We searched the primary literature in PubMed, Embase and SciELO from inception to June 2025, using the terms “diabetes”, “type 2 diabetes mellitus”, “glucagon-like peptide-1”, “L-cell”, “metabolic surgery”, “jejunostomy”, “GLP-1 receptor agonists” as well as their combinations. Here, GCG is linked to type 2 diabetes mellitus.