| Histidine (H) |
| Isoleucine (I) |
| Leucine (L) |
| Lysine (K) |
| Methionine (M) |
| Phenylalanine (F) |
| Threonine (T) |
| Tryptophan (W) |
| Valine (V) |
Essential amino acids
Essential amino acids (EAAs) are needed for the synthesis of proteins in an organism but cannot be synthesized by the organism itself. Therefore EAAs must be present in the diet. There are nine EAAs for human diet: Valine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, and methionine.