Amino acids are organic compounds composed of nitrogen, carbon, hydrogen, and oxygen, along with a variable side chain group. Your body needs 20 different amino acids to grow and function properly. Though all 20 of these are important for your health, only nine amino acids are classified as essential.
These are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
Unlike nonessential amino acids, essential amino acids can’t be made by your body and must be obtained through your diet. The best sources of essential amino acids are animal proteins like meat, eggs, and poultry. When you eat protein, it’s broken down into amino acids, which are then used to help your body with various processes such as building muscle and regulating immune function.