(±)5-HEPE is produced by non-enzymatic oxidation of EPA. It contains equal amounts of 5(S)-HEPE and 5(R)-HEPE. The biological activity of (±)5-HEPE is likely mediated by one of the individual isomers, most commonly the 5(S) isomer in mammalian systems. EPA can be metabolized to 5-HEPE in human and bovine neutrophils, and human eosinophils, which is further metabolized to 5-oxoEPE and LTB5.{11149,11166,11167} The 5-series metabolites of EPA, namely 5-HEPE, 5-oxoEPE, and LTB5, have significantly decreased biological effects compared to the arachidonic acid-derived metabolites.{11167}