Lactobacillus Reuteri
TL;DR
Lactobacillus reuteri is one of the better-studied probiotic species, with the strongest evidence for reducing crying time in colicky breastfed infants and modest support for gum health and H. pylori adjunct therapy.
Ideal For
- Parents of exclusively breastfed infants with colic
- People with gingivitis alongside standard oral hygiene
- People starting H. pylori eradication who want fewer antibiotic side effects
Avoid If
- You are significantly immunocompromised
- You have a central venous catheter or short bowel syndrome
- You are critically ill
Frequently Asked Questions
What is Lactobacillus reuteri used for?
Does it help colic?
What dose do adults use?
Does it lower cholesterol?
What about gum health?
Is it safe?
Overview
Lactobacillus reuteri (now Limosilactobacillus reuteri) is a native human gut and breast-milk inhabitant, which makes it unusual among commercial probiotics. Strain matters enormously. DSM 17938 is the workhorse strain behind the infant colic literature: multiple randomized trials and meta-analyses show it reduces daily crying time in exclusively breastfed colicky infants, with a smaller and less consistent effect in formula-fed infants. That is one of the few probiotic indications where the effect size is clinically meaningful and reproducible. Beyond colic, DSM 17938 combined with ATCC PTA 5289 has been studied for gingivitis and plaque, generally with small but positive results, and reuteri strains are used as adjuncts to H. pylori eradication where they mainly reduce antibiotic side effects rather than boosting cure rates. Claims around reuteri raising testosterone or oxytocin come from rodent work and have not been demonstrated in humans. The recent trend of home-fermenting reuteri yogurt at very high cell counts is not backed by clinical data and carries a real risk of contamination and SIBO-type symptoms in susceptible people.
How It Works
- Produces reuterin, a broad-spectrum antimicrobial that suppresses enteric pathogens
- Modulates gut motility and visceral sensitivity, the likely route to reduced infant crying
- Downregulates pro-inflammatory cytokines in intestinal and oral mucosa
- Colonizes oral biofilms, competing with periodontal pathogens
Benefits & Outcomes
No linked outcomes yet. Research is ongoing.
Supporting Research10 studies
Evaluation of an Immunomodulatory Probiotic Intervention for Veterans With Co-occurring Mild Traumatic Brain Injury and Posttraumatic Stress Disorder: A Pilot Study
Brenner LA
In a 31-veteran pilot of Lactobacillus reuteri in co-occurring mild TBI and PTSD, the probiotic was safe and feasible and was associated with a reduction in the inflammatory marker C-reactive protein and a blunted cortisol awakening response versus placebo; psychiatric symptom scores did not differ significantly.
The effect of oral supplementation with Lactobacillus reuteri or tilactase in lactose intolerant patients: randomized trial
Ojetti V, et al
Tilactase strongly improves both LBT results and gastrointestinal symptoms after lactose ingestion with respect to placebo. Lactobacillus reuteri also is effective but lesser than tilactase.
Lactobacillus reuteri to Treat Infant Colic: A Meta-analysis
Sung V, D'Amico F, Cabana MD
L. reuteri DSM 17938 was effective in reducing crying time in breastfed infants with colic, but effects in formula fed infants were unclear.
Treating infant colic with the probiotic Lactobacillus reuteri: double blind, placebo controlled randomised trial
Sung V, Hiscock H, Tang MLK
L. reuteri did not benefit a community sample of breastfed and formula fed infants with colic.
Cholesterol lowering and inhibition of sterol absorption by Lactobacillus reuteri NCIMB 30242: a randomized controlled trial
Jones ML, Martoni CJ, Prakash S
L. reuteri NCIMB 30242 reduced LDL-cholesterol by 11.64% relative to placebo over nine weeks.
Lactobacillus reuteri DSM 17938 in infantile colic: a randomized, double-blind, placebo-controlled trial
Savino F, Cordisco L, Tarasco V
Median daily crying time at day 21 was significantly reduced in the L. reuteri group compared with placebo.
Efficacy and Safety of Postbiotic Contained Inactivated Lactobacillus reuteri (Limosilactobacillus reuteri) DSM 17648 as Adjuvant Therapy in the Eradication of Helicobacter pylori in Adults With Functional Dyspepsia: A Randomized Double-Blind Placebo-Controlled Trial.
Ivashkin V, Maev I, Poluektova E +1 more
Eradication efficiency was 96.7% for the postbiotic group vs 86.0% for the placebo group (P = 0.039).
Lactobacillus reuteri strain combination in Helicobacter pylori infection: a randomized, double-blind, placebo-controlled study
Francavilla R, Polimeno L, Demichina A
L. reuteri supplementation reduced Helicobacter pylori bacterial load and treatment-related side effects.
Probiotic containing Lactobacillus reuteri DSM 17648 as an adjunct treatment for Helicobacter pylori infection: A randomized, double-blind, placebo-controlled trial.
Ismail NI, Nawawi KNM, Hsin DCC +1 more
The eradication rate was higher in the probiotic group than in the placebo group, with a 22.2% difference in the intention-to-treat analysis (91.1% vs. 68.9%; p = 0.007).
Role of Lactobacillus reuteri in Human Health and Diseases
Mu Q, Tavella VJ, Luo XM
L. reuteri produces reuterin and modulates host immunity, with clinical effects that are strongly strain specific.
Safety Information
Potential Side Effects
Generally very well tolerated. Transient gas or loose stools in the first days. Rare bacteremia reports are confined to severely immunocompromised or catheterized patients.
Contraindications
Severe immunosuppression, indwelling central lines, critical illness.
Drug Interactions
- Antibiotics — separate doses by 2-3 hours
Pregnancy & Breastfeeding
Pregnancy: Likely safe
Breastfeeding: Likely safe
Dosage Guidelines
Dosage Used in Studies
Consult healthcare provider
Dosing by Goal
| Goal | Dose | Notes |
|---|---|---|
| Adult gut | 1x10^8 to 1x10^9 CFU daily | |
| Oral health | 1-2x10^8 CFU chewable twice daily for 4-12 weeks | |
| Infant colic | 1x10^8 CFU (5 drops) once daily for 21-28 days |
Forms Compared
Oil drops (DSM 17938)
The format used in nearly all infant colic trials
Chewable tablets
Used in the gum-health studies; designed for oral cavity contact
Capsules
General gut use; check the strain code, not just the species
Food & Timing
Timing is not critical; chewables for gum health should be taken after brushing and allowed to dissolve.
Medical Disclaimer
The information provided on this website is for educational and informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any supplement regimen.
Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.