AOD-9604 is a modified 16-amino-acid fragment of human growth hormone (hGH 177–191) with an N-terminal tyrosine and a C-terminal disulfide bridge, originally developed by Metabolic Pharmaceuticals (Australia) as an orally active, lipolytic peptide that retains the fat-reducing activity of hGH while eliminating its growth-promoting and hyperglycemic effects. AOD-9604 acts primarily by mimicking the lipolytic domain of hGH, binding to the β₃-adrenergic receptor pathway in adipocytes and stimulating triglyceride breakdown and fatty acid oxidation without activating the hGH receptor (GHS-R) or significantly elevating IGF-1, thereby avoiding the anabolic, diabetogenic, and proliferative concerns associated with full-length hGH. Extensive preclinical studies in obese rodents (ob/ob, db/db, and diet-induced models) and early-phase human trials demonstrated dose-dependent reductions in body fat mass (5–10% over 12–24 weeks), inhibition of lipogenesis, improved lipid profiles, and enhanced energy expenditure with no adverse effects on glucose tolerance or insulin sensitivity. Clinical development progressed to Phase IIb for obesity (2004–2007), where it showed statistically significant fat loss versus placebo, particularly in visceral and trunk regions;  Subsequent research has explored its potential in osteoarthritis (intra-articular administration reduced cartilage degradation in rabbit models), post-bariatric weight maintenance, and sarcopenic obesity.