Used as a stable isotope-labeled internal standard in mass spectrometry (MS) and liquid chromatography-mass spectrometry (LC-MS) assays for the quantitative analysis of bile acids in biological samples. Its deuterated structure allows for accurate differentiation from endogenous chenodeoxycholic acid, improving measurement precision in metabolic studies, liver function assessments, and research on bile acid-related disorders such as cholestasis or gallstone disease. Also employed in pharmacokinetic studies to track metabolic pathways and transformations of bile acids without altering biological activity.