Carnitine is made in the body from the amino acids, lysine and methionine.* Carnitine is often called an amino acid because of its chemical makeup, however it is actually a vitamin-like nutrient, related in structure to the B vitamins.* It plays an essential role in transporting fatty acids into the muscles for energy, and is needed to transport these substances into the heart muscle.* Nearly 60% of the energy for the heart muscle is supplied by fatty acids.* It is also one of the two amino acids which promote sperm motility.*