Carnitine is really not an amino acid, but because of the close structural sameness, it is normally classed with amino acids, and is also known as vitamin BT. It is available as D-carnitine, L-carnitine, DL-carnitine as well as acetyl-L-carnitine, but with L-carnitine being the most popular type. L-Carnitine is synthesized from the essential amino acids lysine and methionine, but enough vitamin B1 (thiamine) and B6 (pyridoxine) must be available.
Unlike a true amino acid, it is not used in protein synthesis nor as neurotransmitter, but is used for long-chain fatty acid transport and is required for entry of these long-chain fatty acids into the mitochondria of the cell, as well as for the removal of short-chain organic acids from the mitochondria, which frees the intra-mitochondrial coenzyme.
It is therefore important for the energy supply within the cell, as well as muscles, assists in preventing fatty build-up in areas such as the heart, liver, and skeletal muscles.
It may also reduce the risk of poor fat metabolism in diabetes, alcohol-induced fatty liver as well as the risk of heart problems. Carnitine has also been shown to improve the antioxidant effect of vitamin C as well as E.