As it is known to most of the people that amino acids are the building blocks of proteins. And a large number of tissue, muscles and cells are made up of amino acids. Amino acids can be procured from animal source as well as non-animal source.L-cysteine is one of those sulfur-containing amino acids which helps the body to function properly.It may be used as a supplement for cell culture media in many industries. And its deficiency may lead to disturbance in the whole body function. Vegetarians are likely to suffer from L-cysteine deficiency because it is normally found in red meat, seafood etc. And this is a non-animal source of l-cysteine which is very beneficial for vegetarians also.