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Head-to-head evidence comparison — which supplement is right for you?
Nicotinamide vs Saccharomyces Boulardii: they're closely matched on evidence (5.5 vs 8.5/10); they're alternatives for inflammation-related symptoms — the best pick depends on your goals. Take the 60-second quiz for a pick tailored to your goals.
Nicotinamide and Saccharomyces Boulardii are closely matched across evidence, studies, and safety.
Verdict
Too few graded studies
2 of 2 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
4 of 4 studies with measurable effects showed benefit.
Top outcomes
500mg twice daily
Morning and evening with meals
Niacinamide tablets (500mg)
250-500mg (5-10 billion CFU) daily
With or without food, At least 2 hours away from antifungals
Capsules (lyophilized)
3-12 months
8 weeks
Days
First days
During use
1-3 days
1-2 weeks
A Phase 3 Randomized Trial of Nicotinamide for Skin-Cancer Chemoprevention.
The New England journal of medicine (2015) · Rct · n=386
ONTRAC: phase-3, double-blind RCT randomizing 386 patients with ≥2 prior non-melanoma skin cancers to 500 mg nicotinamide twice daily or placebo for 12 months
Skin Cancer Prevention and Antiaging: Role of Nicotinamide.
International journal of molecular sciences (2026) · Review
Review of the biological rationale and clinical evidence for nicotinamide and NAD+ precursors in photoaging and cutaneous carcinogenesis
Topical nicotinamide compared with clindamycin gel in the treatment of inflammatory acne vulgaris.
International journal of dermatology (1995) · Rct · n=76
Double-blind RCT of 76 patients randomized to 4% nicotinamide gel or 1% clindamycin gel twice daily for 8 weeks for moderate inflammatory acne
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 Nicotinamide and Saccharomyces Boulardii are closely matched — the best choice depends on your specific health goals.
For inflammation-related symptoms, Nicotinamide has a higher relevance score (45 vs 40).
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.