(5Z,8Z,11Z,14Z)-Ethyl Icosa-5,8,11,14-tetraenoate-d5 is an intermediate used in the synthesis of Eicosapentaenoic Acid-d5 (E477802), which is an important polyunsaturated fatty acid of the marine food chain that serves as a precursor for the prostaglandin-3 and thromboxane-3 families. It differs from arachidonic acid (the eicosatetraenoic acid that is a precursor for the prostaglandin and thromboxane-2 families) by the extra double bond between the third and fourth carbons from the “methyl end” of the molecule. Antilipemic.