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Evening Primrose Oil

Essential fatty acid seems to be the new nutritional buzzword. Amidst all this talk of good fat vs. bad fat, you may have come across evening primrose oil - a supplement that has shown some promise in easing the symptoms of rheumatoid arthritis, premenstrual syndrome, and eczema.  

How It Works 

Seeds of the Evening Primrose, a flower native to North America, have an unusual makeup of essential fatty acids. Approximately 70 percent is linoleic acid and about 10 percent is gamma-linolenic acid (GLA). Also known as an omega-6 fatty acid, GLA plays a role in the production of prostaglandins - hormone-like substances that influence inflammation and pain. Researchers believe evening primrose oil may be helpful for diseases that involve inflammation.

What It Might Do for You&

Although clinical trials have yielded mixed results, evening primrose oil seems to hold the most promise when it comes to relieving the nagging symptoms of eczema and PMS. Several double-blind, placebo-controlled studies have shown that the oil can relieve the itchy, red, scaly, dry skin associated with eczema as well as reduce patients' reliance on corticosteroid medicines, such as hydrocortisone cream. In regard to PMS, research has shown that the evening primrose oil could reduce breast tenderness and cyclical mood swings.

When it comes to rheumatoid arthritis, however, the evidence is not as conclusive. According to many studies, fish oil, a source of omega-3 essential fatty acids, seems to significantly improve symptoms of rheumatoid arthritis. A few studies suggest that evening primrose oil may also have some benefit. One double-blind study followed 56 people with rheumatoid arthritis for 6 months. Participants who received daily evening primrose oil supplements experienced significantly fewer symptoms than the placebo group. Nevertheless, many other studies found no benefit.

Potential Side Effects

No significant side effects have been reported.

Herb-Drug Interactions

If you decide to take evening primrose oil, talk it over with your healthcare provider as many drugs can interact with the supplement. For instance, evening primrose oil should not be consumed by those taking phenothiazine drugs since the combination may increase the risk of epileptic seizure. These drugs include:

  • Compazine (prochlorperazine)
  • Mellaril (thioridazine)
  • Sparine (promazine)
  • Stelazine (trifluoperazine)
  • Thorazine (chlorpromazine)
  • Trilafon (perphenazine)

Principal Author:

Stefanie Perelman, M.S., R.D., holds a B.A. in journalism from the University of Wisconsin-Madison and a master's in clinical dietetics from New York University. A registered dietitian, she presently works at Montefiore Medical Center in the Bronx and is available for private consultation.

Nutrition Editor

Donna Tinnerello MS, RD, CD/N is registered dietitian with more than 10 years experience in HIV and nutrition. She works in lower Manhattan at Cabrini Medical Center, the community and in private practice. Her subspecialties are cardiovascular, renal, gastrointestinal disease, diabetes and weight loss. Donna is available for private consultation by referral only.