The goal of this trial is to evaluate the safety and tolerability of an 8-week, multi-component nutritional supplement (AV1PD1A) in adults with hydrogen-dominant small intestinal bacterial overgrowth (SIBO).

The main questions the study aims to answer are:

1. Is the product safe and well-tolerated over 8 weeks, as measured by bloodwork, vital signs, and adverse effects?
2. How many participants adhere to the intervention without a dose modification, hold, or discontinuation?

Exploratory questions include: do GI symptoms and quality of life ratings improve, and do hydrogen/methane levels on lactulose breath testing change from baseline to week 8?

There is no comparison group; this is a prospective, open-label, single-arm pilot trial (n=10).

Participants will:

• Be screened and confirmed to have hydrogen-dominant SIBO by lactulose breath test (with 24-hour prep diet and overnight fast).
• Take AV1PD1A, three capsules daily for 8 weeks.
• Attend three clinic visits at baseline, week 4, and week 8 for vital measurements, fasting blood draws, and adverse event checks.
• Complete questionnaires on symptoms and quality of life.
• Repeat the lactulose breath test at week 8 to assess changes in hydrogen and methane.

Prospective, single-site, open-label, single-group pilot conducted at NUNM's Helfgott Research Institute (Portland, OR). The investigational product (AV1PD1A) is a multi-component dietary supplement containing Saccharomyces cerevisiae fermentate (EpiCor), N-acetyl-glucosamine, Saccharomyces boulardii, Lactobacillus rhamnosus (heat-killed), methylcobalamin, berberine, and gingerol (ginger extract). Dosing: 3 capsules daily for 8 weeks. Primary outcome is safety/tolerability (labs, vitals, AEs). Exploratory outcomes include validated PROMIS instruments, IBS Adequate Relief, and changes in lactulose breath-test hydrogen/methane. Enrollment is single-arm with anticipated n = 10 (pilot) to establish feasibility/tolerability signals that inform future powered trials.

Inclusion Criteria:

• Adults ≥ 18 years.
• Meets North American Consensus criteria for hydrogen-dominant SIBO by lactulose breath test.
• Willing to: take study supplement (3 caps/day for 8 weeks); complete two lactulose breath tests with required prep/fast; undergo three fasting blood draws; complete questionnaires.
• Able to provide informed consent and communicate in English.
• Individuals of child-bearing potential agree to use effective contraception during the study.

Exclusion Criteria:

• Recent antibiotics/antifungals/supplements that confound breath test results (e.g., antibiotics within 14 days before breath test; current systemic or topical antifungals).
• Recent changes in diet/medications/supplement regimen within 30 days.
• Hospitalization within past 3 months.
• Allergy/intolerance to product components (e.g., Saccharomyces, Lactobacillus, shellfish [for N-acetyl-glucosamine], ginger, or berberine).
• Renal/hepatic abnormalities at screening (e.g., eGFR <60 mL/min/1.73 m2; AST/ALT/bilirubin outside of normal reference ranges).
• Hepatitis from any cause; excessive alcohol use (>7 drinks/week women; > 14 drinks/week men).
• Medications with concerning interactions after clinical investigator review

Aggregate, de-identified results will be disseminated; IPD may be considered upon reasonable request and IRB/DUA approvals