How do Dual GLP-1/GIP Receptor Agonists Differ from GLP-1 Agonists for Diabetes Management: A Systematic Review

Abstract

Introduction: Type 2 diabetes is a chronic metabolic disorder driven by insulin resistance and impaired β-cell function. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have become central to diabetes management by improving insulin secretion, reducing glucagon, promoting weight loss, and lowering cardiovascular risk. Dual GLP-1/glucose-dependent insulinotropic polypeptide (GIP) receptor agonists, such as tirzepatide, represent an emerging therapeutic class designed to enhance metabolic outcomes by activating complementary incretin pathways. This review evaluates how dual GLP-1/GIP agonists differ from GLP-1 RAs in mechanism, efficacy, safety, and therapeutic potential.

Methods: A systematic review was conducted using PubMed, Scopus, and the Cochrane Library to identify randomized trials, meta-analyses, and observational studies published from 2010 to 2025. Studies included adults with type 2 diabetes and directly compared dual GLP-1/GIP agonists with GLP-1 RAs. Primary outcomes were hemoglobin A1c reduction and weight change; secondary outcomes included safety, cardiovascular measures, and β-cell function.

Results: Across phase 3 trials, dual agonists achieved greater reductions in hemoglobin A1c (up to 2.4%) and body weight (up to 22%) compared to GLP-1 RAs. These effects reflect synergistic actions on insulin secretion, glucagon suppression, appetite regulation, and adipocyte metabolism. Dual agonists also demonstrated higher rates of normoglycemia and durable glycemic control, with gastrointestinal side effects similar to GLP-1 RAs. Preliminary data suggest improvements in blood pressure, lipid levels, and inflammatory markers, although dedicated cardiovascular outcome trials remain ongoing. Beyond diabetes, dual agonists show therapeutic potential in obesity, obstructive sleep apnea, and steatohepatitis

Discussion: Dual GLP-1/GIP agonists differ from GLP-1 RAs by activating two incretin pathways, resulting in superior glucose lowering, more pronounced weight reduction, and broader metabolic benefits. These advantages appear without added safety concerns. Distinct GIP-mediated effects on adipose tissue and central appetite pathways contribute to their enhanced efficacy.

Conclusion: Dual GLP-1/GIP receptor agonists represent a major advancement over GLP-1 RAs by delivering deeper glycemic improvement and greater weight loss through combined hormonal activation. Pending results from cardiovascular outcome trials, these agents may reshape diabetes management, particularly for individuals requiring substantial metabolic improvement beyond what GLP-1 RAs alone can provide.