L-Lysine™ is concentrated form of the amino acid Lysine. Lysine is a critical building block for all protein in the body. It is an amino acid that cannot be created by the body, so it must be obtained by food or supplements. Grains and grasses are considered inadequate sources of Lysine. Using L-Lysine™ supplementation at times of stress is key to calcium absorption, building muscle protein, boosting the immune system and supporting the body's production of hormones, enzymes, and antibodies. Lysineis an amino acid most often deficient in horses' diets. L-Lysine™ is especially recommended for equine diets low in alfalfa, clover and soy.