Bacillus Subtilis
Useful mainly for people wanting a spore-based probiotic for digestive comfort.
Quick decision guide
May help most
people wanting a spore-based probiotic for digestive comfort
Common dosing range
1–10 billion CFU/day (strain-dependent)
When to expect effects
Weeks
Watch out for
avoid in severe immunocompromise (rare bacteremia risk)
What is it
Bacillus subtilis is a gram-positive, spore-forming probiotic bacterium used in supplements for gut and immune support; common strains include DE111, BS50, and HU58.
Is it worth it for you?
Use this as a quick fit check, not a diagnosis.
Worth considering if…
Probably skip if…
Evidence at a glance
| Goal | Effect | Best fit | Time |
|---|---|---|---|
gut comfort and bowel regularity Limited Evidence | Modest | adults with mild digestive discomfort or irregularity | Weeks |
immune function markers Limited Evidence | Uncertain | uncertain; explored in general adults | Weeks |
gut comfort and bowel regularity
- Effect
- Modest
- Best fit
- adults with mild digestive discomfort or irregularity
- Time
- Weeks
immune function markers
- Effect
- Uncertain
- Best fit
- uncertain; explored in general adults
- Time
- Weeks
Evidence for 2 uses
AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.
gut comfort and bowel regularity
Supplement benefitSpore-forming Bacillus subtilis survives gastric transit and, in strain-specific RCTs (e.g. DE111), has modestly improved bowel regularity and digestive comfort versus placebo. Effects are tied to the specific strain studied and are generally modest. Benefits do not automatically transfer to other strains.
Bottom line: Specific strains modestly improve GI comfort and regularity.
immune function markers
Biomarker supportSome strains germinate in the gut and engage innate immune signaling, and small studies report changes in immune markers. These are biomarker findings rather than demonstrated reductions in illness. Evidence is preliminary and strain-specific.
Bottom line: May shift some immune markers, but clinical immune benefit is unproven.
How it works
How to take it
What to track
1 commercial form
Compare the main delivery options and what they’re best suited for.
Spore probiotic capsule
Survives storage and gastric transit without refrigeration.
Heat- and acid-stable.
Safety
Know the common side effects, key cautions, and who should avoid it.
Common side effects
Serious risks
rare bacteremia in immunocompromised patients
Who should avoid it
- people with severe immunocompromise
- people with central venous catheters
- people with recent gut surgery (without clinician guidance)
Pregnancy & breastfeeding
Limited specific data; most strains are GRAS for food use—discuss with a clinician if pregnant.
Interactions
live organism may pose infection risk in immunocompromise
Food sources
| Food | Amount | %DV |
|---|---|---|
| Natto (fermented soybeans) | 1 oz | — |
Natto (fermented soybeans)
- Amount
- 1 oz
- %DV
- —
Choosing a product
What to look for on the label — and what to be skeptical of.
Look for…
Be skeptical of…
Frequently asked questions
Does Bacillus subtilis need refrigeration?⌄
No. Spore-forming probiotics are stable at room temperature.
References by claim
Track Bacillus Subtilis with Pilora
Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.
Coming to App StoreDisclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.