H1N1 and cross-reactive H3N2 viruses after influenza vaccination: A pilot randomized triple-blinded placebo controlled trial. Journal of Functional Foods. 2017;33, 1–10. 
7. De Vrese, M. et al. Probiotic bacteria stimulate virus-specific neutralizing antibodies following a booster polio vaccination. European Journal of Nutrition. 2005;44(7), 406–413. (PubMed)
8. Vlieger AM, et al. Tolerance and safety of Lactobacillus paracasei ssp. paracasei in combination with Bifidobacterium animalis ssp. lactis in a prebiotic-containing infant formula: a randomised controlled trial. Br J Nutr. 2009;102(6):869-75. (PubMed)
9. EFSA Panel on Biological Hazards (BIOHAZ). Statement on the update of the list of QPS-recommended biological agents intentionally added to food or feed as notified to EFSA 3: Suitability of taxonomic units notified to EFSA until September 2015. EFSA Journal. 2015;13:4331. 

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