Non-essential amino acid :
Tryptophan
Tyrosine
Arginine
Histidine
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.
Classification and metabolism of amino acids