Used as a stable isotope-labeled internal standard in mass spectrometry and liquid chromatography-mass spectrometry (LC-MS) assays for accurate quantification of bile acids in biological samples. Its deuterated structure allows clear differentiation from endogenous cholic acid, improving measurement precision in metabolic studies, clinical diagnostics, and pharmacokinetic research. Also employed in studies of lipid metabolism, liver function, and gut microbiome interactions where accurate tracing of bile acid pathways is required.