12(S)-HEPE is a monohydroxy fatty acid synthesized from EPA by the action of 12-LO. Unstimulated neutrophils metabolize 12(S)-HEPE to 12(S),20-diHEPE, whereas stimulated neutrophils produce 5(S),12(S)-HEPE via the 5-lipoxygenase pathway.{6402} The competitive action of 12(S)-HEPE with arachidonic acid as a substrate for 5-LO in the formation of leukotrienes may provide a basis for the anti-inflammatory potential of ω-3 fatty acids.