L-Carnitine (Levocarnitine) vs LC120

L-Carnitine (Levocarnitine)

L-carnitine is a small quaternary ammonium compound made in the liver and kidney from the amino acids lysine and methionine. It is not a peptide, and only the L-stereoisomer is recognised by the enzymes and transporters that handle carnitine. Most carnitine in the diet comes from meat and dairy foods, and the great majority of the body's store is held in skeletal and cardiac muscle. Its biochemistry has been worked out in detail, and there is a large human research literature, including work on inherited disorders of carnitine transport. Those human studies vary widely in design and quality, and their findings are often inconsistent.

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 L-Carnitine (Levocarnitine) acts

Carnitine's best-characterised role is moving long-chain fatty acids into mitochondria. Carnitine palmitoyltransferase 1 (CPT1), on the outer mitochondrial membrane, transfers the fatty acyl group from coenzyme A to carnitine; carnitine–acylcarnitine translocase carries the acylcarnitine across the inner membrane; and CPT2 on the matrix side converts it back to acyl-CoA for beta-oxidation. CPT1 is inhibited by malonyl-CoA, a control point linking fatty acid and carbohydrate metabolism. Carnitine also accepts surplus acyl groups from coenzyme A, and the acylcarnitines formed can leave the cell, which is why blood acylcarnitine profiles are used in metabolic research and screening.

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: L-Carnitine (Levocarnitine), Amino acid derivative (non-peptide); LC120, Identity not established
• Molecular weight: L-Carnitine (Levocarnitine), 161.20 g/mol; LC120, not recorded
• Molecular formula: L-Carnitine (Levocarnitine), C7H15NO3; 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.