Humans use 20 amino acids for their goals, but there're approximately 260 of them in the world. People divide those amino acids into two types: essential and nonessential.
Usually, essential amino acids are gotten from the diet. Threonine, leucine, lysine, methionine, valine, isoleucine, tryptophan, and phenylalanine are included into this type.
There's also one component, histidine, that is called semi-essential, because it's necessary for development of children.