AOD-9604 vs LC120

AOD-9604

AOD-9604 is a synthetic peptide based on the C-terminal segment of human growth hormone, with a tyrosine at its N-terminus and a disulfide bond. It was designed to test the idea that this short region carries some of growth hormone's activity on fat metabolism separately from the rest of the molecule. Work on it began with rodent studies of fat cells and whole-animal lipid metabolism, and the peptide later entered human clinical trials, whose published record is sparse. A smaller body of animal work has looked at cartilage in joint injury models. Unlike full-length growth hormone, it is not regarded as a growth hormone receptor agonist, which shapes how its reported activity is interpreted.

LC120

LC120 is a proprietary nutrient mixture, reported to contain L-carnitine, methionine, inositol and choline, rather than a single compound. The proportions of each ingredient have not been confirmed from published sources, and a mixture has no single formula or molecular weight. Each named component has a defined place in metabolism: L-carnitine carries long-chain fatty acids into mitochondria, methionine is an essential amino acid and the precursor of the methyl donor S-adenosylmethionine, choline is a precursor of phosphatidylcholine and acetylcholine, and inositol forms the core of the phosphoinositide lipids. The mixture itself has no published literature, so everything that can be said about it comes from studies of the components taken separately.

How AOD-9604 acts

AOD-9604 has been reported not to bind the growth hormone receptor with meaningful affinity and not to act through the IGF-1 axis, so its proposed actions differ from those of the whole hormone. Studies in isolated rodent fat cells and in obese mice examined lipolysis and lipogenesis, and some of that work implicated beta-3 adrenergic receptor pathways. A receptor that binds the fragment directly has not been identified. The cartilage studies used animal joint injury models and measured markers of cartilage matrix, and no mechanism for those observations has been established. Overall, the mechanistic literature is small and comes from a limited number of groups.

How LC120 acts

No mechanism has been described for the mixture, and its components are not known to share a target. L-carnitine is the substrate of the carnitine shuttle, which moves long-chain acyl groups into the mitochondrial matrix, where they undergo beta-oxidation. Methionine is converted to S-adenosylmethionine, the main methyl donor for the methylation of DNA, proteins and lipids. Choline provides the polar head group of phosphatidylcholine, which the liver needs to assemble and export very-low-density lipoproteins. Myo-inositol, the usual form of inositol, is incorporated into phosphatidylinositol and its phosphorylated derivatives, which carry signals inside cells. Whether the components alter each other's behaviour in combination has not been studied.

The records side by side

• Type: AOD-9604, Modified hGH fragment (176-191); LC120, Identity not established
• Length: AOD-9604, 16 amino acids; LC120, not recorded
• Molecular weight: AOD-9604, 1815.1 g/mol; LC120, not recorded
• Molecular formula: AOD-9604, C78H123N23O23S2; LC120, not recorded

Reading a comparison

A comparison places two records side by side; it does not merge them. Each description above is drawn from that compound's own record, and the two were not necessarily characterised by the same methods, at the same time, or to the same level of detail. Before comparing any attribute, it is worth establishing that both records describe the substance you think they describe — names are not identifiers, and two entries sharing a name can differ in salt form, stereochemistry or the convention used to state a mass. Where a figure carries no method beside it, the comparison is between two reported numbers rather than between two measurements.