Semi essential amino acids are those amino acids which can be synthesised by the body but at the expense of essential amino acids. It is therefore desirable to obtain them through foods/supplements. For example the amino acid tyrosine can be synthesised in the body from essential amino acid phenylalanine. read more
semi-essential amino acid An amino acid of which an adequate amount must be consumed in the diet to prevent the use of essential amino acids to synthesize it. An example is tyrosine. read more
An essential amino acid, or indispensable amino acid, is an amino acid that cannot be synthesized de novo (from scratch) by the organism, and thus must be supplied in its diet. The nine amino acids humans cannot synthesize are phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine, and histidine (i.e., F V T W M L I K H). read more