BACKGROUND: Functional dyspepsia is a common gastrointestinal condition that reduces the quality of life and increases health care costs. The lack of well-defined causes limits effective treatments. Consumers report using mānuka honey to treat gastrointestinal symptoms, although clinical evidence supporting such use is limited. Preclinical studies suggest its unique bioactive compounds may reduce gastrointestinal inflammation. Recently, 3,6,7-trimethyllumazine (Lepteridine), a natural pteridine in mānuka honey, was shown to inhibit enzymes involved in gastrointestinal inflammation in in vitro studies. Therefore, Lepteridine-standardized mānuka honey may deliver digestive health benefits. OBJECTIVE: The aim of this feasibility study is to gather the data required to estimate sample size and support study logistics to design future trials. The primary objective will be preliminary assessments of the impact of Lepteridine-standardized mānuka honey on symptom severity and the quality of life in participants with mild-to-moderate functional dyspepsia. Other feasibility objectives include assessing the biological responses to mānuka honey standardized to medium and high levels of Lepteridine and measuring mānuka honey-derived metabolites in blood and urine. METHODS: This is a 3-arm, parallel, controlled, double-blind, randomized feasibility study. A total of 75 healthy adults with symptoms of functional dyspepsia (Rome IV criteria) and mild-to-moderate dyspepsia severity (Short Form Leeds Dyspepsia Questionnaire) were recruited between October 2022 and September 2023. Participants were randomized into one of three groups: (1) mānuka honey standardized to contain 10 mg/kg Lepteridine, (2) mānuka honey standardized to contain 40 mg/kg Lepteridine, or (3) honey maple flavored syrup control. After a 2-week lead-in period, participants consumed 10 g of allocated intervention twice daily for 6 weeks. Throughout the study, participants completed daily bowel movement diaries and validated weekly questionnaires about their gastrointestinal symptoms and quality of life. Stool samples and 3-day diet records were collected at baseline and the end of the intervention. Blood samples were collected at baseline, weeks 2 and 4, and at the end of the intervention. In addition, 6 healthy participants without symptoms of functional dyspepsia were recruited to undergo an acute 5-hour assessment for the appearance of Lepteridine and related metabolites in plasma and urine following consumption of Lepteridine-standardized mānuka honey. The study was approved by the Northern B Health and Disability Ethics Committee. RESULTS: Initial analysis includes 68 participants, with laboratory and data analyses being undertaken as of March 2024. The results of the primary and secondary outcomes will be published in peer-reviewed journals. CONCLUSIONS: This study will provide essential information on the potential efficacy and suitability of Lepteridine-standardized mānuka honey for designing future clinical trials investigating its effect in treating symptoms of functional dyspepsia. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ANZCTR) ACTRN12622001140741p; https://anzctr.org.au/Trial/Registration/TrialReview.aspx?id=384094. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/66417.