Evening Primrose Oil

by MedlinePlus

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. However, high-quality evidence for its use in most conditions is still lacking.

Synonyms

Echte Nachtkerze, EPO, fever plant, gamma-linolenic acid (GLA), herbe aux anes, Huile D'Onagre, kaempe natlys, King's Cureall, la belle de nuit, nachtkerzenol, night willow-herb, Oenothera communis Leveill, Oenothera graveolens Gilib, omega-6 essential fatty acid, Onagra biennis Scop, Onogra vulgaris , onagre bisannuelle, scabish, Spach, stella di sera, sun drop, Teunisbloem.

Evidence

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Uses based on scientific evidence

Eczema (children and adults)

Several small studies of eczema suggest benefits of taking evening primrose oil by mouth. Large well-designed studies are needed before a strong recommendation can be made. Evening primrose oil is approved for eczema in several countries outside of the United States.

Skin irritation (atopic dermatitis in children and adults)

Several small human studies of atopic dermatitis suggest benefits of taking evening primrose oil by mouth. Large well-designed studies are needed before a strong recommendation can be made. Evening primrose oil is approved for atopic dermatitis in several countries outside of the United States.

Breast cancer

Not enough information is available to advise the use of evening primrose oil for breast cancer. People with known or suspected breast cancer should consult with a qualified healthcare professional about possible treatments.

Breast cysts

The limited available research does not demonstrate that evening primrose oil has a significant effect on treating breast cysts.

Breast pain (mastalgia)

Although primrose oil is used for breast pain in several European countries, no high-quality human studies are published in this area. Therefore, the available information does not allow recommendation for or against the use of primrose oil in this condition.

Chronic fatigue syndrome/post-viral infection symptoms

Not enough information is available to advise the use of evening primrose oil for symptoms of chronic fatigue syndrome or fatigue following a viral infection.

Diabetes

A small number of laboratory studies and theory suggests that evening primrose oil may be helpful in diabetes, but more information is needed before a recommendation can be made.

Diabetic neuropathy (nerve damage)

Gamma-linolenic acid (GLA), one of the components of evening primrose oil, may be helpful in people with diabetic neuropathy. Additional studies are needed before a recommendation can be made.

Multiple sclerosis (MS)

It is theorized that primrose oil may be helpful in patients with MS based on laboratory studies. Limited evidence is available in humans, and a firm conclusion is not possible at this time.

Obesity/weight loss

Initial human study suggests that evening primrose oil may have no effects on weight loss.

Pre-eclampsia/high blood pressure of pregnancy

Evening primrose oil is proposed to have effects on chemicals in the blood called prostaglandins, which may play a role in pre-eclampsia. However, more studies are needed before a firm conclusion can be drawn.

Raynaud's phenomenon

Not enough scientific information is available to advise the use of evening primrose oil for Raynaud's phenomenon.

Rheumatoid arthritis

Benefits of evening primrose oil in the treatment of arthritis have not clearly been shown. More information is needed before a recommendation can be made.

Scale-like dry skin (ichthyosis vulgaris)

Early studies do not show a benefit from evening primrose oil. However, larger studies are needed to confirm this result.

Asthma

Small studies do not show evening primrose oil to be useful in the treatment of asthma. Further research is needed to confirm this conclusion.

Attention deficit hyperactivity disorder (ADHD)

Small human studies show no benefit from evening primrose oil in ADHD. Further research is needed to confirm this conclusion.

Cardiovascular health

Early study of evening primrose oil shows a lack of significant beneficial effects on cardiovascular function and health.

Menopause (flushing/bone metabolism)

Available studies do not show evening primrose oil to be helpful with these potential complications of menopause.

Pre-menstrual syndrome (PMS)

Small human studies do not report that evening primrose oil is helpful for the symptoms of PMS. A large, well-designed study is needed before any recommendation can be made.

Psoriasis

Initial research does not show a benefit from evening primrose oil in the treatment of psoriasis. However, studies have been small with design flaws, and many have combined primrose oil with other agents such as fish oil.

Schizophrenia

Results from studies of mixed quality do not support the use of evening primrose oil for schizophrenia.

Uses based on tradition or theory

The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Alcoholism, antioxidant, atherosclerosis, bruises (primrose oil applied to the skin), chemotherapy-induced neuropathy (nerve damage), Crohn's disease, cystic fibrosis, disorders of the stomach and intestines, fibroadenomas, hangover remedy, heart disease, hepatitis B, high cholesterol, hot flashes, inflammation, irritable bowel syndrome, kidney stones, melanoma, multiple sclerosis, pain, post-menopausal symptoms, post-natal depression, preventing preterm delivery, promoting easier birth, Sjögren's syndrome, skin conditions due to kidney failure in dialysis patients, systemic lupus erythematosus (SLE), ulcerative colitis, weight loss, whooping cough, wound healing (primrose oil poultice applied to the skin).

Dosing

The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.

Standardization

Standardization involves measuring the amount of certain chemicals in products to try to make different preparations similar to each other. It is not always known if the chemicals being measured are the "active" ingredients. Standardizedcapsules of evening primrose oil (EPO) may contain about 320 milligrams of linoleic acid (LA), 40 milligrams of gamma-linolenic acid (GLA), and 10 international units (IU) of vitamin E. Some preparations are labeled with percent content (70% LA, 9% GLA). LA from normal daily food intake provides approximately 250 to 1000 milligrams of GLA daily.

Adults (18 years and older)

Studies in the treatment of eczema or atopic dermatitis have used doses of 4 to 8 grams of evening primrose oil (EPO) daily, taken by mouth, divided into several smaller doses throughout the day. Studies of breast pain have used doses of 3 grams EPO daily, taken by mouth, divided into several smaller doses throughout the day.

Children (younger than 18 years)

Studies in children treated for skin conditions have used 3 grams of evening primrose oil daily, taken by mouth, divided into several smaller doses throughout the day. It is reported that the maximum dose should not be greater than 0.5 grams per kilogram of body weight daily.

About the Author

medlineplus.gov
MedlinePlus will direct you to information to help answer health questions. MedlinePlus brings together authoritative information from NLM, the National Institutes of Health (NIH), and other government agencies and health-related organizations. MedlinePlus also has extensive information about drugs, an illustrated medical encyclopedia, interactive patient tutorials, and latest health news.