KOPROSTEINE is a modified form of cysteine which is non-toxic and stable than cysteine and itis rapidly converted into cysteine and carbon dioxide inside the cells. Cysteine is a key component and building block of the antioxidant glutathione. Cysteine with thiol group is responsible for anti-glycation of collagen and is effective against vesicants and percutaneous chemical agents. Ability of Koprosteine to bind copper ions that are essential for tyrosinase activity responsible for melanin inhibition.