# Lactobacillus reuteri DSM 17938

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/lactobacillus-reuteri-dsm-17938
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-03-18
**Evidence Score:** 8 / 10
**Category:** Fermented/Probiotic
**Also Known As:** Lactobacillus reuteri DSM 17938, L. reuteri DSM 17938, BioGaia strain, Protectis strain, DSM 17938, L. reuteri Protectis, Human-derived L. reuteri

## Overview

Lactobacillus reuteri DSM 17938 is a clinically studied probiotic strain that produces reuterin, an antimicrobial compound that helps balance gut microbiota. This strain modulates [immune function](/ingredients/condition/immune-support) through toll-like receptor signaling and supports digestive health by enhancing [intestinal barrier integrity](/ingredients/condition/gut-health).

## Health Benefits

- Supports [digestive health](/ingredients/condition/gut-health) by balancing the gut microbiota, which is crucial for nutrient absorption and overall well-being. - Enhances [immune function](/ingredients/condition/immune-support), reducing the risk of infections by increasing the production of protective antibodies. - Promotes mental well-being by influencing the gut-brain axis, potentially alleviating anxiety and depression. - Aids in weight management by regulating fat storage and energy expenditure, supporting a healthy body weight. - Improves [skin health](/ingredients/condition/skin-health) by reducing systemic [inflammation](/ingredients/condition/inflammation), which can alleviate conditions like acne and eczema. - Supports [cardiovascular health](/ingredients/condition/heart-health) by reducing cholesterol levels, lowering the risk of heart disease. - Enhances [energy metabolism](/ingredients/condition/energy) by breaking down complex carbohydrates, improving energy levels and endurance.

## Mechanism of Action

Lactobacillus reuteri DSM 17938 produces reuterin (3-hydroxypropionaldehyde) from glycerol, which exhibits broad-spectrum [antimicrobial](/ingredients/condition/immune-support) activity against pathogenic bacteria while preserving beneficial microbes. The strain activates toll-like receptors (TLR2/TLR4) on intestinal epithelial cells, triggering [anti-inflammatory](/ingredients/condition/inflammation) cytokine production including IL-10. It also strengthens tight junction proteins like claudin-1 and occludin, improving intestinal barrier function and reducing inflammatory responses.

## Clinical Summary

Multiple randomized controlled trials have demonstrated the efficacy of L. reuteri DSM 17938, particularly in pediatric populations. Studies with 50-400 participants show significant reduction in infantile colic crying time by 50-80% within 21 days of supplementation. Adult trials (n=100-200) demonstrate improved digestive symptoms and reduced [inflammatory](/ingredients/condition/inflammation) markers after 4-8 weeks of daily administration. The evidence is strongest for gastrointestinal applications, with emerging research on immune and neurological benefits showing promising but preliminary results.

## Nutritional Profile

- Contains live [probiotic](/ingredients/condition/gut-health) cultures. - Produces lactic acid, supporting gut health. - Rich in bioactive compounds that modulate the [immune system](/ingredients/condition/immune-support).

## Dosage & Preparation

Typical dosage ranges from 1 to 10 billion CFU per day. Consult a healthcare provider before use.

## Safety & Drug Interactions

Lactobacillus reuteri DSM 17938 is generally well-tolerated with minimal reported adverse effects, primarily mild digestive symptoms during initial use. No significant drug interactions have been documented, though individuals taking immunosuppressive medications should consult healthcare providers before use. The strain is contraindicated in severely immunocompromised patients and those with central venous catheters due to rare risk of bacteremia. Safety during pregnancy and lactation appears favorable based on limited studies, but more research is needed for definitive recommendations.

## Scientific Research

Lactobacillus reuteri DSM 17938 has been studied in multiple RCTs, showing efficacy in supporting digestive and immune health. Meta-analyses confirm its benefits in various health conditions.

## Historical & Cultural Context

Discovered in the late 20th century, Lactobacillus reuteri DSM 17938 is a well-researched [probiotic](/ingredients/condition/gut-health) strain used in supplements and functional foods.

## Synergistic Combinations

[Prebiotic](/ingredients/condition/gut-health) Fiber,Omega-3 Fatty Acids,Vitamin D

## Frequently Asked Questions

### Does Lactobacillus reuteri DSM 17938 help with infant colic?

Lactobacillus reuteri DSM 17938 is one of the most researched probiotics for infant colic. Multiple randomised controlled trials and meta-analyses have demonstrated that supplementation can significantly reduce daily crying time in breastfed infants compared to placebo. The proposed mechanism involves modulation of gut microbiota balance through reuterin production and reduction of intestinal inflammation via toll-like receptor signalling. Standard dosing in infant studies typically uses around 100 million CFU per day. Always consult a paediatrician before giving any supplement to an infant.

### Can Lactobacillus reuteri DSM 17938 help reduce cholesterol levels?

Research suggests Lactobacillus reuteri DSM 17938 may support cardiovascular health by modestly reducing LDL and total cholesterol levels. The mechanism is thought to involve bile salt hydrolase activity, which interferes with bile acid reabsorption in the gut, prompting the liver to use circulating cholesterol to synthesise new bile acids. Clinical studies have reported reductions in LDL cholesterol with regular probiotic use. While results are promising, this strain should complement, not replace, a heart-healthy diet and any prescribed lipid-lowering therapy.

### Does Lactobacillus reuteri DSM 17938 improve symptoms of irritable bowel syndrome (IBS)?

Lactobacillus reuteri DSM 17938 may help alleviate IBS symptoms including bloating, abdominal discomfort, and irregular bowel habits. Its mechanism includes strengthening intestinal tight junction proteins such as claudin-1 and occludin, which reduces gut permeability and systemic inflammation. Additionally, reuterin production helps rebalance dysbiotic microbiota commonly observed in IBS patients. Anti-inflammatory cytokine IL-10 upregulation via TLR signalling also helps dampen gut hypersensitivity. Clinical evidence is supportive, though response can vary between IBS subtypes. A dosage of 1–10 billion CFU daily is typically studied.

### Can I take Lactobacillus reuteri DSM 17938 alongside antibiotics?

Taking Lactobacillus reuteri DSM 17938 during antibiotic treatment is commonly recommended to help prevent antibiotic-associated diarrhoea and reduce dysbiosis. However, antibiotics can kill live probiotic bacteria, so it is generally advised to separate doses by at least 2 hours. Resuming consistent supplementation after completing the antibiotic course may help restore gut microbiota balance more quickly. The strain's reuterin-mediated antimicrobial selectivity helps preserve beneficial bacteria. Always consult a healthcare provider for personalised guidance when combining probiotics with antibiotic regimens.

### Does Lactobacillus reuteri DSM 17938 support mental health and reduce anxiety?

Lactobacillus reuteri DSM 17938 may positively influence mental well-being through the gut-brain axis. This bidirectional communication pathway involves vagal nerve signalling, immune modulation, and neurotransmitter production. By reducing gut inflammation via IL-10 induction and improving intestinal barrier integrity, this strain may lower systemic inflammatory signals that are increasingly linked to anxiety and depressive symptoms. While preclinical and emerging clinical data are encouraging, human evidence remains preliminary. This probiotic should be viewed as a supportive tool alongside conventional mental health care, not a standalone treatment.

### What are the potential side effects of Lactobacillus reuteri DSM 17938?

Lactobacillus reuteri DSM 17938 is generally considered safe and well-tolerated across a broad population including infants, children, and adults. The most commonly reported side effects are mild and transient, including bloating, gas, or loose stools, particularly during the first few days of supplementation as the gut microbiota adjusts. Serious adverse events are rare and typically reported only in immunocompromised individuals. As with any probiotic, people with severe immune conditions, central venous catheters, or critical illness should seek medical guidance before use.

### Can Lactobacillus reuteri DSM 17938 help with skin conditions like acne or eczema?

Lactobacillus reuteri DSM 17938 may benefit inflammatory skin conditions such as acne and eczema through its systemic anti-inflammatory effects. By activating TLR2/TLR4 signalling to promote IL-10 production and reducing intestinal permeability, this strain may lower the systemic inflammatory burden that contributes to skin flare-ups. Improved gut microbiota balance can also reduce circulating endotoxins that trigger inflammatory cascades. While direct dermatological trials are limited, the gut-skin axis mechanism provides a plausible pathway. A dosage of 1–10 billion CFU daily is typical; consult a dermatologist for personalised care.

### How should Lactobacillus reuteri DSM 17938 be stored to maintain potency?

Proper storage is critical to maintaining the viability of Lactobacillus reuteri DSM 17938. Most formulations are best stored in a cool, dry place away from direct sunlight and humidity; refrigeration is commonly recommended unless the product is specifically labelled shelf-stable. Exposure to heat, moisture, or prolonged air contact can significantly reduce CFU counts. Always check the product label for manufacturer-specific storage instructions and use before the expiry date. Travel-sized or blister-packed formulations may offer improved stability at ambient temperatures compared to loose powder or open capsule formats.

### What is the effective dosage of Lactobacillus reuteri DSM 17938?

Clinical studies typically use doses of 1×10^8 CFU daily for adults and 1×10^8 CFU daily for infants. Most commercial supplements provide this dosage in 5-10 drops of oil suspension or one capsule. Treatment duration ranges from 21 days to 12 weeks depending on the condition being addressed.

### How long does it take for Lactobacillus reuteri DSM 17938 to work?

Effects on digestive symptoms typically appear within 7-14 days of consistent use, with maximum benefits observed after 21 days. For immune system support, clinical improvements may take 4-8 weeks. Individual response varies based on baseline gut microbiota composition and overall health status.

### Can Lactobacillus reuteri DSM 17938 survive stomach acid?

This strain demonstrates good acid tolerance and can survive gastric transit to reach the intestines viable. Studies show approximately 10-30% of ingested bacteria remain viable after passing through stomach acid. Taking with food may further improve survival rates through buffering stomach pH.

### Is Lactobacillus reuteri DSM 17938 safe for infants?

Yes, extensive clinical research supports safety in infants as young as newborns, with over 1,000 infants studied across multiple trials. The strain is naturally found in human breast milk and has GRAS (Generally Recognized as Safe) status. No serious adverse events have been reported in pediatric studies.

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*Source: Hermetica Superfoods Ingredient Encyclopedia — https://ingredients.hermeticasuperfoods.com*
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