N-Acetyl-S-(2-carbamoylethyl-d4)-L-cysteine is deuterium labelled form of N-Acetyl-S-(carbamoylethyl)-L-cysteine (A171870), which is the urinary metabolite of Acrylamide (AA). Acrylamide is formed during the heating of food and is classified as a genotoxic carcinogen.