Researchers at the University of Miami are to carry out a trial testing the safety and effectiveness of an herbal pill designed to treat the symptoms of menopause, reports the Miami Herald.
The pill contains black cohosh, isoflavones and kava kava, the herb which has been recalled in some European countries, including Ireland, Switzerland and Britain, for its link to liver damage.
The Food and Drug Administration (FDA) is also investigating the dangers associated with kava kava, although FDA scientists cannot yet say if the blockbuster seller is to blame for a recent case in the US which led to a liver transplant.
"The jury's still out on kava," said Mark Blumenthal of the American Botanical Council, which has joined industry groups in the investigation. However the FDA has noted that there has been misuse of the supplement and Blumenthal agrees that people with liver problems should not take the product.
The Miami University researchers maintain that previous cases of liver damage in Europe involved an excessive use of kava kava, often 100 times the recommended daily dose of 50 milligrams. In addition, the people were combining the kava kava with other drugs or supplements.
''It's relatively safe at low levels, and it's effective,'' leading investigator Dr Perry said about kava kava. "I'm very wary of supplements that are many times the recommended levels. Some people think a little is good and much more is better, and that is not necessarily true.''
Around 250 women will be involved in the trial, which will be double-blind and randomised. Neither researchers nor participants will know who has received the pill and who has received a placebo.
''It's the purest scientific study; it ferrets out bias,'' said assistant professor of gynaecology at University of Miami Dr. Wayne Whitted, who will assist with the four-month study to begin in April.
Whitted said such a study was long overdue. ''I think many, if not most, women have tried some sort of alternative product, but they really have not been studied in a scientific way that shows whether the product can assist women.''
The study is to be funded by a supplement maker who cannot be named in case it compromises the blind nature of the research.
''Some of the ingredients have been investigated independently and have been shown to be effective,'' Perry said. "However, the combination of ingredients has not been looked at together and that's the beauty of it."
Perry added that ''the ingredients are in amounts that have been shown to be safe,'' highlighting one of the key concerns over unregulated supplements.
Sales of herbs and supplements designed to reduce menopausal symptoms have increased by 200 per cent in the US since 1998, according to market research firms Spins and ACNielsen.