Effects of genistein on hot flushes in early postmenopausal women: a randomized, double-blind EPT- and placebo-controlled study.

In Brief Objective: We evaluated and compared the effects of the phytoestrogen genistein, estrogen-progestogen therapy (EPT), and placebo on hot flushes and endometrial thickness in postmenopausal women. Design: Ninety healthy, postmenopausal women, 47 to 57 years of age, were randomly assigned to receive for 1 year continuous EPT (n = 30; 1 mg 17β-estradiol combined with 0.5 mg norethisterone acetate), the phytoestrogen genistein (n = 30; 54 mg/day), or placebo (n = 30). Endometrial safety was evaluated by intravaginal ultrasounds at baseline, 6 and 12 months. Results: By comparison with placebo, daily flushes reduced significantly by a mean of 22% (95% CI: −38 to −6.2; P < 0.01) after 3 months, by a mean of 29% (95% CI: −45 to −13; P < 0.001) after 6 months, and by a mean of 24% (95% CI: −43 to −5; P < 0.01) after 12 months of genistein treatment. Flush score decreased by a mean of 53% (95% CI: −79 to −26; P < 0.001) after 3 months, by a mean of 56% (95% CI: −83 to −28; P < 0.001) after 6 months, and by a mean of 54% (95% CI: −74 to −33; P < 0.001) after 12 months of EPT, as compared with placebo. No side effect was observed on the uterus of the participants. Conclusions: The present study confirms that genistein might have positive effects on hot flushes without a negative impact on endometrial thickness and suggests a future role of this phytoestrogen as a strategically therapeutic alternative in the management of postmenopausal symptoms. Healthy, postmenopausal women were randomly assigned to receive for 1 year continuous estrogen-progestin therapy, the phytoestrogen genistein, or placebo. By comparison with placebo, daily flushes reduced significantly by a mean of 22% after 3 months, by a mean of 29% after 6 months, and by a mean of 24% after 12 months of genistein treatment. No side effect was observed on the uterus of the participants. The study confirms that genistein has positive effects on hot flushes without a negative impact on endometrial thickness.