Lactobacillus reuteri Benefits: What It Does in the Gut

You may not have heard of Lactobacillus reuteri, but there's a fair chance you already carry some of it. In fact, it's one of the few probiotic bacteria that lives naturally in the human gut. In adults, it's best studied for two things: keeping bowel movements regular and easing the side effects of treatment for Helicobacter pylori, which is a common stomach infection (Guarner et al.; Francavilla et al.).

What is Lactobacillus reuteri?

Limosilactobacillus reuteri, still commonly sold as Lactobacillus reuteri, is a lactic acid bacterium found naturally in the gut, although the amount people carry varies widely (Mu et al.). It got its new name in 2020, when 23 new genera were split off from Lactobacillus (Guarner et al.). Many labels haven't caught up yet, which is why you'll see both names.

In the gut, L. reuteri produces reuterin and organic acids. These compounds make it harder for disease causing microbes to settle in (Mu et al.).

What does the evidence show about Lactobacillus reuteri benefits?

Nearly all the adult evidence comes from one strain, L. reuteri DSM 17938, sometimes paired with a second strain, ATCC PTA 6475. It also comes from a fairly small number of trials (Guarner et al.).

Constipation. The World Gastroenterology Organisation's 2023 global guideline on probiotics looks at the trials behind each strain (Guarner et al.). For adults with functional constipation, meaning ongoing constipation with no medical cause, it rates DSM 17938 as supported by more than one randomised trial with consistent results. The benefit is more frequent bowel movements and fewer constipation symptoms (Guarner et al.).

H. pylori treatment. Clearing H. pylori means a course of antibiotics, which often brings diarrhoea and nausea along with it. International guidance concludes that certain probiotics can reduce these side effects, though the quality of that evidence is weak (Guarner et al.). A 2026 meta analysis of L. reuteri found fewer cases of diarrhoea and nausea during treatment, while cure rates stayed the same (Francavilla et al.).

Irritable bowel syndrome. There's a hint of benefit here. In a 14 week trial of 140 adults, two L. reuteri strains improved IBS symptom scores compared with placebo (Cruchet et al.). One trial isn't enough to go on, though.

How to choose an L. reuteri probiotic supplement

Since the benefits are tied to specific strains, start with the label. A good one names the strain, not just the species, and tells you how many live bacteria are left at the end of the shelf life, not just at manufacture (Guarner et al.).

If you're pregnant, immunocompromised or on regular medication, check with a doctor or pharmacist before you start.

L. reuteri in AMILI's Digestive Health Daily Synbiotics

AMILI's Digestive Health Daily Synbiotics is made for people with bloating, irregular bowel habits or sensitive digestion. It combines L. reuteri with Lactiplantibacillus plantarum, Bifidobacterium breve and Lacticaseibacillus rhamnosus. The strains were chosen using AMILI's unique database of multiethnic Asian gut microbiomes.

If you're looking for where to buy Lactobacillus reuteri in Singapore, the Digestive Health Daily Synbiotics is available at amili.asia. To see whether it suits your gut, take the AMILI Gut Health Test first, which recommends a formulation based on your results.

Glossary

• Strain: a genetic variant within a species, identified by a code such as DSM 17938.
• Reuterin: a compound made by L. reuteri that stops other microbes from growing.
• Meta-analysis: a study that pools the results of several trials.