Lamberts® supplies a wide range of Evening Primrose supplements and this is one of our most popular. Each capsule provides a high quality oil specially selected for its purity and consistent GLA level, and each capsule also provides the full RDA of vitamin E. Evening primrose oil is still a popular supplement as the oil is one of the few natural sources of an Omega 6 fatty acid called Gamma-Linolenic Acid (GLA). Evening primrose is still widely recommended for use by women during their monthly cycle as well as for women going through the menopause.