The glucagon receptor component of triple agonism is studied specifically for its effects on liver fat. Preclinical studies in rodent models have shown that glucagon receptor activation reduces hepatic steatosis (fatty liver) by promoting fatty acid oxidation in hepatocytes. This has generated research interest in the context of non-alcoholic fatty liver disease (NAFLD) models.³

Research in animal models suggests that the combination of GLP-1-mediated appetite reduction and glucagon-mediated hepatic lipid clearance may address both caloric intake and fat accumulation through complementary mechanisms.

Unlike GLP-1 and GIP agonists, which primarily affect appetite and insulin secretion, glucagon receptor activation is associated with increased energy expenditure. Preclinical studies in rodent models have demonstrated that glucagon receptor agonism can increase resting metabolic rate and promote thermogenesis in brown adipose tissue.⁴

Triple agonism is hypothesized to produce a "two-front" approach to energy balance: reducing caloric intake (via GLP-1 and GIP pathways) while simultaneously increasing caloric expenditure (via glucagon pathways).

A key area of current research compares single-receptor (semaglutide class), dual-receptor (tirzepatide class), and triple-receptor (retatrutide class) agonism in metabolic models. This research investigates whether each additional receptor target produces incremental effects, and whether the combination introduces new pharmacological properties not seen with any individual receptor.⁵