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Head-to-head evidence comparison — which supplement is right for you?
L. rhamnosus GG vs Saccharomyces Boulardii: Saccharomyces Boulardii has the stronger overall evidence (8.5 vs 6/10); they work on different things and are often used together, not either/or. Take the 60-second quiz for a pick tailored to your goals.
Saccharomyces Boulardii wins 2 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Mostly mechanism / observational
Top outcomes
Verdict
Likely helps
4 of 4 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (2)
Outcomes where both L. rhamnosus GG and Saccharomyces Boulardii have evidence — compare verdict strength side-by-side.
10-20 billion CFU (1-2 x 10^10) daily. A meta-analysis in children with acute gastroenteritis found LGG effective at 10 billion CFU/day or more, and borderline below that.
Any time of day
Capsule standardized to ATCC 53103
250-500mg (5-10 billion CFU) daily
With or without food, At least 2 hours away from antifungals
Capsules (lyophilized)
Two independently evidenced routes to the same outcome, with non-overlapping vulnerability to antibiotics.
A defensible pairing during a course of antibiotics. The same immunocompromise and central-line cautions apply to both as live organisms.
During the antibiotic course
During hospital stay
n/a
n/a
During use
1-3 days
1-2 weeks
Lactobacillus rhamnosus GG versus Placebo for Acute Gastroenteritis in Children.
N Engl J Med (2018) · Rct · n=971
Primary outcome (modified Vesikari score >=9 within 14 days): 11.8% with LGG vs 12.6% placebo; RR 0.96 (0.68-1.35), P=0.83
Systematic review with meta-analysis: Lactobacillus rhamnosus GG in the prevention of antibiotic-associated diarrhoea in children and adults.
Aliment Pharmacol Ther (2015) · Meta analysis
Antibiotic-associated diarrhea fell from 22.4% to 12.3%; RR 0.49 (0.29-0.83) pooled across 11 RCTs, n=1,308 (12 RCTs, n=1,499 included overall)
Probiotics for treating acute infectious diarrhoea.
Cochrane Database Syst Rev (2020) · Meta analysis
In studies at low risk of bias, no difference in diarrhea lasting >=48 hours (RR 1.00, 0.91-1.09; moderate certainty)
Efficacy and safety of Saccharomyces boulardii as an adjuvant therapy for the eradication of Helicobacter pylori: a meta-analysis
Frontiers in cellular and infection microbiology (2025) · Meta analysis · n=5036
Meta-analysis of 19 studies with 5,036 people with H. pylori infection, adding S. boulardii to standard eradication therapy.
Probiotics for treating acute infectious diarrhoea
The Cochrane database of systematic reviews (2020) · Meta analysis · n=12127
Effect size was similar in the sensitivity analysis and marked heterogeneity persisted.
The use of probiotics and prebiotics in decolonizing pathogenic bacteria from the gut; a systematic review and meta-analysis of clinical outcomes
Gut microbes (2024) · Meta analysis · n=2871
This review aims to analyze available evidence from human-controlled trials to determine the effect size of probiotic interventions in decolonizing AMR pathogenic bacteria from the gut.
Both points come from a meta-analysis of 10 randomised trials adding S. boulardii to bismuth quadruple therapy (PMID 40251486), whose dose subgroups found the same gain in eradication at 500 mg a day (RR 1.10, 95% CI 1.03 to 1.17) and 1000 mg a day (RR 1.08, 95% CI 1.03 to 1.12). Effectiveness is the relative gain in eradication in percent. Total adverse effects fell with S. boulardii (RR 0.53), so the side effect values are low. The authors recommend 500 mg a day for more than 10 days. The effect is as an add-on to antibiotics only, and doses are in mg of product, not CFU.
AI-estimated from published studies. Interpret as directional guidance.
Saccharomyces Boulardii has a higher evidence score (8.5/10 vs 6/10) and wins in 2 of 3 categories.
For improve digestion, L. rhamnosus GG has a higher relevance score (72 vs 70).
L. rhamnosus GG and Saccharomyces Boulardii may work well together: Two independently evidenced routes to the same outcome, with non-overlapping vulnerability to antibiotics. A defensible pairing during a course of antibiotics. The same immunocompromise and central-line cautions apply to both as live organisms.
The right pick depends on your goals. Answer a few quick questions for a personalised recommendation — or dig into the full evidence on each.