Lactobacillus reuteri DSM 17938
Also known as: L. reuteri DSM 17938, Lactobacillus reuteri Protectis, L. reuteri 17938
Effective Dosage
1×10⁸ CFU daily (children); higher doses used in some emergency settings
What the Science Says
Lactobacillus reuteri DSM 17938 is a specific probiotic bacterial strain — a live microorganism that, when consumed in adequate amounts, benefits gut health. In children, it has been shown to meaningfully shorten the duration of acute diarrhea (by roughly 12–24 hours) and reduce stool frequency compared to placebo. Remarkably, one long-term follow-up study found that early supplementation in infancy was associated with dramatically lower rates of functional abdominal pain at age 10. Early use during infancy appears to be the most impactful window, though it has also shown promise in reducing post-surgical inflammation in dental procedures.
What It Doesn't Do
Not proven to treat adult digestive conditions — most evidence is in children under 5. Won't cure Alzheimer's disease; the rat study showing brain benefits has no human data behind it. No solid evidence it prevents tooth decay on its own. Don't expect it to work for every type of diarrhea — results in some trials were modest. Not a replacement for oral rehydration therapy in dehydrated children.
Evidence-Based Benefits
Lactobacillus reuteri DSM 17938 is a specific probiotic bacterial strain — a live microorganism that, when consumed in adequate amounts, benefits gut health. In children, it has been shown to meaningfully shorten the duration of acute diarrhea (by roughly 12–24 hours) and reduce stool frequency compared to placebo. Remarkably, one long-term follow-up study found that early supplementation in infancy was associated with dramatically lower rates of functional abdominal pain at age 10. Early use during infancy appears to be the most impactful window, though it has also shown promise in reducing post-surgical inflammation in dental procedures.
Moderate EvidenceEffective at: 1×10⁸ CFU daily (children); higher doses used in some emergency settings
Source: auto-research
Absorption & Bioavailability
Unknown in traditional absorption terms — as a live bacterial strain, 'bioavailability' refers to survival through the GI tract. Studies show clinical effects at 1×10⁸ CFU, suggesting adequate gut colonization at standard doses. No pharmacokinetic data provided.
Red Flags to Watch For
- Most strong evidence is in infants and young children — adult benefits are largely extrapolated or unproven in the provided studies
- One dental surgery trial was open-label and non-blinded, limiting reliability of those findings
- The Alzheimer's rat study is pre-clinical only — no human cognitive benefit data exists in the provided papers
- Some diarrhea trials had small sample sizes (as few as 48 participants), which limits confidence in effect sizes
- Products vary widely in CFU count and viability — many supplements may not deliver the doses used in studies
Products Containing Lactobacillus reuteri DSM 17938
See how Lactobacillus reuteri DSM 17938 is used in these analyzed products:
Research Sources
- PubMed
- NIH DSLD
This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Last updated: 2026-04-10