How much evening primrose oil is recommended to help with menopause?

As of 2015, there is no recommended evening primrose oil dosage for help with menopause, states the National Center for Complementary and Integrative Health. Results from preliminary studies show a clear lack of evidence of its efficacy with menopausal and premenstrual syndrome symptoms.

Evening primrose oil is an herbal remedy with a high concentration of gamma-linolenic acid, states the American Cancer Society. GLA is an omega-6 fatty acid essential to many body processes while its anti-inflammatory effect helps in relieving symptoms of atopic dermatitis, eczema and breast pain. In addition, the body also converts GLA to prostaglandin E1, a hormone useful in contracting blood vessels.