METFORMIN’S IMPACT ON BODY WEIGHT IN TYPE 2 DIABETES: A NARRATIVE REVIEW OF MECHANISMS, CLINICAL EVIDENCE, AND COMPARATIVE EFFICACY
DOI:
https://doi.org/10.31435/ijitss.3(51).2026.6514Keywords:
Metformin, Body Weight, Weight Loss, Type 2 Diabetes, GLP-1 Receptor Agonists, SGLT-2 InhibitorsAbstract
Background: Metformin remains one of the most widely prescribed first-line therapies for type 2 diabetes, yet its role as a weight-modifying agent remains debated.
Aim: This review evaluates the mechanistic basis, clinical evidence, comparative efficacy, and safety profile of metformin with respect to body weight outcomes in type 2 diabetes.
Material and Methods: A narrative review was conducted using PubMed, encompassing publications from 1995 to 2026. Eligible study types included randomised controlled trials, observational studies, systematic reviews, and meta-analyses reporting weight-related or mechanistic outcomes relevant to metformin therapy.
Results: Metformin reduces body weight through AMPK-mediated inhibition of hepatic lipogenesis, appetite suppression via incretin pathways, and gut microbiota modulation. Pooled clinical evidence demonstrates a modest but consistent weight reduction of approximately 1.5 to 2.5 kg versus placebo, with durability reported over long-term follow-up. This effect is substantially inferior to GLP-1 receptor agonists and tirzepatide, which produce reductions of 10–20% in major trials. Metformin's safety profile is characterised by manageable gastrointestinal adverse effects, negligible hypoglycaemic risk, and a clinically important association with vitamin B12 depletion on long-term use.
Conclusions: Metformin should not be regarded as a primary weight loss agent but retains meaningful value as a globally accessible and well-tolerated component of metabolic management in type 2 diabetes.
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Copyright (c) 2026 Aleksandra Jóźwik-Szymańska, Natalia Kostecka, Laura Mikuła, Zuzanna Bogdan-Groszyk, Aleksandra Szredzka, Jan Kucharski, Aleksandra Makulec, Katarzyna Otrębska, Dominika Lewandowska
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