Non-essential amino acid :
Essential amino acids are those which can't be synthesised in the body and must be taken in the diet. Alanine can be synthesized from pyruvate by transamination in a single step. So, alanine is not a dietarily essential amino acid. Semi-essential amino acids: Those which can be synthesized in body but to some extent.
Tryptophan
Tyrosine
Arginine
Histidine
Classification and metabolism of amino acids