Evening primrose has served as both food and medicine at previous times 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.
Today, evening primrose seed oil (EPO) is used primarily to relieve the itchiness associated with certain skin conditions (such as eczema) and to ease breast tenderness from premenstrual syndrome (PMS) or other causes. It is considered to be potentially useful for the treatment of many conditions including:
- Allergies, particularly skin rash or hives
- Eczema, including redness and scaling in addition to itching
- PMS, including mood swings and bloating in addition to breast tenderness
- Arthritis, primarily rheumatoid
- Dry eyes, from, for example, Sjogren's syndrome (a condition with symptoms of dry eyes, dry mouth, and, often, arthritis)
- Peripheral Neuropathy, a nerve condition experienced as numbness, tingling, pain, burning, or lack of sensation in the feet and/or legs, from Diabetes
- Menopausal symptoms. Although EPO has gained some popularity for treating hot flashes, the research to date has not confirmed that GLA or EPO is beneficial for these symptoms. With that said, there are individual women who report improvement; therefore, it may be worthwhile to talk to your doctor about whether it is safe for you to try EPO or another form of GLA supplements to alleviate hot flashes.
- Weight loss, particularly if you have a family history of obesity
- Alcoholism; EPO may help lessen cravings for alcohol and prevent liver damage. More research is needed in this area.
Other conditions for which EPO is currently under scientific investigation and may prove beneficial include breast cancer, heart disease, high cholesterol, attention deficit/hyperactivity disorder, stomach ulcers, and inflammatory bowel disease (such as ulcerative colitis). While some test tube and animal studies seem promising, it is much too early to tell if EPO is helpful or harmful for these conditions.
Another condition for which a proprietary herbal product has gained popularity is cellulite. The product combines EPO with several different herbs including ginkgo, sweet clover, sea-weed, grape seed oil, and lecithin. A recent study of this product, however, found that it is no more effective than placebo in getting rid of cellulite.
The main active ingredient in EPO is an omega-6 fatty acid known as gamma-linolenic acid (GLA). See What's It Made Of? for a brief description of GLA. Also, please see the monograph on the supplement GLA for detailed information about the science supporting the uses mentioned and other potential uses for GLA and EPO.
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 (which means that the leaves grow on both sides of the stem at alternating levels). This monograph focuses on the seed from which the oil is extracted.
What's It Made Of?
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. There are differences, though, between the different types of omega-6 fatty acids in terms of whether they are healthy or unhealthy. Please see the monograph on the supplement omega-6 fatty acids for a detailed description of these essential fatty acids, including the effects they have on the body and how to balance them in your diet.
Other sources of GLA include borage and black currant oils.
EPO is available as oil or in capsules (the preferred form). EPO products should be kept in the refrigerator and out of direct sunlight to prevent the oil from becoming rancid.
Generally, high-quality oil will be certified as organic by a reputable third party, packaged in light-resistant containers, refrigerated, and marked with a freshness date.
EPO is usually standardized to contain 8% gamma-linolenic acid.
How to Take It
The use of herbs is a time-honored approach to strengthening the body and treating disease. Herbs, however, contain active substances that can trigger side effects and that can interact with other herbs, supplements, or medications. For these reasons, herbs should be taken with care, under the supervision of a practitioner knowledgeable in the field of botanical medicine.
For skin rash, the recommended total daily dosage for children is 2 to 4 grams (in capsule form).
- Skin rash: the recommended daily dosage is 6 to 8 grams for adults.
- Mastalgia (breast pain): the recommended dosage is 3 to 4 grams daily.
- PMS: the recommended dosage is 3 grams daily.
- Arthritis: a dosage of about 3 grams per day is considered safe.
The American Herbal Products Association (AHPA) gives EPO a class 1 safety rating, which indicates that it is safe with appropriate use. Reported side effects are rare and mild, and include nausea, stomach pain, and headache. Stomach pain and loose stools may be indications that the dosage is too high.
Omega-6 supplements, including GLA and EPO, should not be used if you have a seizure disorder because there have been reports of these supplements inducing seizures.
Taking EPO while breastfeeding is considered safe as breast milk actually contains both LA and GLA. Borage oil, and possibly other substances containing GLA, should not be used during pregnancy because they may be harmful to the fetus and induce early labor.
If you are currently being treated with any of the following medications, you should not use EPO without first talking to your healthcare provider.
Ceftazidime, an antibiotic
GLA from EPO or other sources may increase the effectiveness of ceftazidime, an antibiotic in a class known as cephalosporins, against a variety of bacterial infections.
Chemotherapy for cancer
GLA from EPO or other sources may increase the effects of anti-cancer treatments, such as doxorubicin, cisplatin, carboplatin, idarubicin, mitoxantrone, tamoxifen, vincristine, and vinblastine.
In animal studies, EPO administered during treatment with cyclosporine, a medication used to suppress immune function after an organ transplant, for example, may protect against kidney damage (a possible side effect of the medication).
Nonsteroidal Anti-inflammatory Drugs (NSAIDs)
Theoretically, use of NSAIDs, such as ibuprofen, together with borage oil or other GLA containing supplements like EPO may counter-act the effects of the supplement. Research in this area is needed to know if this theory is accurate.
Phenothizines for Schizophrenia
Individuals taking a class of medications called phenothiazines (such as chlorpromazine, fluphenazine, perphenazine, promazine, and thioridazine) to treat schizophrenia should not take EPO because it may interact with these medications and increase the risk of seizures.
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Review Date: April 2002 Reviewed By: Participants in the review process include: Jacqueline A. Hart, MD, Department of Internal Medicine, Newton-Wellesley Hospital, Harvard University and Senior Medical Editor Integrative Medicine, Boston, MA; Dahlia Hirsch, MD (April 1999), Center for Holistic Healing, BelAir, MD; Gary Kracoff, RPh (Pediatric Dosing section February 2001), Johnson Drugs, Natick, MA; Steven Ottariono, RPh, Veteran's Administrative Hospital, Londonderry, NH; David Winston, Herbalist (April 1999), Herbalist and Alchemist, Inc., Washington, NJ; Tom Wolfe, P.AHG (April 1999), Smile Herb Shop, College Park, MD. All interaction sections have also been reviewed by a team of experts including Joseph Lamb, MD (July 2000), The Integrative Medicine Works, Alexandria, VA;Enrico Liva, ND, RPh (August 2000), Vital Nutrients, Middletown, CT; Brian T Sanderoff, PD, BS in Pharmacy (March 2000), Clinical Assistant Professor, University of Maryland School of Pharmacy; President, Your Prescription for Health, Owings Mills, MD; R. Lynn Shumake, PD (March 2000), Director, Alternative Medicine Apothecary, Blue Mountain Apothecary & Healing Arts, University of Maryland Medical Center, Glenwood, MD; Ira Zunin, MD, MPH, MBA (July 2000), President and Chairman, Hawaii State Consortium for Integrative Medicine, Honolulu, HI.
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