Evening primrose oil is one of the few natural sources of a polyunsaturated fate called Gamma- Linolenic Acid (GLA). GLA is the precursor of a particularly important prostaglandin called PGE1, which takes part in regulating the nervous, cardiovascular and reproductive systems, skin condition and other biological functions.
Whilst the body can make GLA from linoleic acid (the Omega 6 fatty acid present in vegetable oils) this conversion is sometimes slow or partially blocked. Hence, a dietary source of GLA can be very useful to the body in by-passing the conversion process, and numerous clinical trials have established that GLA supplements can be effective in certain situations.
The body produces several types of prostaglandin; some promote inflammation, others control it. The GLA in evening primrose oil is directly converted to important anti-inflammatory prostaglandins, which accounts for most of the supplement's therapeutic effects. In addition, GLA is an important component of cell membranes. The recommended therapeutic dose for evening primrose oil is generally 1000mg three times a day. This supplies 240mg of GLA a day. To get an equivalent amount of GLA from other sources you would need to take 1000mg of borage oil or 1500mg of blackcurrant oil each day. Evening primrose oil or borage oil can also be applied topically to the fingers to ease the symptoms of Raynauds's disease.