Evening primrose oil (EPO) contains an omega-6 essential fatty acid, gamma-linolenic acid (GLA), which is felt to be the active ingredient. EPO has been studied in a wide variety of disorders, particularly those affected by metabolic products of essential fatty acids. ‡
Evening primrose has served as food and medicine at throughout history, often for upset stomach and respiratory infections. Native Americans ate the boiled, nutty-flavored root, and used leaf poultices from the plant for bruises and hemorrhoids. European settlers took the root back to England and Germany, where it was introduced as food and became known as German rampion because it grew as a crawling vine. The plant was also a Shaker medicine, sold commercially.
A circle of leaves grows close to the ground around evening primrose stems after the first year it is planted. Flowers bloom after sunset, June through September, or on overcast days during the second year. Stems are branched, with alternate leaves (in other words, the leaves grow on both sides of the stem at alternating levels). This monograph focuses on the seed from which the oil is extracted.
Oil is extracted from the seeds and prepared as medicine using a chemical called hexane. The seeds contain up to 25% essential fatty acids including linoleic acid (LA) and gamma-linolenic acid (GLA). Both LA and GLA belong to the omega-6 family of fatty acids. The vast majority of North Americans get too much omega-6 fatty acid in their diet.
The body needs a balance of omega-3 and omega-6 fatty acids to function normally. Omega-3 oils can be found in cold water fish such as salmon or in dietary supplements. ‡
Today, evening primrose seed oil (EPO) is used primarily to relieve the itchiness associated with certain skin conditions (such as eczema and dermatitis) and to ease breast tenderness from premenstrual syndrome (PMS) or other causes. Some of the common uses for EPO include: ‡
Allergies: EPO has been reported effective for rashes, particularly skin rash or hives (itching).
Eczema: Eczema symptoms include redness and scaling in addition to itching. There are over 30 positive human studies reporting benefits in eczema and dermatitis when using EPO. A review of including 1,207 patients reported that EPO was beneficial for skin conditions, including itching, crusting, edema (fluid, swelling), and redness. EPO can be used in children and adults for skin conditions.
PMS: EPO can help with symptoms of PMS, including mood swings, bloating, and breast tenderness.
Arthritis: Clinical trials of EPO for arthritis began in the early 1980s, focusing over the following years on patients with rheumatoid arthritis (RA).
Diabetic Neuropathy: Diabetic neuropathy is a nerve condition caused by diabetes. Patients experience numbness, tingling, pain, burning, or lack of sensation in the feet and legs. EPO may be beneficial in reducing these symptoms.
Breast Pain: EPO is officially licensed for the treatment of breast pain (mastalgia) in the United Kingdom and considered first-line therapy in several European countries. EPO was found effective at decreasing breast pain in several clinical studies, however, other studies report no benefit.
Menopausal symptoms: EPO has gained some popularity for treating hot flashes
It is the balance of omega-6 (such as GLA) and omega-3 (such as fish oil) that helps keep a body healthy. Taking an omega-3 fatty acid supplement along with EPO may be more beneficial for health than EPO alone in these and other conditions.
The main active ingredient in EPO is an omega-6 fatty acid known as gamma-linolenic acid (GLA).