The 20 amino acids are the building blocks of proteins. They can be combined in various ways to form hundreds of different proteins in the body. Protein makes up the structure of all cells and tissues in the body, including muscle tissue, internal organs, tendons, skin, hair and nails. 12 of the amino acids can be made in the body so are referred to as non-essential amino acids, whilst the other 8 are known as essential amino acids as they must be supplied in the diet.
