– Cholesteryl heptadecanoate is a cholesterol ester (CE) formed by the condensation of cholesterol with heptadecanoic acid, a C-17 saturated fatty acid that does not occur in any natural animal or vegetable fat at high concentrations. As such, it is commonly used as an internal standard for the quantification of cholesterol esters by GC- or LC-mass spectrometry. CEs are major constituents of lipoprotein particles carried in blood and accumulate in the fatty acid lesions of atherosclerotic plaques. CEs of various fatty acids are major constituents of murine and human adrenal glands.