Home Ingredients OPTIBIOME® BS50 (Bacillus subtilis Spore Probiotic — BIO-CAT)
Gut Health

OPTIBIOME® BS50 (Bacillus subtilis Spore Probiotic — BIO-CAT)

Evidence Level
Limited
3 Clinical Trials
2 Documented Benefits
2/5 Evidence Score

OPTIBIOME® BS50 is BIO-CAT's spore-forming Bacillus subtilis BS50 probiotic strain, clinically tested for gastrointestinal symptom reduction in healthy adults. Spore-forming probiotics offer practical advantages over standard probiotics: heat tolerance during manufacturing, survivability when exposed to oxygen, and stability without refrigeration. A published RCT documented decreased GI symptoms in healthy adults, and a preclinical safety assessment has also been published. Produced in BIO-CAT's fully-integrated U.S. fermentation facility in Minnesota.

Studied Dose 2x10^9 CFU/day (dose used in the Garvey 2022 RCT).
Active Compound Bacillus subtilis BS50, a spore-forming probiotic strain.

Benefits

Decreased gastrointestinal symptoms in healthy adults

A published clinical trial demonstrated Bacillus subtilis BS50 decreased gastrointestinal symptoms in healthy adults vs placebo. A national GI survey found a majority of community-dwelling adults reported at least one of eight specific GI symptoms over the prior week — making BS50's applications relevant to large adult populations.

Supported by Trial 1, Trial 2

Improvement in gas-related GI symptoms (burping, flatulence, bloating)

In the 6-week RCT (Garvey 2022), more BS50 participants than placebo showed improvement in a composite score of bloating, burping, and flatulence (47.4% vs 22.2%; OR 3.2, 95% CI 1.1-8.7, p=0.024). Among individual symptoms, burping improved significantly (44.7% vs 22.2%, p=0.041), while bloating showed a non-significant trend (31.6% vs 13.9%, p=0.071); other symptoms were unaffected.

Supported by Trial 1

Mechanism of action

1

Spore-form delivery and germination

Bacillus subtilis BS50 is delivered as endospores — dormant metabolically-inactive cells with thick protective coats. Spores germinate in the small intestine when exposed to appropriate signals (bile acids, amino acids). Germinated cells become metabolically active and produce probiotic effects. The spore-form delivery solves the survival problem common to traditional probiotics.

2

Enzyme and metabolite secretion

Bacillus subtilis produces multiple enzymes (proteases, amylases, cellulases) and bioactive metabolites. The secreted compounds may support digestion, modulate gut microbiome, and produce immunomodulatory effects. BS50 specifically has been characterized for its enzyme production profile distinct from other Bacillus subtilis strains.

3

Gut microbiome modulation

Probiotic Bacillus subtilis modulates the gut microbiome — supporting beneficial bacteria and competing with harmful microbes. Mechanism may involve direct antimicrobial metabolite production, niche competition for nutrients and binding sites, and host immune system modulation. The combined effects support overall gut health.

4

Gut-brain axis communication

Probiotic effects extend beyond direct GI symptoms via gut-brain axis communication. The gut microbiome influences systemic inflammation, immune function, and even cognitive and mood outcomes. While BS50's primary clinical evidence is GI symptom reduction, broader healthspan applications represent future research opportunities.

5

Spore stability vs vegetative bacteria

Vegetative bacterial cells are fragile — sensitive to heat, oxygen, gastric acid, and time. Spores are essentially indestructible — surviving boiling water, oxygen exposure, and years of room-temperature storage. The stability advantage means BS50 reaches the intestine alive in higher numbers vs traditional vegetative probiotics that may have minimal viability after manufacturing and storage.

Clinical trials

1
OPTIBIOME BS50 Healthy Adults GI Symptom Trial
PubMed

Randomized double-blind placebo-controlled clinical trial evaluating Bacillus subtilis BS50 for gastrointestinal symptoms in healthy adults. Outcomes via Gastrointestinal Symptom Rating Scale (GSRS), Gastrointestinal Tolerance Questionnaire (GITQ), Bristol Stool Scale, bowel habits diary. Published in Gut Microbes (Garvey et al.).

Healthy adults experiencing common GI symptoms (e.g., bloating, gas, burping). Randomized double-blind placebo-controlled design.

Bacillus subtilis BS50 decreased gastrointestinal symptoms in healthy adults vs placebo. Symptoms examined included common complaints like burping and bloating. In this single 76-adult trial funded by the maker, the gas-symptom composite improved modestly versus placebo. One small industry-funded trial is early evidence, not broad clinical validation.

2
BS50 Preclinical Safety Assessment (in silico genome screen and Caco-2 cell culture, not a human trial)
PubMed

Comprehensive preclinical safety assessment of Bacillus subtilis BS50 for probiotic and food applications. Published in Microorganisms (Brutscher, Borgmeier, Garvey, Spears). Foundation for the human clinical trials and regulatory applications.

Not applicable — comprehensive preclinical safety assessment including genomic, antibiotic resistance, virulence factor, and toxicology evaluations.

BS50 demonstrated safety profile suitable for probiotic and food applications. Genomic analysis confirmed absence of significant antibiotic resistance genes and virulence factors. Safety established the foundation for human clinical trial progression and commercial use. Supports long-term consumer use applications.

3
Bacillus subtilis Class Evidence (general category background, not a specific BS50 study)

Class evidence for Bacillus subtilis probiotics. Multiple trials of various B. subtilis strains for GI health, immune function, and broader health applications. Bacillus subtilis has extensive food-application history including in Japanese natto fermentation.

Various — adults across multiple Bacillus subtilis probiotic clinical trials.

Bacillus subtilis probiotics consistently demonstrate gastrointestinal symptom improvement, immune modulation, and good safety profile across multiple strains and trials. Strain-specificity matters — BS50 has been characterized specifically for its unique enzyme production and clinical effects. Class evidence supports the broader spore-forming probiotic category.

Side effects and drug interactions

Common Potential side effects

Generally well-tolerated; comprehensive preclinical safety assessment published.
Mild GI effects rare; some initial increase in gas as gut microbiome adjusts.
Spore form supports shelf-stable storage without refrigeration.
Long-term safety supported by extensive use of Bacillus subtilis in food applications (Japanese natto fermentation).
Immunocompromised individuals — caution with all live probiotics; consult clinician before use.
Pregnancy and lactation: generally considered safe; consult clinician.
Spore-forming probiotics generally have better survival rates than vegetative probiotics.

Important Drug interactions

Antibiotics — may reduce BS50 viability; separate dosing by 2+ hours if combining.
Immunosuppressants — caution with all probiotics; consult prescriber.
Other probiotics — generally complementary; combinations support broader microbiome support.
Prebiotic fibers (inulin, FOS) — complementary; support probiotic effects.
Fructanase enzymes — complementary; may stack for broader gut health.
Pregnancy and lactation: consult clinician.
Immunocompromised states (HIV, chemotherapy, transplant) — consult clinician before use.

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Frequently asked questions about OPTIBIOME® BS50 (Bacillus subtilis Spore Probiotic — BIO-CAT)

What is OPTIBIOME BS50?

Optibiome® BS50 is BIO-CAT's spore-forming Bacillus subtilis BS50 probiotic strain, clinically tested for gastrointestinal symptom reduction in healthy adults. Spore-forming probiotics offer practical advantages over standard probiotics: heat tolerance during manufacturing, survivability when exposed to oxygen, and sta…

What is OPTIBIOME BS50 used for?

OPTIBIOME BS50 is researched primarily for Gut Health. A published clinical trial demonstrated Bacillus subtilis BS50 decreased gastrointestinal symptoms in healthy adults vs placebo.

What is the recommended dosage of OPTIBIOME BS50?

The clinically studied dose is 2x10^9 CFU/day (dose used in the Garvey 2022 RCT). Always follow the product label and check with a healthcare provider for personal advice.

Is OPTIBIOME BS50 safe, and does it have side effects?

For most healthy adults, OPTIBIOME BS50 is well tolerated at studied doses. Reported effects can include: Generally well-tolerated; comprehensive preclinical safety assessment published. Mild GI effects rare; some initial increase in gas as gut microbiome adjusts. It may also interact with some medications. OPTIBIOME BS50 is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does OPTIBIOME BS50 interact with any medications?

Possible interactions include: Antibiotics — may reduce BS50 viability; separate dosing by 2+ hours if combining. Immunosuppressants — caution with all probiotics; consult prescriber. If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for OPTIBIOME BS50?

NutraSmarts rates the evidence for OPTIBIOME BS50 as Limited (2 out of 5). It is backed by 3 clinical trials and 2 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(2 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Garvey SM, Mah E, Blonquist TM, Kaden VN, Spears JL The probiotic Bacillus subtilis BS50 decreases gastrointestinal symptoms in healthy adults: a randomized, double-blind, placebo-controlled trial Gut Microbes. 2022;14(1):2122668. doi: 10.1080/19490976.2022.2122668.PubMedUsed to support: Industry-funded 6-week randomized, double-blind, placebo-controlled trial in 76 healthy adults (sponsored and manufactured by BIO-CAT, the maker of the strain). At 2x10^9 CFU/day, more BS50 than placebo improved a composite of bloating, burping and flatulence (47.4% vs 22.2%, OR 3.2, 95% CI 1.1-8.7, p=0.024) and burping alone (44.7% vs 22.2%, p=0.041). Bloating was only a non-significant trend (31.6% vs 13.9%, p=0.071) and other GI symptoms, blood lipids, and inflammation markers were unaffected.
  2. Brutscher LM, Borgmeier C, Garvey SM, Spears JL Preclinical Safety Assessment of Bacillus subtilis BS50 for Probiotic and Food Applications Microorganisms. 2022;10(5):1038. doi: 10.3390/microorganisms10051038.PubMedUsed to support: Preclinical safety assessment of BS50 using genome screening and human intestinal (Caco-2) cell culture, not a study in people. It found no known Bacillus toxin genes, susceptibility to seven of eight tested antibiotics, no transferable antibiotic-resistance elements, and no loss of intestinal cell viability or permeability. It supports safety only; it does not measure any GI benefit, oxygen tolerance, or shelf stability.