Used as a stable isotope-labeled internal standard in mass spectrometry and nuclear magnetic resonance (NMR) studies to track metabolic pathways involving nucleotide synthesis and degradation. Enables accurate quantification of deoxyuridine and related metabolites in biological samples such as plasma, urine, and cell extracts. Supports research in DNA metabolism, antiviral drug mechanisms, and cancer biology by providing a non-radioactive tracer with high detection specificity. Also employed in kinetic studies to measure nucleoside turnover rates in vivo and in vitro.