Probiotics

Also known as: lactobacillus, bifidobacterium, probiotic blend, Saccharomyces boulardii

Grade B — Moderate Evidencemicrobiomegut

Recommended Dosage

10–50 billion CFU

With or just before a meal. If on antibiotics: 2+ hours away from dose.

Probiotics are live microorganisms that confer health benefits when consumed in adequate amounts. The gut microbiome is now recognized as a key regulator of immune function, metabolism, mood (via the gut-brain axis), and even cognitive function. Not all probiotics are equal — benefits are strain-specific, meaning a Lactobacillus rhamnosus GG has different effects than Lactobacillus acidophilus. Choosing the right strain for your specific goal is essential.

TL;DR: Beneficial bacteria for gut health. Strain selection matters — L. rhamnosus GG, B. infantis 35624, and S. boulardii are best-studied.

🦠Gut Health🛡️Immunity😊Mood
Last reviewed: 2026-03-09

Evidence Rating: Grade B — Moderate Evidence

Some RCTs with positive results, or strong observational evidence. More research may refine our understanding.

Forms Comparison

Lactobacillus/Bifidobacterium Blends

~ Moderate Absorption

The most studied probiotic genera. Look for specific strains (e.g., LGG, BB-12) with clinical evidence.

general gut healthantibiotic recoveryIBS

Saccharomyces boulardii

✓ High Absorption

A beneficial yeast, not a bacteria. Survives antibiotics and is specifically studied for diarrhea prevention.

antibiotic-associated diarrheaC. difftravel

Spore-Based (Bacillus)

✓ High Absorption

Spore-forming bacteria that survive stomach acid well. Growing evidence base.

shelf stabilitysurvival through stomach acid

Soil-Based Organisms (SBO)

~ Moderate Absorption

Organisms naturally found in soil. Less clinical evidence but theoretically mirrors ancestral exposure.

diversityancestral health approach

Interaction Warnings

ImmunosuppressantsModerate

Live bacteria may pose risk in immunocompromised individuals

AntifungalsModerate

Antifungals kill S. boulardii — do not combine

AntibioticsLow

Antibiotics may reduce probiotic effectiveness. Separate by 2+ hours.

⚠️ Important Notes

  • Strain-specific benefits — not all probiotics are equal
  • Start slowly to avoid bloating
  • Immunocompromised: consult physician

Clinical Evidence (3 studies)

Probiotics for antibiotic-associated diarrhea

Hempel S et al. (2012) — JAMA

Significantly reduced antibiotic-associated diarrhea risk

View on PubMed

L. rhamnosus GG for C. diff prevention

Szajewska H et al. (2007) — J Pediatr

Meta-analysis: L. rhamnosus GG prevents AAD

View on PubMed

B. infantis 35624 for IBS

O'Mahony L et al. (2005) — Gastroenterology

Normalized cytokine ratio in IBS patients

View on PubMed

Related Supplements

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Grade B — Moderate Evidence

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Glutamine

Grade B — Moderate Evidence

Conditionally essential amino acid that is the primary fuel for gut lining cells. RCT evidence for IBS and leaky gut.

Ginger

Grade A — Strong Evidence

Excellent evidence for anti-nausea effects (pregnancy, chemotherapy, post-op). Also anti-inflammatory with COX-2 inhibition.

Vitamin D3

Grade A — Strong Evidence

Essential hormone precursor. Most people in northern latitudes are deficient. Strong evidence for immunity, bone health, and mood.

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⚕️ Important Disclaimer

This information is for educational purposes only. It is not medical advice. Always consult a healthcare provider before starting any supplement regimen, especially if you take medications or have health conditions.

Evidence Stack does not sell supplements and has no affiliate relationships with supplement manufacturers.