This compound is primarily used in biochemical research and pharmaceutical development, particularly in the study of metabolic pathways and drug metabolism. It serves as a labeled internal standard in mass spectrometry and chromatography for the accurate quantification of cysteine-containing compounds in biological samples. The deuterium labeling (d3) enhances its utility in tracing and analyzing metabolic processes with high precision. Additionally, it is employed in the development of targeted therapies, especially in cancer research, where it helps in understanding the role of cysteine derivatives in cellular mechanisms and drug interactions. Its application extends to investigating the pharmacokinetics and pharmacodynamics of new drug candidates, ensuring their efficacy and safety.