There is no strong evidence either way for several herbal remedies commonly taken to relieve troublesome menopausal symptoms. And for some, there is hardly any evidence at all.
Between 30 percent and 70 percent of women in industrialized countries will experience vasomotor symptoms around menopause, such as hot flushes and night sweats, prompted by the sharp fall in estrogen levels.
On average, such symptoms last for around four years, but in around one in 10 women, they can last more than 12 years.
Herbal remedies commonly used to relieve menopausal symptoms include black cohosh, red clover, Dong quai, evening primrose oil, and ginseng. Others include wild yam extract, chaste tree, hops, sage leaf, and kava kava.
The research is published in the January issue of the Drug and Therapeutics Bulletin (DTB).
But little good quality evidence on the effectiveness of herbal medicines, or how they might react with prescription medicines is available, says DTB.
And, in general, safety has been under-researched, which is a major concern given that herbal remedies are often assumed to be “safe” just on the grounds that they are “natural,” says DTB.
Published studies are often poorly designed, include too few participants, or don’t last long enough to be of real value.
Furthermore, the chemical makeup of various preparations of the same herb may differ, which can make it difficult to compare trial results.
The drugs regulator, the Medicines and Healthcare products Regulatory Agency (MHRA), has given a Traditional Herbal Registration to Menoherb, which contains black cohosh, under a scheme designed to boost the safety of herbal products on sale.
But clinical trial data on black cohosh are “equivocal,” says DTB, with some studies suggesting that the remedy works well, while others suggest that it does not relieve symptoms effectively.
Liver toxicity is also a potential side effect of black cohosh.
There is “no convincing evidence” that red clover extract is effective, says DTB, and little evidence one way or another for dong quai, evening primrose oil, wild yam, chaste tree, hops, or sage.
Source: British Medical Association