L-Carnitine is a nitrogenous compound essential for energy production and fat metabolism. Our body makes it in the liver and kidneys and stores it in the skeletal muscles, heart, brain and sperm. Carnitine exists in two isomeric forms: L-Carnitine and D-Carnitine, of which L-Carnitine is the physiological active form. Usually, our body can make Carnitine from two essential amino acids, methionine and lysine in the liver and kidneys. Its formation requires the presence of co-factors such as vitamin C, niacin, vitamin B6 and iron. Some people, however, may not have enough Carnitine because their bodies cannot make enough or can't transport it into tissues so it can be used. Some other conditions, such as angina, intermittent claudication and usage of certain medications are also among the causes of low levels of Carnitine in the body.