Objective: Red clover (Trifolium pratense) extracts are becoming increasingly popular, primarily for the treatment of menopausal symptoms. Although promoted as a phytoestrogen source similar to soybeans, red clover is a medicinal herb, not a food, and traditionally has not been used long-term. We sought to review the scientific literature for this newer use.
Design: Medline was searched for controlled trials of red clover (Trifolium pratense), and other sources were searched for other studies and abstracts.
Results: Two double-blind placebo-controlled trials found no beneficial effects of red clover extracts on hot flashes or other menopausal symptoms. Three of four trials examining the effect of red clover on lipids found no benefit; the fourth trial contains too little data to interpret. One study examining the effect of red clover on arterial compliance found a significant beneficial effect on arterial compliance.
Conclusion: Red clover extracts have as yet no clear demonstrable benefit for menopausal symptoms. Potential estrogenic effects on breast and endometrium have not been adequately assessed. The presence of coumarins in some clover species makes it imperative to include tests of clotting factors in future trials.