Your body needs fatty acids to survive, though it is able to make all but two of them: linoleic acid, in the omega-6 family, and alpha-linolenic acid (ALA) in the omega-3 family. These two fatty acids must be supplied from dietary sourced and are therefore considered essential fatty acids.
Omega-6 fatty acids are well-supplied via consumption of meat and vegetable oils. However, not all omega-6 fatty acids are of equal value. Arachidonic acid (AA) is the precursor of prostaglandin E2 (PGE2), thromboxane A2 and leukotriene B4, which promote inflammation. In contrast, gamma-linolenic acid (GLA), found in evening primrose oil, borage oil and black currant oil, benefits healthy prostaglandin (PGE1) formation and reduces inflammation.
Evening primrose is a wildflower that is also grown commercially. Evening primrose oil (EPO) from Jarrow Formulas® contains an omega-6 essential fatty acid, gamma-linolenic acid (GLA), the active ingredient that has been recommended for its fluid-regulating properties.