Lysine is an α-amino acid which is used by animal cells in the protein synthesis process. In humans and many other animals, it is an essential amino acid, meaning the body does not synthesize it quickly enough to meet demand and it must be obtained from dietary sources. Lysine can be obtained from high-protein foods, such as eggs, certain fish meat, beans, red meat, poultry, peas, and cheese. In many countries it is also available in supplement form, often taken orally.
