Human growth hormone (hGH) is a 191-amino-acid protein with a broad spectrum of effects: it promotes growth, protein synthesis and lipolysis (fat breakdown). Research in the 1990s showed that the lipolytic activity of GH is primarily located in the C-terminal region of amino acids 176–191.
HGH Fragment 176-191 (also known by the development name AOD9604) is a synthetic peptide corresponding exactly to this region. It activates fat-degrading enzymes in adipose tissue without binding to the hGH receptor and thus does not exert growth-promoting or blood-glucose-raising effects.
Heffernan et al. published data on AOD9604 in obese mouse models in Endocrinology (2001). The studies showed significant reductions in body fat and increased fat oxidation without the side effects typical of full GH, such as insulin resistance.
An important distinguishing feature from full GH: HGH Fragment 176-191 does not influence IGF-1 levels or insulin sensitivity to any relevant degree. This makes it a valuable tool for studying adipogenic and lipolytic signalling pathways.
Metabolic Pharmaceuticals conducted Phase I/II studies with AOD9604 in humans but was unable to demonstrate efficacy in larger Phase 3 studies for the intended obesity indication. In fundamental research on fat metabolism, however, HGH Fragment 176-191 remains a relevant compound. Studien Peptide provides it as a high-purity peptide for research purposes.
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