The objective of this study was to develop and produce a novel fusion protein that combines GLP-1 (glucagon-like peptide-1) and FGF21 (fibroblast growth factor 21), with the aim of achieving synergistic pharmacological effects through the targeting of dual pathways, followed by validation of these effects in a non-alcoholic steatohepatitis (NASH) model. The gene discussed is FGF21; the disease is metabolic dysfunction-associated steatohepatitis.