E-cholesterol Alkyne is an omega-terminal alkyne-containing modified lipid. The terminal alkyne group can be used in a highly specific linking reaction with azide-containing reagents, known as ‘Click chemistry’, in the presence of a Cu-containing catalyst. E-Cholesterol Alkyne (19-ethynylcholesterol) is a versatile, sensitive, and easy-to-use tool for tracking cellular cholesterol metabolism and localization, as it allows for manifold detection methods including mass spectrometry and fluorescence microscopy.