Japanese herb for hot flashes fails in U.S. trial

An herbal remedy widely used in Japan to ease menopause symptoms failed to show the same benefits in a clinical trial of U.S. women, researchers report.

The study looked at the effects of keishi-bukuryo-gan, a mix of cinnamon bark, peach pit and several other botanicals that is also known as known as TU-025.

Long used in traditional Japanese medicine, the herbal remedy is now regulated as a prescription drug in Japan, where gynecologists commonly recommend it for treating hot flashes and other symptoms of menopause.

So researchers were interested in whether benefits would be seen in U.S. women as well.

The authors randomly assigned 178 postmenopausal women to take either keishi-bukuryo-gan tablets or a placebo every day for three months. Tokyo-based Tsumura & Company provided the herb and partially funded the study.

In the end, the researchers found that while women on the herb saw improvements in hot flashes, sleep problems and other symptoms, so did women on the placebo.

And there was no clear advantage of the herbal product, the team reports in the journal Menopause.

Of women in the placebo group, hot flash frequency and severity dropped by a significant degree in 34 percent. The same was true of 40 percent of women taking a lower dose of keishi-bukuryo-gan (7.5 grams per day) and 38 percent using a higher dose (12.5 grams).

The differences among the three groups were not statistically meaningful, according to the researchers, led by Dr. Gregory A. Plotnikoff, who directs the Institute for Health and Healing at Abbott Northwestern Hospital in Minneapolis.

What's more, 20 percent of the women using keishi-bukuryo-gan reported diarrhea as a side effect. That was unexpected, Plotnikoff's team says. Plotnikoff did not respond to Reuters Health's requests for comment.

In Japan, a decade of post-marketing surveillance of the product has suggested that side effects are rare.

Of more than 700,000 women who've used the herbal remedy, an estimated 0.004 percent have had an "adverse event," Plotnikoff and his colleagues note in their report.

It's not clear why this trial of U.S. women failed to show the benefits that have been seen in Japanese women, according to the researchers.

But they point out that, in Japan, keishi-bukuryo-gan is used as part of the traditional medicine system known as Kampo, which considers each individual patient's "constitution."

Based on that system, the researchers note, keishi-bukuryo-gan is best for women who normally tend to feel cold (when they're not having hot flashes or night sweats), and are deemed to have stagnant qi (pronounced "chee"). Qi is a concept in traditional Chinese and Japanese medicine that refers to the flow of energy through the body.