Evening Primrose Evening primrose is an attractive herb that grows in mild climate of North American and Europe as well as many other areas of the world with similar climates. However, evening primrose is cultivated and processed primarily in Canada and the United States. Evening primrose plants may grow anywhere from 3 to 7 feet in height. A unique characteristic of the evening primrose plant is that it will bloom throughout the summer, but its flowers each last only one day, opening as the sun goes down and then dying away in sunlight (hence its name "Evening Primrose"). About 2 inches in length, the seeds of the evening primrose are used to produce the volatile oil that is used in medicines and cosmetics. Evening primrose oil contains substantial amounts of polysaturated omega-6 fatty acids, essential fatty acids (EFAs) which are needed by the body to regulate a number of activities including insulin utilization, heart function, and mood. Since the body does not produce EFAs, they must be ingested through proper diet or supplementation. In addition to omega-6 fatty acids, evening primrose oil contains linoleic acid and gamma-linolenic acid (GLA). Both linoleic acid and GLA are believed to have very positive health and medicinal indications. Linoleic acid may affect how the body utilizes insulin, maintains weight, and fights cancer and heart disease. GLA may help to inhibit the body's production of chemicals that cause inflammation. Consequently, evening primrose oil has been used in connection with inflammatory conditions including both rheumatoid arthritis and asthma. Some studies have also suggested that evening primrose oil may be useful in treating chronic fatigue syndrome, but more research is needed before evening primrose oil can be recommended for that condition. Evening primrose oil may help to relieve pre-menstrual syndrome (PMS), symptoms of menopause, and breast pain due to hormonal changes during menstruation. Supplementary GLA, such as is supplied by evening primrose oil, appears to relieve some PMS symptoms. However, many of the suggested uses of evening primrose seed oil have not been substantiated by sound clinic studies and research. Both oral and topical forms of evening primrose oil have also been studied for treating acne, eczema, psoriasis, and other skin conditions. When used as a topical application on the skin, evening primrose oil has moisturizing and softening effects. Additional research indicates that individuals suffering from diabetes, scleroderma, Sjorgen's syndrome, and tardive dyskinesia may be deficient in GLA. In preliminary studies, supplementation with Evening Primrose Oil aided individuals with these conditions. Dosage Most experts have recommended 3000 to 6000 mg of Evening Primrose Oil per day, which, when standardized, provides approximately 270-540 mg of GLA. EPO is usually standardized to contain 8% gamma-linolenic acid. Supporting Literature De La Cruz JP, Martin-Romero M, Carmona JA, Villalobos MA, Sanches DC. Effect of evening primrose oil on platelet aggregation in rabbits fed an atherogenic diet. Thromb Res. 1997;87(1):141-149. Horrobin DF. Essential fatty acid metabolism in diseases of connective tissue with special reference to scleroderma and to Sjogren's syndrome. Med Hypotheses 1984;14:233-247. Keen H, Payan J, Allawi J, et al. Treatment of diabetic neuropathy with gamma-linolenic acid. Diabetes Care 1993;16:8-15. Leventhal LJ, Boyce EG, Zurier RB. Treatment of rheumatoid arthritis with black currant seed oil. Br J Rheumatol. 1994;33(9):847-852. Mansel RE, Pye JK, Hughes LE. Effects of essential fatty acids on cyclical mastalgia and noncyclical breast disorders. In Omega-6 Essential Fatty Acids: Pathophysiology and Roles in Clinical Medicine, ed. DF Horrobin. New York: Alan R Liss, 1990, 557-566. Schalin-Karrila M, Mattila L, Jansen CT, et al. Evening primrose oil in the treatment of atopic eczema: effect on clinical status, plasma phospholipid fatty acids and circulating blood prostaglandins. Br J Dermatol 1987;117:11-18. Vaddadi KS, Gilleard CJ. Essential fatty acids, tardive dyskinesia, and schizophrenia. In Omega-6 Essential Fatty Acids: Pathophysiology and Roles in Clinical Medicine. Horrobin DF (ed). New York: Alan R Liss, 1990, 333-342.