Objective: To evaluate the effects of a non-prescription red clover extract (MF11 RCE, Melbrosin International, Vienna, Austria) on selected sex hormones and endometrium in postmenopausal women.
Patients and methods: One-hundred and nine postmenopausal women with an age > or =40 years were randomly assigned to one of two groups either two capsules of MF11RCE (80mg isoflavone) per day for a 90 day period, or placebo of equal design. After a 7 day washout period, medication was crossed-over for another 90 days.
Results: Combined evaluation demonstrated that supplementation with MF11RCE (verum), in contrast to placebo, significantly increased plasma testosterone levels and decreased endometrial thickness.
Conclusion: MF11RCE exerts a moderate effect on testosterone levels in postmenopausal women, while estradiol levels remained unchanged. The observed reduction of endometrial thickness provides further support for a safe role for isoflavones in terms of endometrial hyperplasia.