RTA-GLP3 is the research designation for retatrutide (reta), an investigational peptide that acts on three metabolic receptors at once: GLP-1, GIP, and glucagon. That triple action earned it the "triple-G" nickname, and it has quickly become one of the most closely watched compounds in metabolic and weight research.
Research centers on how the GLP-1 arm curbs appetite and slows stomach emptying, the GIP arm supports insulin response and fat metabolism, and the glucagon arm raises energy expenditure and targets fat stored in the liver. Most studies focus on body weight, body composition, appetite, blood-sugar control, and liver fat. The added glucagon activity is what sets it apart from dual-agonist peptides.
Unlike most research peptides, retatrutide has been through large randomized human trials for obesity and type 2 diabetes, though it remains investigational and is not FDA-approved.