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Head-to-head evidence comparison — which supplement is right for you?
Saccharomyces Boulardii vs Vitamin C: they're closely matched on evidence (8.5 vs 8/10); they're alternatives for support immune system — the best pick depends on your goals. Take the 60-second quiz for a pick tailored to your goals.
Saccharomyces Boulardii and Vitamin C are closely matched across evidence, studies, and safety.
Verdict
Likely helps
4 of 4 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
8 of 11 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (1)
Outcomes where both Saccharomyces Boulardii and Vitamin C have evidence — compare verdict strength side-by-side.
250-500mg (5-10 billion CFU) daily
With or without food, At least 2 hours away from antifungals
Capsules (lyophilized)
500-1000mg
With meals, Split doses if taking >500mg
Ascorbic acid or buffered vitamin C
During use
1-3 days
1-2 weeks
Ongoing
1-2 weeks
4-8 weeks
With high doses (>2g)
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.
Vitamin C supplementation for prevention and treatment of pneumonia.
The Cochrane database of systematic reviews (2021) · Systematic review · n=2655
Five studies with 2655 participants (2 RCTs, 3 quasi-RCTs). Three included children under five, one school-aged children and one adults.
Vitamin C supplementation in pregnancy
The Cochrane database of systematic reviews (2015) · Meta analysis · n=24300
29 trials involving 24,300 pregnant women.
Enhanced Vitamin C Delivery: A Systematic Literature Review Assessing the Efficacy and Safety of Alternative Supplement Forms in Healthy Adults
Nutrients (2025) · Systematic review
Most studies (77%) had a low risk of bias.
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 Saccharomyces Boulardii and Vitamin C are closely matched — the best choice depends on your specific health goals.
For support immune system, Vitamin C has a higher relevance score (85 vs 60).
No documented interaction was found in the data searched. This does not establish that this exact combination is safe.
AREDS2 works for diagnosed AMD; lutein/screen-strain claims are weaker. Who actually benefits.
CoQ10, zinc, selenium, carnitine modestly help sperm parameters — but live-birth evidence is weak.
Zinc timing, vitamin D, the real vitamin C effect — and the elderberry caution.
The right pick depends on your goals. Answer a few quick questions for a personalised recommendation — or dig into the full evidence on each.