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Head-to-head evidence comparison — which supplement is right for you?
L-Glutamine vs Saccharomyces Boulardii: they're closely matched on evidence (6 vs 8.5/10); they're alternatives for improve digestion — the best pick depends on your goals. Take the 60-second quiz for a pick tailored to your goals.
L-Glutamine and Saccharomyces Boulardii are closely matched across evidence, studies, and safety.
Verdict
Too few graded studies
1 of 1 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
4 of 4 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (2)
Outcomes where both L-Glutamine and Saccharomyces Boulardii have evidence — compare verdict strength side-by-side.
5-10g (a typical label dose, not the dose used in the cited trials, which dosed by body weight at 0.3 to 0.6 g per kg a day)
Post-workout, Before bed, Or split throughout day
L-Glutamine powder
250-500mg (5-10 billion CFU) daily
With or without food, At least 2 hours away from antifungals
Capsules (lyophilized)
Ongoing
2-4 weeks
2-4 weeks
During use
1-3 days
1-2 weeks
A Phase 3 Trial of l-Glutamine in Sickle Cell Disease
The New England journal of medicine (2018) · Rct · n=230
A total of 230 patients (age range, 5 to 58 years; 53.9% female) were randomly assigned, in a 2:1 ratio, to receive l-glutamine (152 patients) or placebo (78 patients).
What Is the Role of Nutritional Supplements in Support of Total Hip Replacement and Total Knee Replacement Surgeries? A Systematic Review
Nutrients (2018) · Systematic review
Amino acid supplementation is reported to reduce muscle atrophy and accelerate return of functional mobility.
Evidence and gaps in clinical outcomes of novel pharmacologic therapies for sickle cell disease: A systematic literature review highlighting insights from clinical trials and real-world studies
Blood reviews (2025) · Systematic review · n=97
A pivotal phase III study of l-glutamine showed that patients treated with l-glutamine had a 25 % reduction in pain crises and 33 % fewer hospital days compared to placebo. l-glutamine was generally well tolerated with minimal side effects.
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.
Both L-Glutamine and Saccharomyces Boulardii are closely matched — the best choice depends on your specific health goals.
For improve digestion, L-Glutamine has a higher relevance score (80 vs 70).
No documented interaction was found in the data searched. This does not establish that this exact combination is safe.
The right pick depends on your goals. Answer a few quick questions for a personalised recommendation — or dig into the full evidence on each.