A building block of protein structures within the muscle. (order in singles or 6 for retail outer)L lysine is an essential amino acid that the body does not make. This means that adequate levels need to be obtained from food and supplementation. L lysine is a building block of protein structures within the muscle, especially muscle and skin protein structures and bones. L lysine works in balance with the amino acid L arginine, and helps to prevent a high L arginine environment and decreases the occurrence of herpes viruses such as those seen with