11 Lactobacillus Reuteri Health Benefits


Lactobacillus Reuteri is a gram positive bacili shaped probiotic strain that can be found in the gastrointestinal tract, urinary tract, skin and even in breast milk. It is non-spore forming.

Lactobacillus Reuteri is able to survive in low-pH and enzyme rich environments ensuring the strain has a higher chance of multiplying and reaching deep enough into the intestines.

L. Reuteri was originally thought to be Lactobacillus Fermentum until a man by the name of Gerhard Reuter discovered and named the strain after himself.


There are only a handful of good quality studies for Diverticulitis out there at the time of writing this in March 2022. Interestingly however one of the best was Lactobacillus Reuteri.

This study tested Lactobacillus Reuteri ATCC PTA 4659's effects on 88 male and female paitent's who were diagnosed with Acute Uncomplicated Diverticulitis. The study was a double-blind placebo controlled study.

Group had 44 participants take ciprofloxacin & metronidazole for one week and then L. Reuteri for 10 days. Group B had 44 participants take the same antibiotics but instead of L. Reuteri for 10 days, they took a placebo.

The study was carried out well and it was easy enough to see if the L. Reuteri strain worked or not. Compared to the placebo group taking the antibiotic's with L. Reuteri significantly reduced abdominal plain and inflammatory markers. The L. Reuteri group also required shorter hospitilaztion. 

The reason L. Reuteri seemed to have helped was because of the anti-inflammatory effect which is common and documented with a number of other Lactobacillus probiotic strains. (1)

Hair Health

The Lactobacillus Reuteri TCC PTA 6475 probiotic strain in this study was used on mice during separate gastrointestinal studies but amazingly the scientists discovered that mice taking the probiotic strain exhibited more lustrous fur compared to other mice they had seen.

Initially they planned to feed a group of mice L. Reuteri starting at 20 - 24 weeks of age and then planned to check fur luster, pH readings and histology. Scientists were surprised when at just 7-days of eating the yogurt, the control group of mice had differences in fur luster.

Mice that ate just a normal bland diet were said to have dull fur luster and even so alopecia along with dermatitis. The fur benefits were more pronounced in female mice and the had more acidic pH.

It is thought that the reason for the hair benefits was because of the L. Reuteri probiotic strain blocking High IL-17 inflammation. Other Lactobacillus bacteria like L. Salivarius have also shown to have anti-inflammatory effects. Unfortunately this same study has not been clinically carried out on human's yet. (2)


The use of probiotic supplementation for the purpose of boosting testosterone isn't that common and there have not been many studies testing if probiotic bacteria can help.

In fact the reason for the conducting study I am going to share was brought about by chance. In previous studies mice were noted to have unusually large testes and social dominance behaviours after being fed probiotic yogurts and pure lactic acid bacteria.

This led to a study being published in 2014 from Massachusetts, United States of America. It looked at if supplementation of L. Reuteri on mice could increase testosterone and the results were interesting.

They started feeding a control group of mice from as young as 2-months old Lactobacillus Reuteri ATCC 6475 probiotic bacteria. During month 3,5,7 and 10 months this control group of mice had larger & heavier testes compared to a group following the same diet without L. Reuteri bacteria.

The study is long and there is a lot information in it and further on in the study it stated that "L. reuteri may provide an alternative natural approach to the prevention of late-onset male hypogonadism (low-libido)" meaning that potentially there could still be testosterone benefits taking L. Reuteri at any age but keep in mind this study was carried out on mice and not clinically on humans. (3)


The use of Lactobacillus Reuteri for IBS and IBD has been contested in the past. One study from 2015, took 54 participants with IBS to test Lactobacillus Reuteri ATCC 55730 in a 6-month double-blind placebo study. Unfortunately only 39 ended up completing the study and the results showed no difference between the placebo and L. Reuteri groups for improvements with IBS and IBD. (4)

Another more complex study in 2015 found that Lactobacillus reuteri RC-14 along with Lactobacillus rhamnosus GR-1 was able to increase T-Cells and decrease inflammation in paitents who had Inflammatory Bowel Disease. The scientists had a thoery that L. Reuteri may have helped convert sugar to tryptophan which may have helped with serotonin production in the gut. (5)


I have featured several probiotic strains previously that have shown benefits for cholesterol and it has been studied many times.

This study conducted on humans was a nice and simple double-blind placebo study that 114 hypercholesterolaemic subjects completed as directed. Half of the group were randomly given yogurt containing Lactobacillus reuteri NCIMB 30242 probiotic bacteria.

Half of the subjects were told to eat the yogurt twice per day for a total of 6-weeks while another half ate the yogurt without the L. Reuteri probiotic strain or any other probiotic bacteria.

At the end of the 6-weeks those had unwittingly ingested the L. Reuteri yogurt had lower LDL-cholesterol, Total Cholesterol and non-HDL-cholesterol.

It's worth noting that he Lactobacillus Reuteri was microencapsulated which made sure it passed through the digestive tract and the total CFU count was not mentioned so we don't know what CFU count is best for cholesterol. (6)

Eczema (Atopic Dermatitis)

This study took children aged 1 to 13 years old suffering with Atopic Dermatitis and had them take probiotics for 6-weeks in hopes that it would help.

The two strains chosen to give to the children were Freeze Dried Lactobacillus rhamnosus 19070-2 and Lactobacillus reuteri DSM 122460. They were freeze dried to ensure maximum potency of the bacteria.

Markers related to pro-inflammatory cytokines were recorded and so was atopic dermatitis scoring system. Eosinophil cationic protein in serum & cytokine production by PBMCs were the inflammatory markers measured.

The study was a double-blind placebo controlled study so some of the kids were given the L. Reuteri / L. Rhamnosus bacteria strains and others were given a placebo.

After 6-weeks 56% of those given the probiotic bacteria had improvements with their Eczema vs just 15% in the placebo group.

The kids in this study who had eczema from allergies (confirmed by skin prick test) experienced more pronounced improvements according to the study. (7)

H. Pylori

This excellent human study reduced overgrowth of H. Pylori using Lactobacillus Reuteri Lactobacillus reuteri DSM17648 probiotic strain.

700 other strains were tested but Lactobacillus Reuteri DSM21031 was one of only three able to co-aggregate with the spiral forms of H. Pylori. (8)

Another study was also confirmed that L. Reuteri helped by decreasing the symptoms of H. Pylori infection and the bacterial load. It's thought this was possible because the L. Reuteri probiotic bacteria was able to compete and win against the H. Pylori bacteria. (9)

Vitamin D

Vitamin D is important for a whole range of different things and L. Reuteri NCIMB 30242 was tested to check if taking it orally would be able to increase 25-hydroxy vitamin D in the human body.

This double-blind placebo randomized controlled trial recruited 127 subjects from Prague, Czech Republic and one group took L. Reuteri NCIMB 30242 probiotic capsules over a 63-days.

The conclusion of the study was that L. Reuteri NCIMB 30242 did seem to increase 25-hydroxyvitamin D by 25.5%. That may sound impressive but the placebo group also increased by 22.4%. (10)

Vaginal Health (Candida)

This study simulated vaginal candidiasis in a vitro model. The epithelial cell line (VK2/E6E7) was purposely infect with C. albicans 3153a to start the experiment.

The scientists then used a combination of L. rhamnosus GR-1 and L. reuteri RC-14 either combined, mixed or alone.

The amount of yeast and cytokine levels were measured at various intervals to check if the probiotic bacteria was killing off the yeast.

It was noted that both L. Rhamnosus and L. Reuteri together were able to decrease the yeast population and the cell based test concluded that both strains may inhibit yeast growth. (11)

Oral Health

Gabriela Sinkiewicz from the Department of Biomedical Laboratory Science, Health and Society, Malmö University, Malmö, Sweden has studied Lactobacillus Reuteri in the past quite extensively.

In one of her studies, Gabriela noted that L. Reuteri Plaque and Bleeding from the gums declined after only 2-weeks of L. Reuteri usage but not much more information was available. 

Other Lactobacillus bacteria have been studied for dental health and some positive results have been shown for things like periodontitis. More human studies are needed for L. Reuteri to figure out if the strain can be truly beneficial for L. Reuteri. (12)

Leaky Gut

This 2018 study claimed that while the effects of Lactobacillus Reuteri are still not fully clear the mucosal barrier is important for protection agains't leaky gut syndrome. They claimed the L. Reteuri strain may have benefits via a protective effect on bacteria induced leaky gut.

Enterotoxigenic Escherichia coli (ETEC) bacteria is thought to be one common cause of intestinal permeability that leads to leaky gut and it was hypothesized that the L. Reteuri strain could protect the mucosal barrier from this strain.

L. reuteri DSM 17938 was used in a vitro setting and not tested in humans with leaky gut. The conclusion of the study was that the probiotic strain was able to increase permeability and slow down damage to the intestinal barrier from the ETEC bacteria.

L. Reuteri Side Effects

There are no clinical human studies showing the long-term effects of supplementation of Lactobacillus Reuteri probiotic bacteria.

Some people may experience bloating, gas, diarrhea and other unpleasant digestive symptoms when taking probiotic supplements for the first time. Immuno comprimised people should never take probiotic supplements.

There were some studies that showed people gained weight after taking L. Reuteri in studies so weight gain could be another side effect. There are far better strains for weight loss and L. Gasseri is one of them.

In all of the studies in this blog post there were no serious side effects reported and some studies even claimed that Lactobacillus Reuteri was safe for consumption.

As always, if you experience any side effects, discontinue use of your probiotic supplement and consult with a Doctor. I am not a Doctor and this content is not medical advice.

L. Reuteri Foods

Lactobacillus bacteria can be found in a variety of fermented and dairy foods. Lactobacillus Reuteri may be found in the following foods.

  • Sourdough Bread
  • Yogurt
  • Sauerkraut
  • Kefir Milk
  • Kimchi

If you want to know the specific Colony Forming Units of Lactobacillus Reuteri and be sure that you 100% ingest the L. Reuteri strain then probiotic supplementation may be the best thing do.

Final Thoughts

Lactobacillus Reuteri has to be one the most studied probiotic strains out there 2022. It's quite rare to even though the origin's of who discovered a bacteria strain.

All credit goes too Gerhard Reuter and it's a shame that there isn't more information out there on him.

It's undeniable that there are some health benefits from Lactobacillus Reuteri and that it's safe enough to use in supplements.

L. Reuteri should never be used as a replacement to any prescribed medication. Many studies used the strain along side other medications and the human participants were always monitored by Doctors.


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