Menopause and Hot Flashes and Evening Primrose Oil--Does It Work?

Numerous studies have been conducted concerning alternative treatments for menopause and hot flashes, and evening primrose is one of the natural products that have been studied. According to surveys, control of hot flashes is the number one reason that women seek treatment during the years leading up to and following menopause.

Because so much scientific research has been conducted concerning the safety and effectiveness of non-hormonal treatments for control of hot flashes, several research groups have gone to the effort of compiling the published data. You might call these the "studies of the studies". You might wonder why all of this is necessary. There are several reasons, but the primary one is that hot flashes respond to placebo. The majority of studies confirm that women taking placebo experience about a 20% reduction in hot flash symptoms. So, researchers interested in promoting a specific product can honestly say things like "women using product X reported a reduction in hot flash symptoms."

A recent search for studies published at Pub Med, a service of the National Library of Medicine and the National Institutes of Health, concerning menopause and hot flashes and evening primrose returned 20 results. Evening primrose oil is claimed to provide a variety of health benefits, including the control of hot flashes, but finding contemporary medical literature to support these claims is difficult.

In 1994, researchers at the Keele University in England enrolled 56 menopausal women suffering from hot flashes at least three times a day to complete a six month study of the effectiveness of evening primrose for control of hot flashes. Only 35 women completed the study. 18 of them took 500 mg of evening primrose oil with 10 mg of vitamin E twice a day, while 17 took a placebo. After analyzing the dairies of the participants, researchers concluded that evening primrose offered no benefit over placebo in treating menopausal hot flashes. On the average, the women taking placebo experienced 0.7 less hot flashes per day, while women taking evening primrose experienced 0.5 less per day.

One of the "studies of the studies" was completed in 2002 by researchers at Columbia University in New York. These researchers used a number of different sources to accumulate information relating to menopause and hot flashes, and evening primrose was again mentioned. In total the researchers selected 58 different studies that were randomized, placebo-controlled clinical trials. They came to the following conclusions. Dong quai, evening primrose oil, vitamin E and acupuncture do not affect hot flashes.

On the other hand, the researchers believed that black cohosh showed promise for the control of hot flashes, but they were wary to recommend it, because safety data concerning the herb had not been accumulated at that time. Since then, studies have shown that black cohosh has no negative side effects and has no estrogen like affects on breast or uterine cancer cell lines. Black cohosh is currently recommended by most practitioners, whereas evening primrose is not believed to be effective. For more information about menopause and hot flashes, and evening primrose and black cohosh, please visit the Menopause and PMS Guide.