What evening primrose and borage oils are: Evening primrose (Oenothera biennis), a yellow wildflower, yields an oil that is a popular supplement. Borage oil, a similar product, is derived from the seed of a plant (Borago officinalis) known variously as bee plant or starflower. The oil of both plants is rich in linoleic acid, an essential fatty acid. “Essential” means that the body needs it but does not produce it. Evening primrose oil also supplies another fatty acid, gamma-linolenic acid (GLA), which has many important functions in the body, such as controlling inflammation and helping the blood to clot.
Purported claims/benefits: Evening primrose and borage oils are said to be good for practically everything: eczema and nearly any kind of dermatitis or rash, rheumatoid arthritis, breast pain, breast cancer as well as other cancers, diabetes and the nerve damage it can cause, heart disease, symptoms of menopause, infertility, irritable bowel syndrome, hangovers, dry eye, premenstrual syndrome (PMS) and high cholesterol. Marketers claim you need more GLA than your body makes, that more is better and that certain diseases are caused by the lack of GLA.
What the research reveals
Evening primrose and borage oils and the fats they contain have been much studied. The great majority of studies, unfortunately, have been of poor quality, but a few have been well designed and have been published in peer-reviewed journals.
Evening primrose and borage oils are marketed to treat everything from cancer and arthritis to hot flashes and diabetes, though there’s no good clinical research to back up claims. They’re especially promoted for skin conditions, notably eczema.
Hot flashes and other menopausal symptoms. Two comprehensive reviews of research on herbal and other alternative treatments for menopausal symptoms (one in the Annals of Internal Medicine in 2002, the other in the Annals of Pharmacotherapy in 2004) found no benefit for evening primrose oil. The Natural Standard rated it as “D,” meaning there is “fair evidence against its use.” It has not been shown to be effective against PMS. In a 2010 study by researchers from the Mayo Clinic, women with premenstrual breast pain or tenderness who took evening primrose oil, vitamin E or both did not experience a statistically significant reduction in symptoms.
Rheumatoid arthritis. Some small studies have suggested benefits, but overall the evidence is inconsistent. However, a 2011 review of herbal therapies for rheumatoid arthritis by the Cochrane Collaboration concluded that evening primrose or borage oil may help reduce pain and improve function, but “adequate dose and duration of treatment are unknown.” The Arthritis Foundation and some doctors recommend evening primrose or borage oil on the “can’t-hurt-might-help” theory. If you have rheumatoid arthritis, talk with your doctor before you try it.
Breast cancer. A study in the International Journal of Cancer in 2000 found that GLA is a promising breast cancer therapy when combined with the drug tamoxifen. And lab research at Northwestern University found that GLA might be useful when used with another breast cancer drug. But these studies were very preliminary. Women with breast cancer should rely on proven treatments.
Diabetes and diabetic nerve damage. Some studies (mostly in the lab or in animals) suggest that evening primrose oil might be helpful. But a comprehensive review of studies in the Journal of the American Board of Family Practice in 2003 found that evening primrose oil (or similar supplements) is not effective for treating nerve damage caused by diabetes, and that drug interactions and side effects are possible.
Side effects: Potential side effects include stomach upset, nausea (less likely when take with food), rashes and headaches. Serious interactions can occur with certain anticlotting drugs. Borage oil, if not processed correctly, can contain substances that may be toxic to the liver over time. Some research suggests that the oils should not be used prior to having general anesthesia.
Bottom line: Evening primrose and borage oils are cheap, but an inexpensive supplement that does you no good and can cause side effects is not so cheap after all. And a real danger is that people with serious diseases will turn to evening primrose or borage oil instead of getting the medical treatment they need.
Originally published November 2012. Updated March 2014.