Red clover is a plant that contains isoflavones, substances that have an estrogen-like effect and that may reduce levels of natural estrogen in the body. Red clover is most often used to treat menopausal symptoms (University of Maryland), but it has also demonstrated some benefits in males regarding prostate health.
In a study conducted in China, scientists used red clover isoflavones to treat four samples of human benign prostatic hyperplasia cells at different concentrations and four samples with different concentrations of finasteride. The red clover isoflavones inhibited the proliferation of the BPH cells at significantly greater levels than did a control sample, but it did not perform as well as finasteride. Red clover also induced apoptosis of the prostate cells by about 18 percent, which was significantly different than control. (Chen 2010)
An earlier study, conducted in Australia, involved 38 men who had prostate cancer. Before undergoing radical prostatectomy, 20 men consumed 160 mg/day of red clover-derived isoflavones (18 completed the study), and 18 men served as controls. Among the isoflavone-treated men, apoptosis in prostatectomy specimens were significantly higher than in controls, specifically in areas of low to moderate grade cancer. The study’s authors suggested that dietary isoflavones may stop the progression of prostate cancer by inducing apoptosis in low to moderate-grade tumors. (Jarred 2002)
The impact of an isoflavonoid extract from red clover on the prostate, sexual function, liver function, and quality of life in men who had an elevated PSA level and negative prostate biopsy results was evaluated during a one-year treatment study. Twenty men took 60 mg of an isoflavone extract daily for one year. The average PSA level was 10.16 ng/mL at the start of the study and 7.15 ng/mL after one year (a decrease of 33%), and the average prostate volume decreased slightly. Sex hormone levels did not change, and there also was no change in sexual function. Liver transaminases also increased significantly, which may indicate liver inflammation or damage. (Engelhardt 2008)
Chen MY et al. Red clover isoflavones inhibit the proliferation and promote the apoptosis of benign prostatic hyperplasia stromal cells. Zhonghua Nan Ke Xue 2010 Jan; 16(1): 34-39
Engelhardt PF, Riedl CR. Effects of one-year treatment with isoflavone extract from red clover on prostate, liver function, sexual function, and quality of life in men with elevated PSA levels and negative prostate biopsy findings. Urology 2008 Feb; 71(2): 185-90
Jarred RA et al. Induction of apoptosis in low to moderate-grade human prostate carcinoma by red clover-derived dietary isoflavones. Cancer Epidemiol Biomarkers Prev 2002 Dec; 11(12): 1689-96