The 8 Amino Acids You Need
Although the body makes plenty of amino acids itself (20 to be exact), it also needs essential amino acids, which are not inherent and must be obtained through food or supplements.
"These eight essential amino acids further assist in the stimulation of collagen and elastin production and other functions of the skin and body. One amino acid cannot be substituted for another, and the human body is incapable of manufacturing essential amino acids on it's own. - Vic Narurkar, MD.
Even if just one is missing, the body can't repair itself and create new proteins.
Isoleucine
Leucine
Lysine
Methionine
Phenylalaline
Threonine
Tryptophan
Valine