L. reuteri strains

At BioGaia we focus on different strains of lactic acid bacteria.

The first strain of Lactobacillus reuteri (L. reuteri) for human use, L. reuteri DSM 17938, was isolated in 1990 from the breast milk of a Peruvian mother living in the Andes. The commercial name is L. reuteri Protectis.

Other human strains used commercially are L. reuteri ATCC PTA 5289 and ATCC PTA 6475. L. reuteri ATCC PTA 5289 used in oral health products was isolated from the oral cavity of a Japanese woman with remarkable good dental status and L. reuteri ATCC PTA 6475 was isolated from breast milk in Finland.


BioGaia Probiotics, grounded in evolution, driven by science

Because L. reuteri strains have co-evolved with humans since the beginning of time they are adapted to their host. L. reuteri is among the first bacterial species to become naturally established in the normal microbiota of the new-born.

In humans BioGaia’s L. reuteri species have been isolated from:

  • Breast milk
  • The vagina
  • The mouth
  • The stomach
  • The small intestine
  • The large intestine
  • Faeces

All our commercial strains are of human origin, naturally colonise humans, and are therefore more likely to actually have a positive effect on human health. Even an indigenous bacterium like BioGaia’s L. reuteri Protectis should be taken on a regular basis, to reach high enough levels to achieve proper colonisation and have a good effect.


Strain specificity

Lactic acid bacteria are divided into families, genera, species and strains. An example from a completely different area, cheese, could be used to clarify the system. Different strains of the same bacteria may have different characteristics, just like a Brie de Maux differs from a Camenbert, even though both are white mold cheeses. This is why bacteria must be distinguished and tested in clinical trials at strain level.

When talking about lactic acid bacteria we need to clarify which strain we refer to, because the fact that a product contains “lactic acid bacteria” or “L. reuteri” is not enough. Only by including the strain name, such as L. reuteri DSM 17938, we are specific about exactly which lactic acid bacterium we are referring to.


To date the efficacy and safety of BioGaia’s different strains of L. reuteri have been documented in 163 studies in 14,000 people of all ages. Results have been published in 136 papers in scientific journals (September 2016). This makes it one of the most studied probiotics in the world. BioGaia’s commercial strains of L. reuteri are derived from breast milk and saliva in humans.


Dosage and colonisation 

Based on clinical data 100 million CFU/day has been chosen as a safe and efficacious dose of L. reuteri Protectis in man. Further, since L. reuteri colonisation is transient, dosing should be maintained to ensure adequate and stable L. reuteri levels in the gastrointestinal tract. Colonisation of L. reuteri Protectis has been studied throughout the entire human gastrointestinal tract using biopsies technique.



BioGaia’s L. reuteri is one of the most scientifically well-documented probiotics with regard to both efficacy and safety, tested in 14,000 infants, children and adults.

BioGaia’s L. reuteri has been tested for host tolerance in term and preterm infants, children, healthy adults and immune compromised adults. No serious adverse effects have been observed up to the maximum tested dosage of 10 billion CFU/day, meaning 1000 times the recommended daily dose.


Read more about the Safety studies 


Read more about our Expertise 

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