In addition to providing sustenance and its nutritive value, evening primrose oil is a rich source of gla (Gamma linolenic acid), which can help in regulating the production of hormone like substances called prostaglandins and has been historically use: to relieve premenstrual symptoms, lower blood cholesterol levels and improve circulation contains natural vitamin e which is an important antioxidant protecting cells from oxidative stress no other evening primrose oil supplement provides a purer or richer source of gla