Lactobacillus fermentum
Research reviewed: Up until 03/2026
Lactobacillus fermentum (Limosilactobacillus fermentum) is a dietary supplement with 7 published peer-reviewed studies involving 510 participants, researched for Immune & Respiratory Health, Gut Health, Cholesterol & Metabolic Health.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Immune & Respiratory Health
StrongGut Health
ModerateCholesterol & Metabolic Health
ModerateResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Immune & Respiratory Health
To evaluate L. fermentum VRI-003 on respiratory illness in male distance runners.
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate L. fermentum VRI-003 on respiratory illness in male distance runners.
Dose
2 × 10^9 CFU/day
Participants
20 healthy male distance runners
Duration
4 months (winter training)
Results
L. fermentum significantly reduced number of days with respiratory symptoms (30 vs 72 days) and severity of illness. IFN-gamma levels were also higher.
How They Measured It
Incidence and duration of upper respiratory tract illness, IFN-gamma levels
To evaluate L. fermentum CECT5716 on incidence of respiratory and GI infections in infants.
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate L. fermentum CECT5716 on incidence of respiratory and GI infections in infants.
Dose
2 × 10^9 CFU/day
Participants
215 infants aged 1-6 months
Duration
6 months
Results
L. fermentum significantly reduced incidence of GI infections (35% reduction) and showed trend towards reduced respiratory infections.
How They Measured It
Incidence of respiratory and gastrointestinal infections
To assess L. fermentum on immune markers and vaccine response.
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To assess L. fermentum on immune markers and vaccine response.
Dose
10^9 CFU/day
Participants
60 healthy adults
Duration
4 weeks
Results
L. fermentum enhanced vaccine-specific IgA response and modulated cytokine profiles towards enhanced mucosal immunity.
How They Measured It
Vaccine-specific IgA and IgG, inflammatory cytokines
Gut Health
To evaluate L. fermentum on gut microbiome composition and intestinal health markers.
Study Type
Randomised controlled trial
Purpose
To evaluate L. fermentum on gut microbiome composition and intestinal health markers.
Dose
2 × 10^9 CFU/day
Participants
40 healthy volunteers
Duration
6 weeks
Results
L. fermentum increased fecal Lactobacillus and Bifidobacterium counts, elevated SCFA production (butyrate), and improved intestinal permeability.
How They Measured It
Fecal microbiome (16S rRNA), fecal SCFA levels, intestinal permeability
To assess L. fermentum for antibiotic-associated GI symptoms.
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To assess L. fermentum for antibiotic-associated GI symptoms.
Dose
10^9 CFU/day
Participants
78 H. pylori-positive patients
Duration
2 weeks antibiotic + 2 weeks follow-up
Results
L. fermentum significantly reduced incidence of antibiotic-associated GI symptoms (23% vs 48% placebo) and maintained higher fecal Lactobacillus counts.
How They Measured It
Incidence of GI symptoms (diarrhea, bloating, nausea), stool consistency
Cholesterol & Metabolic Health
To evaluate L. fermentum ME-3 on lipid profile and antioxidant status.
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate L. fermentum ME-3 on lipid profile and antioxidant status.
Dose
2 × 10^9 CFU/day
Participants
45 moderately hypercholesterolemic adults
Duration
4 weeks
Results
L. fermentum ME-3 significantly reduced total cholesterol, LDL-C, and oxidized LDL levels. Total antioxidant capacity increased significantly.
How They Measured It
Total cholesterol, LDL-C, HDL-C, oxidized LDL, total antioxidant capacity
To evaluate L. fermentum on metabolic parameters in overweight adults.
Study Type
Randomised controlled trial
Purpose
To evaluate L. fermentum on metabolic parameters in overweight adults.
Dose
2 × 10^9 CFU/day
Participants
52 overweight adults (BMI 25-30)
Duration
12 weeks
Results
L. fermentum group showed modest but significant reductions in total cholesterol and LDL-C. No significant effects on body weight or fasting glucose.
How They Measured It
Body weight, BMI, lipid profile, fasting glucose
Frequently Asked Questions
Common questions about Lactobacillus fermentum research
There are currently 7 peer-reviewed studies on Lactobacillus fermentum (Limosilactobacillus fermentum), involving 510 total participants. Research covers Immune support, Respiratory health, Gut health and 1 more areas. The overall evidence strength is rated as Very Strong.
The evidence is currently rated as "Very Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (7 human studies), and reported outcomes.
Lactobacillus fermentum has been researched for: Immune support, Respiratory health, Gut health, Cholesterol management. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 7 out of 7 studies are human trials. Human trials carry more weight in our evidence scoring system.
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