L-carnitine Other names: Levocarnitine

Levocarnitine as a factor is necessary in the transport of long-chain fatty acids into the mitochondria-facilitating the oxidation of fatty acids rather than their incorporation into triglycerides.

Levocarnitine is present as a natural constituent in animal tissues, micro-organisms and plants. In man the physiological metabolic requirements are met both by the consumption of food containing carnitine and the endogenous synthesis in the liver and kidneys from lysine with methionine serving as the methyl donor. Only the Lisomer is biologically active, playing an essential role in lipid metabolism as well as in the metabolism of ketone bodies as branched chain-amino-acids. Levocarnitine as a factor is necessary in the transport of long-chain fatty acids into the mitochondria-facilitating the oxidation of fatty acids rather than their incorporation into triglycerides. By releasing CoA from its thioesters, through the action of CoA; carnitine acetyl transferase, levocarnitine also enhances the metabolic flux in the Kreb’s cycle; with the same mechanism it stimulates the activity of pyruvate dehydrogenase and in skeletal muscle, the oxidation of branched-chain amino acids.

Levocarnitine is thus involved, directly or indirectly in several pathways so that its availability should be an important factor controlling not only the oxidative utilization of fatty acids and ketone bodies but also that of glucose and some amino acids.

The absorbed levocarnitine is transported to various organ systems via the blood. The presence of membrane-bound proteins in several tissues including red blood cells that bind carnitine, suggest that a transport system in the blood and a cellular system for the collective uptake is present in several tissues. Tissue and serum carnitine concentration depend on several metabolic processes, carnitine bio-synthesis and dietary contributions, transport into and out of tissues, degradation and excretion may all affect tissue carnitine concentrations.

It has been demonstrated that pharmacokinetic parameters increase significantly with dosage. Apparent bioavailability in healthy volunteers is about 10-16%. The data suggests a relationship between maximal plasma concentration/dosage, dosage, plasma AUC, dosage/urinary accumulation. Maximum concentration is reached about four hours after ingestion.

Levocarnitine is a naturally occurring body substance in human beings, plants and animals. Levocarnitine products are used to bring the level of levocarnitine in the body up to those found naturally. Appropriate pre-clinical studies have been undertaken and show no signs of toxicity at normal therapeutic doses.