All cells throughout the human body are enveloped by a membrane composed chiefly of essential fatty acids (EFAs) that play a major role in cellular function. A deficiency of EFAs makes it virtually impossible for cell membranes to perform the vital task of acting as a selective barrier to regulate the passage of certain materials in (i.e. nutrients, water) and out (i.e. waste products, toxin) of the cell. Evening Primrose Oil contains the omega-6 EFA, gamma linolenic acid (GLA). EFA deficiency can affect all organs in the body and is especially important to support the health of the skin, the bronchial system, our circulatory system, hormonal balance, response to allergens and healthy joints.