trans-Vaccenic acid-d13 is deuterium labeled trans-Vaccenic acid (HY-113427). trans-Vaccenic acid is a naturally occurring trans fatty acid (TFA). trans-Vaccenic acid inhibits nasopharyngeal carcinoma (NPC) cell growth and induces apoptosis through the inhibition of Bad/Akt phosphorylation. trans-Vaccenic acid is a precursor for the synthesis of saturated fatty acid in the rumen and of conjugated Linoleic acid (CLA) at the tissue level. trans-Vaccenic acid exerts hypolipidemic effects in a rat model of obesity[1][2][3][4].