tuneTypical Dose
1 to 2 billion CFU once daily from a strain-disclosed product
Microbiome Modulator
Bacillus subtilis
Bacillus subtilis
Evidence TierCWADA NOT PROHIBITED
watchEffect Window
If Bacillus subtilis helps, the signal should usually become clear within 4 to 6 weeks rather than within a few days.
check_circleCompliance
WADA NOT PROHIBITED
Overview
Clinical Summary
Bacillus subtilis is a spore-forming probiotic with early human evidence for modest GI symptom support, but the data are still small, strain-specific, and mostly industry-linked.
Bacillus subtilis stands out from conventional probiotics because it is spore-forming. That makes it shelf-stable, resistant to stomach acid, and biologically plausible as an oral probiotic. Human trials show that specific strains can survive transit into the small intestine and may modestly improve gas-related or constipation-type symptoms over 4 to 6 weeks. The limitation is that the evidence base is still small, uses different proprietary strains and even different product formats, and does not justify broad claims about microbiome health, immunity, or treatment of GI disease.
Bacillus subtilis works mainly through spore-based delivery. The dormant spore survives gastric transit, reaches the small intestine, and germinates into a metabolically active vegetative cell. Potential downstream effects include mild modulation of GI ecology and immune signaling, but these clinical effects remain strain-specific and incompletely established.
Outcomes
What This Is Expected To Influence
Primary Outcomes
- Modest improvement in selected gas-related digestive symptoms
- Possible improvement in constipation-type symptoms in selected adults
Secondary Outcomes
- Direct human confirmation of small-intestinal survival and germination for DE111
- Exploratory immune-modulation signals without proven clinical immune benefit
Safety
Contraindications and Interactions
Contraindications
- Severe immunocompromise
- Critical illness or hospitalization
- Major intestinal barrier compromise
Side effects
- Mild gas or bloating
- Transient stool-pattern change
Interactions
- Systemic antibiotics
Avoid if
- You are severely immunocompromised without clinician guidance
- You are using an undisclosed or strain-ambiguous probiotic and expecting trial-backed effects
Evidence
Study-level References
bacsub-SRC-001Randomized controlled trial
Sourceopen_in_newGarvey 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. PMID:36269141.
Population: Healthy adults with baseline gas-related gastrointestinal complaints.
Dose protocol: 2 billion CFU/day for 6 weeks
Key findings: Increased the proportion of adults reporting improvement in a composite of bloating, burping, and flatulence.
Notes: Useful short-term symptom trial, but strain specific and industry linked.
Paper content
In healthy adults, six weeks of Bacillus subtilis BS50 at 2 billion CFU per day increased the proportion of participants reporting improvement in a composite of bloating, burping, and flatulence compared with placebo. The clearest individual symptom signal was for burping, with a favorable trend for bloating. Clinical chemistry, hematology, and gut-permeability or inflammatory markers did not meaningfully change, supporting short-term tolerability but not broader metabolic claims.
bacsub-SRC-002Randomized controlled trial
Sourceopen_in_newPatch C, Pearce AJ, Cheng M, Boyapati R, Brenna JT. Bacillus subtilis (BG01-4) improves self-reported symptoms for constipation, indigestion, and dyspepsia. A phase 1/2A randomized controlled trial. Nutrients. 2023;15(21):4490. doi:10.3390/nu15214490. PMID:37960143.
Population: Adults with self-reported functional gastrointestinal disorder symptoms.
Dose protocol: 4-week proprietary BG01-4 protocol
Key findings: Showed the clearest signal for constipation-related symptom improvement, with weaker support for indigestion and dyspepsia.
Notes: Supports narrow GI symptom framing rather than broad digestive claims.
Paper content
This four-week phase 1/2A randomized trial tested a proprietary Bacillus subtilis BG01-4 preparation in adults with self-reported functional GI complaints. The strongest prespecified signal was for constipation, while exploratory analyses also favored the active product for indigestion and dyspepsia clusters. Because several endpoints improved in both groups and the intervention used a deactivated proprietary preparation, the study supports only a narrow, formulation-specific GI symptom signal rather than broad claims for Bacillus subtilis generally.
bacsub-SRC-003Randomized, crossover, double-blind, placebo-controlled study
Sourceopen_in_newColom J et al. 2021. Presence and Germination of the Probiotic Bacillus subtilis DE111 in the Human Small Intestinal Tract. Frontiers in Microbiology. 12:715863.
Population: Adults with ileostomy allowing direct sampling of small intestinal effluent
Dose protocol: Single 5 billion CFU dose in ileostomy crossover sampling
Key findings: Confirmed survival and germination of DE111 spores in the human small intestine.
Notes: Important mechanistic study, not a symptom-efficacy trial.
Paper content
This crossover study in 11 ileostomy participants provided direct human evidence that orally ingested B. subtilis DE111 spores survive gastric transit and germinate in the human small intestine within 3 hours of ingestion. Spore counts rose substantially by 6 hours and vegetative cells peaked at 7 hours, confirming that the spore-forming probiotic transitions from dormant spore to metabolically active vegetative form in the relevant gut compartment. This is important mechanistic evidence supporting the biological plausibility of B. subtilis as a probiotic, as it demonstrates the organism actually reaches and activates in the target tissue rather than simply passing through inert.
bacsub-SRC-004Randomized, double-blind, placebo-controlled pilot trial
Sourceopen_in_newTrotter RE et al. 2021. Examining the Gastrointestinal and Immunomodulatory Effects of the Novel Probiotic Bacillus subtilis DE111. Nutrients. 13(11):3889.
Population: Healthy adults aged 18-65
Dose protocol: 1 billion CFU/day for 4 weeks
Key findings: Did not improve global GI-health measures, though exploratory immune assays suggested anti-inflammatory signaling.
Notes: Important reason to keep overall claims narrow.
Paper content
Pilot RCT in 76 healthy adults found that 4 weeks of B. subtilis DE111 (1 billion CFU/day) did not significantly change self-reported GI health, fecal microbiota, or circulating inflammatory markers. However, ex vivo PBMC stimulation with LPS revealed increased anti-inflammatory immune cell populations in the DE111 group, suggesting potential immunomodulatory activity that would require a larger, adequately powered trial to confirm. The study was likely underpowered for its primary GI endpoints.
bacsub-SRC-005Randomized, double-blind, placebo-controlled trial
Sourceopen_in_newToohey JC et al. 2018. Effects of Probiotic (Bacillus subtilis DE111) Supplementation on Immune Function, Hormonal Status, and Physical Performance in Division I Baseball Players. Sports. 6(3):70.
Population: Division I male baseball athletes during 12 weeks of offseason training
Dose protocol: 1 billion CFU/day for 12 weeks in athletes
Key findings: Suggested possible anti-inflammatory effects during training stress without clear performance benefit.
Notes: Secondary support only, not a core digestive-efficacy trial.
Paper content
This 12-week RCT in 25 Division I male baseball athletes examined whether daily B. subtilis DE111 (1 billion CFU) affected immune markers, hormonal status, and performance during offseason training. TNF-alpha was maintained in the probiotic group while it increased in the placebo group, suggesting a potential anti-inflammatory effect. Testosterone, cortisol, and mucosal immune markers (SIgA, SIgM) did not differ significantly between groups. The study was small and exploratory, but demonstrated safety and tolerability of DE111 in a young athletic population under training stress. The results provide preliminary support for immune-related benefits but are insufficient alone to confirm efficacy.
bacsub-SRC-006Randomized, placebo-controlled trial.
Sourceopen_in_newPaytuvi-Gallart A, Sanseverino W, Winger AM. Daily intake of probiotic strain Bacillus subtilis DE111 supports a healthy microbiome in children attending day-care. Benef Microbes. 2020;11(7):611-620. doi:10.3920/BM2020.0022. PMID:33161736.
Population: Healthy children aged 2 to 6 years attending day care.
Dose protocol: Once-daily DE111 versus placebo for 8 weeks in healthy children aged 2 to 6 years attending day care.
Key findings: Increased alpha diversity and lowered the Firmicutes/Bacteroidetes ratio, with several directionally anti-inflammatory taxonomic shifts.
Notes: Supports biologic activity and subtle microbiome effects, but in a pediatric population and without a direct symptom endpoint.
Paper content
This pediatric randomized placebo-controlled trial tested once-daily Bacillus subtilis DE111 for 8 weeks in healthy children attending day care. The study did not show a between-group shift in overall microbiome equilibrium, but it did find increased alpha diversity from baseline within the probiotic group, a lower Firmicutes/Bacteroidetes ratio, and differential abundance changes in several taxa linked to lower inflammatory tone. The paper is useful as a human signal that DE111 can produce subtle microbiome shifts in a real-world population, but it remains a microbiome-marker study rather than direct evidence for a clinical digestive or immune endpoint.
bacsub-SRC-007Randomized, double-blind, placebo-controlled 4-week intervention.
Sourceopen_in_newTrotter RE, Vazquez AR, Grubb DS, et al. Bacillus subtilis DE111 intake may improve blood lipids and endothelial function in healthy adults. Benef Microbes. 2020;11(7):621-630. doi:10.3920/BM2020.0039. PMID:33161737.
Population: Healthy adults aged 18 to 65 years with BMI 20.0 to 34.9.
Dose protocol: DE111 versus maltodextrin placebo for 4 weeks in healthy adults.
Key findings: Reduced total cholesterol and non-HDL cholesterol from baseline, with a trend toward improved endothelial function.
Notes: Exploratory cardiometabolic signal only. Useful for modernizing the mechanistic picture, not for turning Bacillus subtilis into a lipid supplement.
Paper content
This randomized double-blind placebo-controlled adult study followed Bacillus subtilis DE111 for 4 weeks and looked at exploratory cardiovascular markers rather than GI symptoms. The probiotic arm showed significant reductions in total cholesterol and non-HDL cholesterol relative to baseline, with a trend toward improved endothelial function and LDL cholesterol. These findings are interesting because they suggest the strain may have broader metabolic activity in humans, but the population was largely healthy and the study was not a definitive cardiometabolic outcomes trial. For supplement catalog purposes, the study is best used as exploratory modern evidence rather than as a basis for strong cholesterol-lowering claims.
bacsub-SRC-008Randomized, double-blind, placebo-controlled acute mechanistic study.
Sourceopen_in_newColom J, Freitas D, Simon A, et al. Acute physiological effects following Bacillus subtilis DE111 oral ingestion - a randomised, double blinded, placebo-controlled study. Benef Microbes. 2023;14(1):31-44. doi:10.3920/BM2022.0081. PMID:36790091.
Population: Human ileostomy model participants sampled after acute oral ingestion.
Dose protocol: Acute randomized double-blind placebo-controlled DE111 ingestion with ileostomy sampling over hours after dosing.
Key findings: Extended the prior germination work by showing early metabolomic and proteomic shifts linked to digestion, antimicrobial activity, and lipid handling.
Notes: Strong mechanistic follow-up study. It adds depth to the biologic story without changing the narrow efficacy framing.
Paper content
This acute randomized double-blind placebo-controlled DE111 study used ileostomy sampling to measure early physiologic changes within hours of ingestion. Beyond confirming the organism's presence, it reported shifts in metabolomic and proteomic markers tied to digestion, lipid handling, antimicrobial activity, and mucosal immune signaling. The study is useful because it modernizes the mechanistic picture from simple survival/germination to a broader early-response signature. It still does not establish durable clinical benefit, so it should be used to refine biologic plausibility rather than to justify strong digestive, immune, or metabolic efficacy claims.
bacsub-SRC-009Randomized, double-blind, placebo-controlled trial
Sourceopen_in_newLeMoire A, Lin L, Girard SA, Baisley J, Wang J, Atif A, Zahra R, Millette M. Effect of Bacillus subtilis ATCC 122264 on intestinal gas symptoms and quality of life in adults with functional bloating. Benef Microbes. 2025;16(3):281-292. doi:10.1163/18762891-bja00057. PMID:39929203.
Population: Healthy adults with functional bloating per ROME IV criteria.
Dose protocol: B. subtilis ATCC 122264 at 5 billion CFU daily for 8 weeks in 100 adults with ROME IV functional bloating.
Key findings: Primary endpoint (IGQ global score) did not differ from placebo overall. Female subgroup showed significant improvements in belching (P = 0.046) and flatulence severity (P = 0.039) and functional impact (P = 0.03).
Notes: Adds a new strain to the evidence base and highlights potential sex-specific effects. The null primary endpoint keeps overall claims narrow.
Paper content
This 8-week RCT tested Bacillus subtilis ATCC 122264 at 5 billion CFU daily in 100 adults with ROME IV functional bloating. The primary endpoint (IGQ global score) did not differ from placebo in the overall population. However, female participants showed significant improvements in belching severity at 4 weeks (P = 0.046) and flatulence severity (P = 0.039) and functional impact (P = 0.03) at 8 weeks. The strain was safe and well tolerated.
bacsub-SRC-010Randomized, double-blind, placebo-controlled trial
Sourceopen_in_newSorensen K, Jog P, Mankar S, Holz C, Jadhav S. Effects of spore-forming probiotic Bacillus subtilis HU58 in children with antibiotic-associated diarrhoea: a randomised, double-blind, placebo-controlled trial. Benef Microbes. 2025;17(1):1-10. doi:10.1163/18762891-bja00086. PMID:40716758.
Population: Children aged 1 to 12 years with antibiotic-associated diarrhea.
Dose protocol: B. subtilis HU58 at 2 billion CFU daily for 7 days in 68 children with antibiotic-associated diarrhea.
Key findings: 93.5% diarrhea resolution at Day 3 vs 22.6% for placebo (P < 0.001). Abdominal pain and GI wellbeing also significantly improved.
Notes: Pediatric AAD population and short duration limit generalization to adult chronic use, but the effect size is large. Industry-linked (Novozymes).
Paper content
This RCT tested Bacillus subtilis HU58 at 2 billion CFU daily in 68 children with antibiotic-associated diarrhea. By Day 3, 93.5% of probiotic recipients had normal stools versus 22.6% on placebo (P < 0.001). Abdominal pain scores dropped substantially more in the probiotic group (P < 0.001), and GI wellbeing measures improved significantly at Days 3 and 7. The effect size is notable, though the pediatric population and short duration limit generalization to adults.