L-Lysine is an essential amino acid which is not manufactured within the body and must be obtained through diet or by supplementation. Amino acids such as L-Lysine are required to maintain good health. L-Lysine helps the body absorb calcium, and supports the creation of collagen, which builds connective tissue and helps maintain lean muscle tissue and burn fat. L-Lysine is also linked to the production of carnitine, which converts fatty acids into energy, which in turn may reduce cholesterol in the blood stream. Additionally, L-Lysine may support a healthy immune system. Lysine may strengthen circulation and may help the immune system manufacture antibodies.