Protein makes up the structure of all cells and tissues in the body, including muscle tissue, internal organs, tendons, skin, hair and nails. The 20 amino acids are the building blocks of protein. 12 of these 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. skin, hair and nails. Taurine is a non essential amino acid produced naturally in the body. It is also found in meat, fish, eggs and milk and is the second most abundant amino acid in muscle tissue. Protein makes up the structure of all cells and tissues in the body, including muscle tissue, internal organs, tendons, skin, hair and nails. The 20 amino acids are the building blocks of protein. 12 of these 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. skin, hair and nails. Taurine is a non essential amino acid produced naturally in the body. It is also found in meat, fish, eggs and milk and is the second most abundant amino acid in muscle tissue.