Ethyl cysteinate is derivative of semi-essential proteinogenic amino acid Cysteine. Ethyl cysteinate is widely used in food additive, cosmetic, pharmaceutical area. Ethyl cysteinate is membrane-permeable, readily enters peripheral tissues and the brain, and increases intracellular pools of cysteine in these tissues via a membrane-associated carboxylesterase. The increased availability of cysteine directly alters the redox status of cells and enhances glutathione production. The enhanced biovailability of L-cysteine and L-glutathione would also promote the direct formation of the S-nitrosothiols, L-S-nitrosocysteine and L-S-nitrosoglutathione and the overall S-nitrosylation status of functional proteins in cells.