Carnitine tartrate is the supplement form of carnitine, a substance that plays a role in energy production. Your body typically makes enough carnitine to meet its needs. Therefore, it's not necessary for healthy adults to take carnitine supplements, according to the Office of Dietary Supplements. Nevertheless, due to its role in energy production, manufacturers market carnitine tartrate for sports performance and fat loss. Carnitine may provide benefits for heart patients.