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Limited evidenceGut health

Bacillus Subtilis

A soil-derived spore probiotic, usually sold as DE111. It demonstrably survives and germinates in the small intestine, but the clinical trials behind it are small and mostly report surrogate outcomes.

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What the science says

  • Survival and germination in the gut Moderate evidence

    A randomized, crossover, double-blind, placebo-controlled study using intestinal sampling showed that B. subtilis DE111 spores reach the small intestine and germinate there. This establishes plausibility, not clinical benefit.

  • Bowel habit and immune markers Limited evidence

    A randomized study of DE111 in healthy adults found small changes in stool consistency and immune measures, without convincing symptomatic benefit.

  • Blood lipids and endothelial function Limited evidence

    A small randomized study reported that DE111 intake may improve blood lipids and endothelial function in healthy adults; the authors themselves frame it as preliminary.

Dosage & safety

Studied doseTrials used about 1 billion CFU per day of DE111. Products range from 1–5 billion CFU.
SafetyGenerally well tolerated in trials. Bacillus species are opportunistic pathogens in rare cases: avoid in severe immunosuppression, critical illness or with central venous catheters. Spore probiotics are sometimes blamed for bloating in people with SIBO, though this is not well studied.

How to take it

TimingTiming does not matter.
With food?Either way, since the spore coat survives stomach acid.
Worth knowingIf bloating gets worse rather than better over two weeks, spore probiotics are worth stopping rather than persisting with.

Interactions

With medications

  • antibiotics

    Antibiotics can kill the germinated bacteria, though spores are more robust than most probiotics. separate by at least 2 hours

  • immunosuppressants and chemotherapy

    Bacillus species are rare opportunistic pathogens and have caused infections in severely immunocompromised patients and those with central lines. do not start without medical advice

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Does Bacillus subtilis DE111 work?

B. subtilis DE111 spores demonstrably reach and germinate in the small intestine, but clinical trials are small and mostly report surrogate outcomes, so the evidence for real benefit is limited.

How much Bacillus subtilis per day?

Trials used about 1 billion CFU per day of B. subtilis DE111, and products range from 1–5 billion CFU.

Is Bacillus subtilis safe?

B. subtilis was generally well tolerated in trials, but Bacillus species are rare opportunistic pathogens, so avoid it in severe immunosuppression, critical illness or with central venous catheters. If bloating worsens over two weeks, stop rather than persist.

Scientific references

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