Antioxidant Protection For The Brain. 250 Milligrams. Acetyl-L-Carnitine is an amino acid found in most cells in the body including brain nerve heart liver and sperm cells. Acetyl L-Carnitine supports energy production via the metabolism of fatty acids to yield the universal energy molecule ATP. As an anitoxidant Acetyl-L-Carnitine helps to protect neurons affected by superoxide radicals.