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Limosilactobacillus reuteri DSM 17938 (BioGaia Protectis®)

Limosilactobacillus reuteri DSM 17938 (formerly Lactobacillus reuteri DSM 17938)
Evidence Level
Strong
3 Clinical Trials
7 Documented Benefits
4/5 Evidence Score

Limosilactobacillus reuteri DSM 17938 is a specific probiotic strain marketed as BioGaia Protectis® — one of the most clinically studied strains for infant and pediatric gastrointestinal conditions. It has the strongest evidence base for reducing infant colic crying time in breastfed infants, with multiple randomized trials and meta-analyses showing roughly 50% reductions in daily crying. Also has evidence for functional abdominal pain in children, antibiotic-associated diarrhea prevention, and Helicobacter pylori adjunct support. In adults, evidence extends to constipation and certain GI conditions but is less robust than the pediatric data. The honest framing: this is one of the better-evidenced probiotic strains for specific pediatric indications — particularly breastfed infant colic — and a reasonable choice for adult digestive support, though the adult evidence is more variable.

Studied Dose Infants: 100 million CFU (1×10⁸) once daily as drops (BioGaia Protectis® dosing). Children: 100-400 million CFU/day. Adults: 100 million to 1 billion CFU/day. Take 2-3 hours apart from antibiotics. Refrigerate after opening for live forms.
Active Compound Limosilactobacillus reuteri DSM 17938 (recently reclassified from Lactobacillus reuteri DSM 17938). Daughter strain of L. reuteri ATCC 55730 (parent strain) — antibiotic-resistance genes were removed by genetic modification. Trademark of BioGaia AB

Benefits

Infant colic crying time reduction

Multiple randomized trials in breastfed infants show that L. reuteri DSM 17938 reduces daily crying time roughly 50% versus placebo over 21-28 days. The strongest single-supplement evidence for infant colic. Effects are smaller and less consistent in formula-fed infants.

Supported by Trial 1, Trial 3

Functional abdominal pain in children

Randomized trials in children with functional abdominal pain show reduced pain intensity and frequency over 4 weeks of supplementation. Effect sizes are moderate but clinically meaningful for a condition with few good interventions.

Supported by Trial 2

Antibiotic-associated diarrhea prevention

L. reuteri DSM 17938 reduces the risk of antibiotic-associated diarrhea in adults and children. Effect sizes are modest but consistent across trials. Take 2-3 hours apart from the antibiotic dose to preserve probiotic viability.

Supported by Trial 1

H. pylori eradication adjunct

Used alongside standard triple therapy for H. pylori infection, L. reuteri DSM 17938 reduces side effects of antibiotic therapy and may modestly improve eradication rates. Adjunct support rather than standalone treatment.

Supported by Trial 1

Functional constipation in children

Some randomized trials in pediatric functional constipation show improved stool frequency with L. reuteri DSM 17938 over weeks of use. Evidence is mixed across trials; not all studies have shown benefit.

Supported by Trial 1, Trial 2

Adult digestive comfort and bloating

Emerging evidence in adults with mild digestive symptoms shows reductions in bloating and improved comfort over 4-8 weeks. Adult evidence is less robust than pediatric, but the safety profile makes it a reasonable trial.

Supported by Trial 1, Trial 2

Oral health support (separate strain product)

Specific Lactobacillus reuteri strains in lozenges (different products from BioGaia Protectis®) have evidence for gingivitis and periodontal health. Different formulation; oral health products use different strains and delivery formats.

Supported by Trial 1

Mechanism of action

1

Reuterin antimicrobial production (distinguishing)

Reuterin (3-hydroxypropionaldehyde) is a broad-spectrum antimicrobial active against bacteria, fungi, and protozoa. Produced by L. reuteri species — the distinguishing mechanism among Lactobacillus species.

2

Gut motility modulation

DSM 17938 modulates gut motility — increasing motility in constipation and reducing visceral effects in colic. Mechanism shared across the constipation and colic indications.

3

TLR2 immunomodulation

Toll-like receptor 2 (TLR2) immunomodulation supports the immune and anti-inflammatory effects.

4

Microbiota normalization in colic

Colicky infants have altered baseline microbiota; DSM 17938 contributes to microbiota normalization. Mechanism for the colic improvement beyond direct visceral effects.

5

Anti-inflammatory cytokine modulation

Cytokine modulation contributes to the broader anti-inflammatory effects.

6

Strain-specific safety engineering

DSM 17938 is the daughter strain of parent ATCC 55730 — antibiotic-resistance genes were genetically removed for safety. Reflects rigorous strain-specific safety engineering for an infant-exposed product.

Clinical trials

1
Xu 2015 — L. reuteri DSM 17938 Infantile Colic META-ANALYSIS (PMID 26509767, PIVOTAL)

Xu S et al. 2015 (PMID 26509767, PMC4624960, PLOS ONE 10(10):e0141445). Meta-analysis of 6 RCTs in 423 infants. Treatment effectiveness 2 weeks RR 2.84 (95% CI 1.24-6.50, p=0.014); 3 weeks RR 2.33 (95% CI 1.38-3.93, p=0.002). Crying time WMD -42.89 min/day at 2 weeks; -45.83 min/day at 3 weeks. No weight/length/head circumference influence. No serious adverse events.

2
PMC5758237 — Network META-ANALYSIS of 32 RCTs Infantile Colic (n=2,242)

PMC5758237 — network meta-analysis of 32 RCTs in 2,242 patients. Comparative superiority over diet, acupuncture, and other interventions for infantile colic.

3
Savino 2010 — Foundational Breastfed Colic RCT

Savino 2010 — foundational RCT in 50 exclusively breastfed colicky infants. 1×10⁸ CFU/day × 21 days. Established the standard 5 drops/day dose.

Side effects and drug interactions

Common Potential side effects

Generally extremely well-tolerated; extensive infant safety record.
NO weight, length, head circumference influence (Xu 2015 meta-analysis).
NO serious adverse events documented across multiple meta-analyses.
Mild GI upset (rare in infants).
Pregnancy/lactation: SAFE — frequently used during breastfeeding for both maternal and infant applications.
Long-term safety: extensive multi-meta-analytic evidence supportive.
Industry-sponsorship (BioGaia AB) — important context.

Important Drug interactions

Antibiotics: take 2-3 hours apart from L. reuteri DSM 17938 dose.
Most medications: well-tolerated combination profile.
Immunosuppressants: caution (applies to all probiotics; especially in infants).
Anticoagulants: no interactions documented.
Other probiotics: compatible.
Helicobacter pylori eradication therapy: ENHANCED outcomes per Francavilla 2008+ trials.
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Frequently asked questions about Limosilactobacillus reuteri DSM 17938 (BioGaia Protectis®)

What is Limosilactobacillus reuteri DSM 17938 (BioGaia Protectis®)?

Limosilactobacillus reuteri DSM 17938 is a specific probiotic strain marketed as BioGaia Protectis® — one of the most clinically studied strains for infant and pediatric gastrointestinal conditions.

What does Limosilactobacillus reuteri DSM 17938 (BioGaia Protectis®) do?

Reuterin (3-hydroxypropionaldehyde) is a broad-spectrum antimicrobial active against bacteria, fungi, and protozoa. Produced by L. reuteri species — the distinguishing mechanism among Lactobacillus species. In clinical research, Limosilactobacillus reuteri DSM 17938 (BioGaia Protectis®) has been studied for infant colic crying time reduction, functional abdominal pain in children, antibiotic-associated diarrhea prevention.

Who should take Limosilactobacillus reuteri DSM 17938 (BioGaia Protectis®)?

Limosilactobacillus reuteri DSM 17938 (BioGaia Protectis®) may be most relevant for people interested in gut health, immune support. It has been clinically studied for infant colic crying time reduction, functional abdominal pain in children, antibiotic-associated diarrhea prevention. As with any supplement, consult your healthcare provider before starting, especially if you have medical conditions or take prescription medications.

How long does Limosilactobacillus reuteri DSM 17938 (BioGaia Protectis®) take to work?

In clinical trials, effects have been measured at 2 weeks of consistent use. Acute or same-day effects (where applicable) typically appear within hours, but most cumulative benefits — particularly those affecting biomarkers, mood, sleep quality, or chronic symptoms — require 4-12 weeks of regular use to fully assess. If you don't notice benefit after 12 weeks at the appropriate dose, it may not be your responder.

When is the best time to take Limosilactobacillus reuteri DSM 17938 (BioGaia Protectis®)?

For gut health goals, Limosilactobacillus reuteri DSM 17938 (BioGaia Protectis®) can typically be taken with meals or as directed on product labeling. Some probiotic and digestive supplements are best taken on an empty stomach; others with food — follow product-specific guidance. Always check product labeling and follow personalized guidance from your healthcare provider.

Is Limosilactobacillus reuteri DSM 17938 (BioGaia Protectis®) worth taking?

Limosilactobacillus reuteri DSM 17938 (BioGaia Protectis®) has strong clinical evidence (Evidence Level 4/5 on NutraSmarts) for its primary uses, with multiple randomized controlled trials and meta-analyses supporting its benefits. Whether it's worth taking depends on your specific goals, what you've already tried, your budget, and your overall supplement strategy. The honest framing: no supplement is essential for most people, and lifestyle factors (sleep, exercise, diet, stress management) typically produce larger effects than any single supplement. Limosilactobacillus reuteri DSM 17938 (BioGaia Protectis®) is most worth trying if its evidence-supported uses align with your specific goals.

What is the recommended dosage of Limosilactobacillus reuteri DSM 17938 (BioGaia Protectis®)?

The clinically studied dose for Limosilactobacillus reuteri DSM 17938 (BioGaia Protectis®) is Infants: 100 million CFU (1×10⁸) once daily as drops (BioGaia Protectis® dosing). Children: 100-400 million CFU/day. Adults: 100 million to 1 billion CFU/day. Take 2-3 hours apart from antibiotics. Refrigerate after opening for live forms.. Always follow product labeling and consult a healthcare provider for personalized dosing recommendations.

What is Limosilactobacillus reuteri DSM 17938 (BioGaia Protectis®) used for?

Limosilactobacillus reuteri DSM 17938 (BioGaia Protectis®) is studied for infant colic crying time reduction, functional abdominal pain in children, antibiotic-associated diarrhea prevention. Multiple randomized trials in breastfed infants show that L. reuteri DSM 17938 reduces daily crying time roughly 50% versus placebo over 21-28 days. The strongest single-supplement evidence for infant colic.