Evening Primrose Oil (EPO) is an extract of the Evening Primrose flower. Evening Primrose Oil (EPO) contains Gamma Linolenic acid (GLA), an essential fatty acid that gets converted into a hormone-like substance called prostaglandin E1. Although the body can manufacture GLA from dietary linoleic acid, it can be more effeciently utilized for body functions when supplied directly by these dietary sources. Evening Primrose Oil is an oil rich in essential fatty acids polyunsaturated fats that are as essential as vitamins and minerals for the maintenance of good health. It provides your body with a rich source of gamma linolenic acid (GLA), an omega 6 fatty acid.