ATP Science Acetly L-CarnitineAcetyl L Carnitine You really only take Acetyl L Carnitine for one thing. Well according to science and well documented studies, Acetyl L Carnitine is an amino acid the body uses to turn fat into energy. So here's the technical low down Acetyl L Carnitine is essential for energy production in every cell of your body. It works by transporting fat, in the form of fatty acids, to the mitochondrial membrane where the fat is oxidized to produce energy