Lysine is an essential amino acid, which means your body cannot manufacture it so it must be obtained through the diet or by supplementation. Lysine is an essential component of all proteins and works with other essential amino acids to maintain growth, lean body mass, and the body"s store of nitrogen. Lysine acts as a precursor for several other amino acids, including L-Citrulline (needed for normal protein metabolism) and L-carnitine (needed for fat metabolism). Lysine is crucial for the formation of collagen, a major part of the body"s connective tissues and appears to help the body absorb and conserve calcium and may reduce its excretion. L-Lysine has shown to be helpful reducing cold sores by up to 50%, L-lysine supports immune system function, L-lysine may support a healthy cardiovascular system. L-lysine supports calcium absorption, making it more available for biological functions. Lysine contributes to energy production when converted to acetyl coenzyme A, one of the principal fuels for the Krebs cycle. Lysine is needed for growth and to help maintain nitrogen balance in the body. L-lysine has many other functions in the body because it is incorporated into many proteins, which are used by the body for a variety of purposes. Lysine supports a healthy immune system.