Used as a stable isotope-labeled internal standard in mass spectrometry-based bioanalysis for quantifying bile acids in biological samples. Enables accurate detection and measurement in metabolic studies, particularly in research related to liver function, gastrointestinal diseases, and disorders of bile acid metabolism. Its deuterated structure provides a distinct mass signature, improving specificity and sensitivity in LC-MS/MS workflows. Also applied in pharmacokinetic studies to track bile acid dynamics without interference from endogenous compounds.