Lysine is an essential amino acid essential amino acids are not produced by the body so they must be supplied from the diet or by taking supplements lysine is found in foods such as lentils red meat pork poultry sardines nuts eggs soya beans brewers yeast and dairy products lysine is an essential amino acid essential amino acids are not produced by the body so they must be supplied from the diet or by taking supplements lysine is found in foods such as lentils red meat pork poul