Like vitamins, Essential Fatty Acids (EFAs) are required for life. They must come from foods of supplements, because the human body cannot make them.  Linoleic Acid (LA) is an EFA. The production of GLA from dietary Linoleic Acid occurs only slowly, or may be blocked entirely in many people.  Yet GLA is a necessary precursor in the production of prostaglandins which, like hormones, regulate vital cell activities and determine the state of health of all cells, tissues and organs. Clinical studies in North America and Europe have demonstrated the value of GLA in managing a wide variety of disorders including Atherosclerosis, Diebetes Mellitus, Eczema, Multiple Sclerosis, Pre-menstrual Syndrome (PMS) and ADD (Attention Deficit Disorder).

Most Clinical studies that support the beneficial effects of GLA therapy have been conducted with Evening Primrose Oil (EPO).  Until studies of GLA therapy using GLA sources other than EPO have been conducted, EPO remains the only proven biologically effective source of GLA.

One study (Lawson L.D. & Hughes, B. G., Lipids, Volume 23, No. 4, 1988) indicates that when linoleic acid occupies a middle position on triglyceride molecules, it enhances absorption of fatty acids on outside positions. Evening Primrose Oil has linoleic acid on most of its middle positions, far more often than other GLA-containing oils, & most of its GLA is on outside positions.  The researchers conclude: "GLA in Evening Primrose Oil may be more efficiently absorbed than from other known GLA oils".  The other study (Manku et al, Journal of the American Oil Chemists Society, Volume 65, No.14, 1988) shows that Evening Primrose Oil forms DGLA, the precursor of the beneficial prostaglandin 1 series, in higher concentrations than other GLA-containing oils (borage, black currant, fungus).