The body needs fatty acids to survive and is able to make all but two of them: linoleic acid (LA), in the omega-6 family, and alpha-linolenic acid (ALA) in the omega-3 family. These two fatty acids must be supplied by the diet and are therefore considered essential fatty acids (EFAs).

Omega-6 fatty acids are well-supplied in the diet by meat and vegetable oils. However, not all omega-6 fatty acids are of equal value. Arachidonic acid (AA) tends to be unhealthy because it is the precursor of inflammatory eicosanoids — such as 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, is an important fatty acid that plays a beneficial role in healthy prostaglandin (PGE1) formation and pro-inflammatory mediator reduction.98,99

Evening primrose is a wildflower that is now grown commercially. Evening primrose oil (EPO) from Jarrow Formulas® contains an omega-6 essential fatty acid, gamma-linolenic acid (GLA), which is the active ingredient and has been recommended for its fluid-regulating properties.