Currently submitted to: JMIR Research Protocols
Date Submitted: Sep 9, 2026
Open Peer Review Period: Sep 10, 2026 - Nov 5, 2026
(currently open for review)
Warning: This is an author submission that is not peer-reviewed or edited. Preprints - unless they show as "accepted" - should not be relied on to guide clinical practice or health-related behavior and should not be reported in news media as established information.
Faecal microbiota transplantation for improving insulin sensitivity in adults with type 2 diabetes mellitus (FeMIC): study protocol for a randomised controlled trial
ABSTRACT
Background:
Alterations in gut microbiota composition have been implicated in the pathogenesis of type 2 diabetes (T2DM), and faecal microbiota transplantation (FMT) has emerged as a microbiota-targeted intervention with potential metabolic effects. Randomised controlled trials evaluating the effects of FMT on insulin sensitivity in individuals with T2DM are limited.
Objective:
This study aims to investigate the effects of FMT on insulin sensitivity and glycaemic control in individuals with T2DM.
Methods:
This is a single-center, randomised, double-blind, placebo-controlled trial. Sixteen participants with T2DM have been randomised in a 1:1 ratio to receive FMT from two healthy donors or a placebo intervention, administered in two predefined procedures using capsules. Assessments were performed at baseline and after the intervention period. The primary outcome is insulin sensitivity, assessed using the Matsuda index derived from a standardised oral glucose tolerance test (OGTT) after six weeks. Secondary outcomes include dynamic insulin sensitivity assessed by the oral glucose insulin sensitivity index and detailed glycaemic profiling using continuous glucose monitoring (time-in-range, glycaemic variability), alongside anthropometry, circulating metabolic and inflammatory biomarkers, and gut microbiota composition and functional capacity. Outcomes will be analysed using analysis of covariance, adjusting for baseline values, and will follow the intention-to-treat principle.
Results:
As of June 2026, all 16 participants have been enrolled and completed all patient visits. Laboratory analyses for the primary outcomes are in progress and therefore no results are currently available.
Conclusions:
This randomised controlled trial will evaluate whether repeated FMT can improve insulin sensitivity in individuals with T2DM. The integration of dynamic OGTT-derived insulin sensitivity indices and continuous glucose monitoring–based glycaemic profiling enables a comprehensive assessment of glucose metabolism following microbiota modulation. Clinical Trial: ClinicalTrials.gov, study identifier NCT07375797, registered on 12 January 2026
Citation
Request queued. Please wait while the file is being generated. It may take some time.
Copyright
© The authors. All rights reserved. This is a privileged document currently under peer-review/community review (or an accepted/rejected manuscript). Authors have provided JMIR Publications with an exclusive license to publish this preprint on it's website for review and ahead-of-print citation purposes only. While the final peer-reviewed paper may be licensed under a cc-by license on publication, at this stage authors and publisher expressively prohibit redistribution of this draft paper other than for review purposes.