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Lactobacillus reuteri is one of the most studied strains of probiotic bacteria, boasting a variety of proven health benefits. From improving your looks to increasing Vitamin D, L. reuteri is worth checking out.

Introduction to Lactobacillus reuteri

L. reuteri is a strain of lactic acid bacteria that live in the intestines, and occasionally the stomachs, of humans (although not all individuals), other mammals, and birds.

Its name comes from German microbiologist, Gerhard Reuter, who discovered it in samples of human intestine and feces in the 1960s.

Different strains of L. reuteri have been shown to have different physiological effects. For example, L. reuteri DSMZ 17648, trademarked “Pylopass” is used for H. pylori (R), while L. reuteri NCIMB 30242, trademarked “Cardioviva” is used to address high cholesterol (R).

In the 1960s, 30-40 percent of the population had L. reuteri as a part of their microbiome. Today it is found in only 10-20 percent (R, R2).

L. reuteri Snapshot


  • Promotes beautiful skin and thick, lustrous hair.
  • Helps fight infections.
  • Is anti-inflammatory and increases beneficial TREGs.
  • Improves gut health – decreasing IBS and IBD symptoms.
  • Lowers cholesterol.


  • May not be good for those with histamine intolerance.
  • May cause weight gain in some people.

Benefits of L. reuteri

1) L. reuteri Promotes Sex Appeal

Animal research on an L. reuteri strain called ATCC PTA 6475 has shown potential for improving skin quality (thickness and “glow”) and creating thick, lustrous hair (R).

The probiotic improved skin and hair quality in both sexes, but in females caused a dramatic improvement in the level of shine of their hair. The L. reuteri caused females to have a more acidic pH, which was found to correlate with hair luster (R).

Therefore, L. reuteri bacteria may restore women’s skin and hair to youthful splendor (R).

When translated into human terms, an acidic pH in the vagina correlates with the time of peak fertility, estimated to be around age 25 (R).

L. reuteri was also shown to improve levels of the “feel good” hormone oxytocin (needs IL-10), which is important for bonding (R).

L. reuteri increases testosterone (needs IL-10(R).

L. reuteri‘s ability to increase testosterone and lower inflammation can potentially benefit implications for male pattern baldness. High IL-17 inflammation can inhibit hair growth, and L. reuteri has been shown to suppress IL-17 (R).

L. reuteri‘s additional perk of strengthening sex drive makes the probiotic an attractive supplement for men (R).

2) L. reuteri is Anti-Inflammatory

L. reuteri has been shown to increase Treg cells in the body, causing an increase in the cytokine IL-10. As a result, Th17 (and its production of IL-17) is suppressed (R, R2).

L. reuteri inhibits NF-κB, one of the most important factors in reducing whole-body inflammation (R). To learn more about NF-kB, read my post, How To Inhibit NF-kB: The Key To Health And Master Control of Inflammation.

Note: L. reuteri may not be good for histamine intolerance.

L. reuteri is able to convert dietary l-histidine into histamine, increasing IL-10, and suppressing TNF-α (by activating the histamine H2 receptor) (R, R2).

3) L. reuteri Lowers Stress and Pain Perception

In animal models of gut pain, L. reuteri has been shown to lower the activation of the nervous system and lessen pain (RR2).

L. reuteri ingestion impacts the nerves in such a way that it may slow gut motility (improving cases of diarrhea) and decrease pain perception (R).

4) L. reuteri Increases Vitamin D

Taking L. reuteri increased blood levels of vitamin D3 by 25.5% in a Canadian study (R).

According to the authors of the study, this is the first time blood levels of vitamin D3 have been increased by oral probiotic supplementation (R).

5) L. reuteri Helps Gut Health

Our gut bacteria need to consume tryptophan in order to make serotonin, which is crucial for proper gut function (R).

When our gut bacteria consume sugar instead of tryptophan, we are more susceptible to Candida and other infections (by not producing AhR ligands) (R).

L. reuteri switches our bacteria’s primary food source from sugar to tryptophan, which helps produce serotonin, and protects our gut from infections.  This lessens susceptibility to gut problems and IBS (R).

L. reuteri helps constipation, increasing the number of bowel movements people have. People went from having 3.89 bowel movements per week to 5.28 (R).

Infants also increased bowel frequency even at a dosage of 100 million cfu (colony forming units) (R).

L. reuteri also decreases the incidence of diarrhea in children (R). 

It inhibited the onset of colitis in mice (R) and may reduce stress-induced colitis flare-ups (R).

Yogurt containing L. reuteri RC-14 and L. rhamnosus GR-1 increased T regulatory cells in patients with Inflammatory Bowel Disease and decreased inflammation (TNF-alpha and IL-12) (R).

A rectal enema of L. reuteri reduced gut lining inflammation in children with active Ulcerative Colitis (R).

6) L. reuteri Fights Candida

L. reuteri RC-14 alone and together with L. rhamnosus GR-1 can inhibit the growth of candida in the vagina (R, R2).

Oral L. reuteri supplementation was effective as nystatin in a study preterm infants and more effective at reducing the incidence of sepsis (R, R2).

Of the 8 probiotic strains tested in the lab, L. reuteri ATCC 55730 showed the strongest inhibition of oral Candida albicans (R).

7) L. reuteri is Good for the Thyroid

In mice, L. reuteri increased thyroid size and activity (increasing T4 levels), lessening the fatigue and weight gain associated with aging and causing a more youthful physical appearance (R).

Crucial to these anti-aging effects is L. reuteri‘s ability to increase anti-inflammatory T regulatory cells (R).

8) L. reuteri Lowers Cholesterol

In one study, L. reuteri reduced LDL cholesterol by 11.64%, reduced total cholesterol by 9.14%, non-HDL-cholesterol by 11.30% and apoB-100 by 8.41% (R).

Hs-C-reactive protein and fibrinogen were reduced by 1.05 mg/l and 14.25%, respectively (R).

Another study used microencapsulated L. reuteri NCIMB 30242 yogurt taken twice a day over 6 weeks by adults with high cholesterol. Results included a reduction of LDL by 8.92% and total cholesterol 4.81% over the course of the study (R).

The L. reuteri in that form and delivery method was found to work better than probiotics traditionally used and comparable to other cholesterol-lowering methods (R).

L. reuteri lowers cholesterol, in part, by reducing the absorption of bile (by increasing the deconjugation of bile in the intestines) (R).

9) L. reuteri Speeds Wound Healing

Supplementing the rat microbiome with L. reuteri in drinking water cuts wound-healing time in half compared to control animals (R).

Lactobacillus reuteri enhances healing by increasing oxytocin via the vagus nerve. The oxytocin then activates Tregs (CD4+Foxp3+CD25+), which improves the repair of wounds (R).

10) L. reuteri Protects Against Infections

L. reuteri potently protects against Salmonella, cutting mortality rates in mice, chickens, and turkeys in half (R).

In chickens, L. reuteri was as potent as the antibiotic gentamicin in preventing E. coli-related deaths (R).

An antibiotic produced by L. reuteri, called reutericyclin, can kill C. difficile infections (R).

Derivatives of L. reuteri are helpful for MRSA on the skin, destroying biofilms and reducing the infection (R).

A 2-week treatment with L. reuteri DSM17648 significantly reduced H. pylori overgrowth in otherwise healthy adults (R).

11) L. reuteri Promotes Oral Health

L. reuteri fights major cavity-producing bacteria (R).

Chewing gum containing L. reuteri decreased plaque and bleeding from the gums in two weeks (R).

Oral L. reuteri containing tablets significantly reduced inflammation markers (TNF-α, IL-1β, and IL-17) in patients with chronic periodontitis (R).

L. reuteri lozenges were shown to fight oral candida in a study of older patients (R).

12) L. reuteri Produces Vitamin B12

L. reuteri CRL1098, a strain of L. reuteri isolated from sourdough, has been shown to produce cobalamin, otherwise known as vitamin B12 (R).

13) L. reuteri May Help in Autism

In an animal model of social deficits in offspring, L. reuteri was found to be 9X lower.  Supplementing with it significantly improved sociability and preference for social novelty in these offspring (R).

The main mechanism is by l reuteri increasing oxytocin, including in the hypothalamus (R).

L. reuteri is Controversial When it Comes to Obesity

L. reuteri GMNL-263 has proved to be effective in reducing both insulin resistance and fatty liver in rats (R).

An animal study showed L. reuteri strain ATCC PTA 4659 to partly prevent weight gain caused by an unhealthy Western diet (R).

In a study of both humans and mice, a Western ‘fast food’ diet caused changes in gut bacteria, accumulation of belly fat and Th17 dominance. The addition of Lactobacillus reuteri ATCC 6475 with no change in diet prevented age-associated weight gain by reducing the Th17 inflammation (R).

Or, L. reuteri may cause obesity, in this study of an unspecified strain, the results of which requires caution, since it is the first to connect that species of bacteria with obesity (R).

Additional Reading

Buy Lactobacillus reuteri

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  • Simon

    The product is called Gastrus.
    The brand is Biogaia, a Swedish company.
    You can buy it on internet by the company iHerb.
    The line is Belgium-Sweden-USA.

  • Christine

    Yeah, this is incredibly sloppy. Not even the right strain…makes me almost think you were paid off to promote this or something.

  • andreia

    Probably not – the benefits are strain specific – you have to look for the number after the name Lactobacillus reuteri. Most of the research I´ve seen is done with L.reuteri DSM 1793 . But it is not recommended for those with histamine intolerance issues.

  • andreia

    I took the L.reuteri in the probiotic (Nature´s Way) you recommended but it have me terrible gas, constipation and reflux. Turns out it´s got two other strains besides L.reuteri: L. acidophillus and L. rahmnosus, both of which are also known to cause histamine intolerance. But what makes matters worse is that it has got FOS (fructooligosaccharide), a prebiotic that is strictly forbidden for those who have FODMAP intolerance. Maybe a better choice for those who want to try L.reuteri would be the one produced by Biogaia (L. reuteri DSM 1793), probably the L.reuteri strain with more research behind it (not all L.reuteri are equal,”Lactobacillus” and ” reuteri” refer to the genus and species, the number is what identifies the strain) – the benefits are strain-specific. I took L. reuteri DSM 1793 and didn´t have the side-effects experienced with the Nature´s way brand, to which my son also had a terrible reaction (green watery diarrhea) when he was a baby.

  • Andre du Toit

    Hi Stephen, I also have a son (age 13) with high functioning autism. He takes a variety of probiotics with good results for his slow bowl. According to my observation, his anxiety is also improving. How is your son doing?

  • Taison

    I have been taking the BioGaia Protectis for babies and it has lowered my social anxiety.
    Good luck.

  • janet

    So does it increase weight or not – I have Microbiome one that comes in two tablets one with the probiotic in and one with the prebiotic in so you take two tablets and I have Custom Pro L. Reuteri – I need to know does this probiotic increase weight because I don’t want to take it if it does but it is good for lowering cholesterol which is good

  • Vonda

    Nature’s Sunshine carries it. They are a company that does pharmaceutical grade supplements and are excellent! You’re going to have to find a health food store that carries this brand.

  • Jame Gumb

    “L. reuteri switches our bacteria’s primary food source from sugar to tryptophan”

    I couldn’t find any information on Reuteri globally shifting food supply from dietary sugars to Tryptophan. Just that reuteri itself uses Tryptophan.

  • steve

    I recently started seeing Reuteri recommended for social anxiety but all the products mention it is for cardio health.
    That Nature’s Way brand contains fos which many including myself can’t handle. I’m searching for another brand although I wonder if it is a particular strain that is good for social anxiety

  • Stephen Kastl

    I have used biogaia brand called ProTectis on my high functioning autistic son. He is definitely more social but it is not a magic bullet since he also argues better and try to talk me out of his daily exercise. He is 25, and 6’2″ tall. I give him one with each meal. I will increase dosage and see.

  • Morrigan

    Is it in kraut? Yogurt? How can you get this from food rather than taking a pill?

  • GM

    It’s confusing that none of supplements are of the variety studied in papers! Not good… makes the research borderline useless.

  • Graeme

    There is an awesome new study showing that this may be helpful in autism –

    1. Joseph M. Cohen


  • William Gleason

    No one knows if it is in Sauerkraut.

  • Brandon Gregg

    How does one get all these different strains in one pill? If I see L. reuteri listed in the ingredients, it never says which strains.

  • Melissa Christie

    should it be refridgerated kind to buy, someone noted Amazon stocks it unrefridgerated and the live cultures would be dead when you receive the order, is that true, what do you use ?
    Thank you 🙂

    1. Melissa Christie

      could you recomened which one to use please

      1. Joseph M. Cohen

        I think it’s pretty stable, but if you’re worried, then go for the iherb one.

        1. Melissa

          Thank you !

  • Thomas

    is it in sauerkraut?

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