Health Care Professional Information
Common Name
EPO, night willow herb, fever plant, king’s cure-all
Clinical Summary
Derived from the plant Oenothera biennis, evening primrose oil (EPO) is used for rheumatoid arthritis, premenstrual syndrome, eczema, fatigue, diabetic neuropathy and mastalgia. It contains gamma-linolenic acid (GLA), a primary fixed oil, which is converted to dihomo-gamma-linolenic-acid, a prostaglandin precursor (2) (3).
In vitro studies indicate that EPO may inhibit platelet aggregation (6) (7) but clinical data are inconsistent.
Small studies suggest its effectiveness against atopic dermatitis (18) and 5-azacitidine-induced skin reactions in patients with myelodysplastic syndromes (MLD) (19), and in preventing weight regain following extensive weight loss (5).
Conclusions from a meta analysis indicate utility of EPO in relieving symptoms of rheumatoid arthritis (21). Supplementation with vitamin E and EPO reduced cyclical mastalgia (20); however, a meta analysis showed that EPO is ineffective against mastalgia (1)and a systematic review suggests it may not be useful in alleviating premenstrual syndrome (22).
Evening primrose oil has not been studied extensively for cancer, but data from one study indicate that GLA may be an effective adjunctive therapy for breast cancer (4). More studies are needed.
Reduced seizure threshold has been reported with a combination of EPO and phenothiazine antipsychotics (9).
Although EPO does not have intrinsic estrogenic properties, some commercial products combine EPO with phytoestrogens. Therefore patients with hormone-sensitive cancer should use EPO products with caution.
Purported Uses
- Cancer treatment
- Diabetic neuropathy
- Eczema
- GI disorders
- High cholesterol
- Mastalgia
- Menopausal symptoms
- Premenstrual syndrome
- Rheumatoid arthritis
Constituents
- Fixed oils: Cis-Linoleic acid, cis-gammalinolenic acid (GLA), oleic acid, palmitic acid and stearic acid
(10)
Mechanism of Action
Theoretically, GLA can be converted directly to the prostaglandin, precursor dihomo-GLA. The administration of the oil might be beneficial to individuals unable to metabolize cis-linolenic acid to GLA and to produce subsequent intermediates of considerable metabolic significance, including prostaglandins.
(2) (3)
Pharmacokinetics
Repeated oral administration of evening primrose oil (480 mg/day gamma-linoleic acid/day) to healthy volunteers resulted in mean Cmax of approximately 20.7-22.6 mcg/ml. Gamma-linoleic acid levels were approximately 4.5 times greater from baseline in all patients, but serum levels of other fatty acids did not change significantly from baseline. Gastric absorption and Tmax for morning doses was longer than Tmax for identical doses given in the evening.
(11)
Contraindications
Pregnant women should not take evening primrose oil due to increased risk of pregnancy complications. (8)
Adverse Reactions
Reported: Headache, GI upset, nausea, and increased risk of pregnancy complications
Petechiae and ecchymoses were observed in a neonate whose mother used raspberry leaf tea and evening primrose oil (vaginally and orally) 1 week before childbirth.
(12)
Herb-Drug Interactions
Anticoagulants / Antiplatelets: May have additive effects and increase risk of bleeding.
Phenothiazines (e.g. fluphenazine): Evening primrose oil may lower the seizure threshold and precipitate seizures in patients taking phenothiazines.
(9)
Literature Summary and Critique
Srivastava A, et al. Evidence-based management of Mastalgia: a meta-analysis of randomised trials. Breast. Oct 2007;16(5):503-512.
In a meta-analysis of commonly used treatments for mastalgia, including Evening primrose oil (EPO), Bromocriptine, Danazol, and Tamoxifen, previously reported randomized, placebo-controlled trials were analyzed. Three randomized, controlled trials of EPO were included along with 1 trial of gamma-linolenic acid. Although Bromocriptine, Danazol, and Tamoxifen improved mastalgia, EPO was ineffective and therefore should not be used for mastalgia relief.
Dosage (Inside MSKCC Only)
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References
- Srivastava A, Mansel RE, Arvind N, et al. Evidence-based management of Mastalgia: a meta-analysis of randomised trials. Breast. Oct 2007;16(5):503-512.
- Belch JJ, Hill A. Evening primrose oil and borage oil in rheumatologic conditions. Am J Clin Nutr 2000;71:352S-6S.
- Tyler, V. Herbs of Choice, the Therapeutical Use of Phytomedicinals. Binghamton: Pharmaceutical Press; 1994.
- Kenny FS, et al. Gamma linolenic acid with Tamoxifen as primary therapy in breast cancer. Int J Cancer 2000; 85:643-8.
- Schirmer MA, Phinney SD. Gamma-linolenate reduces weight regain in formerly obese humans. J Nutr. Jun 2007;137(6):1430-1435.
- De La Cruz JP, Martin-Romero M, Carmona JA, et al. Effect of evening primrose oil on platelet aggregation in rabbits fed an atherogenic diet. Thromb Res. Jul 1 1997;87(1):141-149.
- Guivernau M, Meza N, Barja P, Roman O. Clinical and experimental study on the long-term effect of dietary gamma-linolenic acid on plasma lipids, platelet aggregation, thromboxane formation, and prostacyclin production. Prostaglandins Leukot Essent Fatty Acids. Nov 1994;51(5):311-316.
- Dove D, Johnson P. Oral evening primrose oil: its effect on length of pregnancy and selected intrapartum outcomes in low-risk nulliparous women. J Nurse Midwifery. 1999 May-Jun;44(3):320-4.
- Holman CP, et al. A trial of evening primrose oil in the treatment of chronic schizophrenia. J Orthomolecular Psychiatry 1983;12:302-4.
- Newall C. Herbal Medicines, A Guide for Health Care Professionals. London: Pharmaceutical Press; 1997.
- Martens-Lobenhoffer J, Meyer FP. Pharmacokinetic data of gamma-linoleic acid in healthy volunteers after the administration of evening primrose oil (Epogam). Int J Clin Pharmacology Therapeutics 1998;36:363-6.
- Wedig KE, Whitsett JA. Down the primrose path: petechiae in a neonate exposed to herbal remedy for parturition. J Pediatr. Jan 2008;152(1):140, 140 e141.
- Zurier RB, et al. Gamma-linolenic acid treatment of rheumatoid arthritis. A randomized, placebo-controlled trial. Arthritis Rheum 1996;39:1808-17.
- Budeiri D, et al. Is evening primrose oil of value in the treatment of premenstrual syndrome? Control Clin Trials 1996;17:60-8.
- Keen H, et al. Treatment of diabetic neuropathy with gamma-linolenic acid. Diabetes Care 1993;16:8-15.
- Pye JK, et al. Clinical experience of drug treatment for mastalgia. Lancet 1985;2:373-7.
- Blommers J, et al. Evening primrose oil and fish oil for severe chronic astalgia: a randomized, double-blind, controlled trial. Am J Obstet Gynecol. 2002 Nov;187(5):1389-94.
- Senapati S, Banerjee S, Gangopadhyay DN. Evening primrose oil is effective in atopic dermatitis: a randomized placebo-controlled trial. Indian J Dermatol Venereol Leprol. 2008 Sep-Oct;74(5):447-52.
- Platzbecker U, Aul C, Ehninger G, Giagounidis A. Reduction of 5-azacitidine induced skin reactions in MDS patients with evening primrose oil. Ann Hematol. 2009 Aug 28. [Epub ahead of print]
- Pruthi S, Wahner-Roedler DL, Torkelson CJ, et al. Vitamin E and evening primrose oil for management of cyclical mastalgia: a randomized pilot study. Altern Med Rev. 2010 Apr;15(1):59-67.
-
- Dante G, Facchinetti F. Herbal treatments for alleviating premenstrual symptoms: a systematic review. Journal of psychosomatic obstetrics and gynaecology. 2011 Mar;32(1):42-51.
Consumer Information
How It Works
Bottom Line: Evening primrose oil has not been shown to treat or prevent cancer.
Scientists have not figured out how exactly evening primrose oil exerts its effects, but theorize that it has anti-inflammatory activity. It may be beneficial for patients with mastalgia (breast pain). It may also help those with diabetes, heart disease, cancer, premenstrual syndrome, eczema, or high cholesterol but there is not enough data to support such effects.
Purported Uses
- To treat cancer
Evening primrose oil had no effect on tumor size or survival in patients with liver cancer. In another study, patients with breast cancer who received GLA in addition to Tamoxifen had faster response to treatment than those who received Tamoxifen alone.
- To treat diabetic neuropathy
Studies in animals suggest that evening primrose oil can prevent or reverse diabetic neuropathy, and one clinical trial almost 20 years ago supported this use. However, more research is needed.
- To treat eczema
Clinical trials show conflicting results.
- To treat gastrointestinal disorders such as colitis or irritable bowel syndrome
One clinical trial has studied the effects of evening primrose oil on ulcerative colitis, showing weak effects. In general, there is little support for this use.
- To reduce high cholesterol
One small clinical trial suggested that evening primrose oil led to a decrease in LDL (“bad”) cholesterol, but these findings have not been confirmed by additional studies.
- To relieve breast pain (mastalgia)
A handful of clinical trials support this use, especially for mastalgia associated with menstrual cycle.
- To relieve menopausal symptoms
One clinical trial found that evening primrose oil was no better than placebo at relieving menopausal hot flashes.
- To prevent premenstrual syndrome (PMS)
Results of clinical trials are inconsistent.
- To reduce inflammation of rheumatoid arthritis
Clinical studies show that evening primrose rose oil may be useful in reducing symptoms of RA.
Research Evidence
Mastalgia (breast pain):
The results of several clinical trials and volunteer studies conducted in the United Kingdom were compiled to measure the effect of evening primrose oil on mastalgia (breast pain). Overall, evening primrose oil was found to have a similar level of effectiveness as bromocriptine (a drug used to treat mastalgia), having beneficial effects in 44% of women treated. However, this was less effective than treatment with danazol, another medication. Treatment with evening primrose oil was more effective in women with cyclical mastalgia than in women with non-cyclical pain. Another study found evening primrose oil no more effective than wheat-germ oil in the treatment of breast pain.
Do Not Take If
- You are pregnant.
- You are taking anticoagulants or antiplatelet agents (Evening primrose oil may enhance their effects.)
- You are taking phenothiazines such as fluphenazine (Evening primrose oil may lower the seizure threshold and increase the risk of seizures in patients taking phenothiazines).
Last updated: June 4, 2012
acid (A-sid)
A chemical that gives off hydrogen ions in water and forms salts by combining with certain metals. Acids have a sour taste and turn certain dyes red. Some acids made by the body, such as gastric acid, can help organs work the way they should. An example of an acid is hydrochloric acid. Acidity is measured on a scale called the pH scale. On this scale, a value of 7 is neutral, and a pH value of less than 7 to 0 shows increasing acidity.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)adjunctive therapy (A-junk-tiv THAYR-uh-pee)
Another treatment used together with the primary treatment. Its purpose is to assist the primary treatment. Also called adjunct therapy.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)analysis (uh-NA-lih-sis)
A process in which anything complex is separated into simple or less complex parts.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)anti-inflammatory (AN-tee-in-FLA-muh-TOR-ee)
Having to do with reducing inflammation.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)arthritis (ar-THRY-tis)
A disease that causes inflammation and pain in the joints.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)breast (brest)
Glandular organ located on the chest. The breast is made up of connective tissue, fat, and breast tissue that contains the glands that can make milk. Also called mammary gland.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)breast cancer (brest KAN-ser)
Cancer that forms in tissues of the breast, usually the ducts (tubes that carry milk to the nipple) and lobules (glands that make milk). It occurs in both men and women, although male breast cancer is rare.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)cancer (KAN-ser)
A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Cancer cells can also spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is a cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is a cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is a cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord. Also called malignancy.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)cholesterol (koh-LES-teh-rol)
A waxy, fat-like substance made in the liver, and found in the blood and in all cells of the body. Cholesterol is important for good health and is needed for making cell walls, tissues, hormones, vitamin D, and bile acid. Cholesterol also comes from eating foods taken from animals such as egg yolks, meat, and whole-milk dairy products. Too much cholesterol in the blood may build up in blood vessel walls, block blood flow to tissues and organs, and increase the risk of developing heart disease and stroke.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)clinical (KLIH-nih-kul)
Having to do with the examination and treatment of patients.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)clinical trial (KLIH-nih-kul TRY-ul)
A type of research study that tests how well new medical approaches work in people. These studies test new methods of screening, prevention, diagnosis, or treatment of a disease. Also called clinical study.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)colitis (koh-LY-tis)
Inflammation of the colon.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)danazol (DA-nuh-zole)
A synthetic hormone that is a type of androgen and is used to treat endometriosis. It is being evaluated in the treatment of endometrial cancer.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)dermatitis (DER-muh-TY-tis)
Inflammation of the skin.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)diabetes (dy-uh-BEE-teez)
Any of several diseases in which the kidneys make a large amount of urine. Diabetes usually refers to diabetes mellitus in which there is also a high level of glucose (a type of sugar) in the blood because the body does not make enough insulin or use it the way it should.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)drug (drug)
Any substance, other than food, that is used to prevent, diagnose, treat or relieve symptoms of a disease or abnormal condition. Also refers to a substance that alters mood or body function, or that can be habit-forming or addictive, especially a narcotic.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)eczema (EK-zeh-muh)
A group of conditions in which the skin becomes inflamed, forms blisters, and becomes crusty, thick, and scaly. Eczema causes burning and itching, and may occur over a long period of time. Atopic dermatitis is the most common type of eczema.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)GI
Refers to the stomach and intestines. Also called gastrointestinal.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)herbal (ER-bul)
Having to do with plants.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)in vitro (in VEE-troh)
In the laboratory (outside the body). The opposite of in vivo (in the body).
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)liver (LIH-ver)
A large organ located in the upper abdomen. The liver cleanses the blood and aids in digestion by secreting bile.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)medication (MEH-dih-KAY-shun)
A legal drug that is used to prevent, treat, or relieve symptoms of a disease or abnormal condition.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)menstrual cycle (MEN-stroo-ul SY-kul)
The monthly cycle of hormonal changes from the beginning of one menstrual period to the beginning of the next.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)meta-analysis (meh-tuh-uh-NA-lih-sis)
A process that analyzes data from different studies done about the same subject. The results of a meta-analysis are usually stronger than the results of any study by itself.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)myelodysplastic syndromes (MY-eh-loh-dis-PLAS-tik SIN-dromz)
A group of diseases in which the bone marrow does not make enough healthy blood cells. Also called preleukemia and smoldering leukemia.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)neuropathy (noor-AH-puh-thee)
A nerve problem that causes pain, numbness, tingling, swelling, or muscle weakness in different parts of the body. It usually begins in the hands or feet and gets worse over time. Neuropathy may be caused by physical injury, infection, toxic substances, disease (such as cancer, diabetes, kidney failure, or malnutrition), or drugs, including anticancer drugs. Also called peripheral neuropathy.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)phenothiazine (FEE-noh-THY-uh-zeen)
A type of drug that is used to treat severe mental and emotional disorders, severe nausea and vomiting, and certain other conditions. It belongs to the families of drugs called antipsychotics and antiemetics.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)placebo (pluh-SEE-boh)
An inactive substance or treatment that looks the same as, and is given the same way as, an active drug or treatment being tested. The effects of the active drug or treatment are compared to the effects of the placebo.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)placebo-controlled (pluh-SEE-boh-kun-TROLD)
Refers to a clinical study in which the control patients receive a placebo.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)platelet (PLAYT-let)
A tiny piece of a cell found in the blood that breaks off from a large cell found in the bone marrow. Platelets help wounds heal and prevent bleeding by forming blood clots. Also called thrombocyte.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)pregnancy (PREG-nun-see)
The condition between conception (fertilization of an egg by a sperm) and birth, during which the fertilized egg develops in the uterus. In humans, pregnancy lasts about 288 days.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)randomized
Describes an experiment or clinical trial in which animal or human subjects are assigned by chance to separate groups that compare different treatments.
(http://www.cancer.gov/dictionary)response (reh-SPONTS)
In medicine, an improvement related to treatment.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)seizure (SEE-zher)
Sudden, uncontrolled body movements and changes in behavior that occur because of abnormal electrical activity in the brain. Symptoms include loss of awareness, changes in emotion, loss of muscle control, and shaking. Seizures may be caused by drugs, high fevers, head injuries, and certain diseases, such as epilepsy.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)stomach (STUH-muk)
An organ that is part of the digestive system. The stomach helps digest food by mixing it with digestive juices and churning it into a thin liquid.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)supplementation (SUH-pleh-men-TAY-shun)
Adding nutrients to the diet.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)syndrome (SIN-drome)
A set of symptoms or conditions that occur together and suggest the presence of a certain disease or an increased chance of developing the disease.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)tamoxifen (tuh-MOK-sih-FEN)
A drug used to treat certain types of breast cancer in women and men. It is also used to prevent breast cancer in women who have had ductal carcinoma in situ (abnormal cells in the ducts of the breast) and in women who are at a high risk of developing breast cancer. Tamoxifen is also being studied in the treatment of other types of cancer. It blocks the effects of the hormone estrogen in the breast. Tamoxifen is a type of antiestrogen. Also called tamoxifen citrate.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)tumor (TOO-mer)
An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancer), or malignant (cancer). Also called neoplasm.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)vitamin (VY-tuh-min)
A nutrient that the body needs in small amounts to function and stay healthy. Sources of vitamins are plant and animal food products and dietary supplements. Some vitamins are made in the human body from food products. Vitamins are either fat-soluble (can dissolve in fats and oils) or water-soluble (can dissolve in water). Excess fat-soluble vitamins are stored in the body’s fatty tissue, but excess water-soluble vitamins are removed in the urine. Examples are vitamin A, vitamin C, and vitamin E.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)
