Buy L-Carnitine 5-Pack 600mg Online

L-Carnitine (CAS 541-15-1, C7H15NO3, molecular weight 161.20 Da) is a quaternary ammonium compound synthesised in the body from lysine and methionine, and its role is mechanical rather than signalling. Long-chain fatty acids destined for beta-oxidation are activated in the cytosol to fatty acyl-CoA, but the inner mitochondrial membrane is impermeable to acyl-CoA, so the molecule cannot reach the enzymes that would oxidise it. The carnitine shuttle solves this in three steps: carnitine palmitoyltransferase 1 on the outer membrane swaps the CoA for carnitine, forming acylcarnitine; a translocase exchanges acylcarnitine inward for free carnitine outward; and carnitine palmitoyltransferase 2 on the inner membrane restores the CoA inside the matrix. CPT1 is the rate-limiting step of fatty acid oxidation and is inhibited by malonyl-CoA, the first committed intermediate of fatty acid synthesis — which is how a cell avoids burning and building fat at the same time. Carnitine availability therefore constrains long-chain fatty acid oxidation but does not by itself accelerate it when malonyl-CoA is high.