L-Lysine, an essential amino acid, is required for healthy growth, tissue repair, enzyme production and strengthening immunity. L-Lysine is a protein-building block that strengthened and nourishes the structural, circulatory and immune systems. L-Lysine enhances the assimilation and absorption of calcium, and it ensures the formation of cartilage, bone, connective tissues and collagen. L-Lysine is not produced by the body and must be obtained via the diet. Some natural food sources for L-Lysine include lima beans, kidney beans, potatoes, corn, red meat, fish and milk. L-Lysine is necessary for helping the immune system produce antibodies that are necessary for warding off viral infections, making it beneficial for treating herpes, cold sores, mouth ulcers, and fevers. L-Lysine is also beneficial for regulating glands, controlling acid/alkaline balance and assisting with the assimilation of all amino acids. L-Lysine deficiencies may include fatigue, moodiness, anemia, poor concentration, reproductive problems and slow development. L-Lysine supplementation helps maintain the health of the structural, circulatory and immune systems.