Used as an internal standard in mass spectrometry for accurate quantification of 27-hydroxycholesterol in biological samples. Enables precise measurement in studies related to cholesterol metabolism, oxidative stress, and inflammatory diseases. Commonly applied in research on atherosclerosis, neurodegenerative disorders, and hormone-dependent cancers due to the role of 27-hydroxycholesterol in these pathways. The deuterated form ensures minimal interference and high analytical accuracy in LC-MS/MS workflows.