The amino acids that are to be supplied through diet are called as essential amino acids. They cannot be produced by the body. These are nine essential amino acids- valine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine and tryptophan.
Arginine and histidine are called semi-essential amino acids as they can be partly synthesized in the human body.
Arginine is not essential for infants.
Arginine and Histidine are not essential for adults.
Nonessential amino acids The amino acids that can be synthesized by the body are called non essential amino acids. There are eleven in number, alanine, arginine, aspartate, cysteine, glutamate, glutamine, glycine, proline, serine, tyrosine, pyrrolysine.