Different estrogens combined with various synthetic progesterones are used in hormone therapy for postmenopausal women. All these compounds, which do not have the same chemical structure and the same pharmacokinetic behavior as the bioidentical hormones (estradiol and progesterone) have properties which can lead to differences in therapeutic results. Recent biological and clinical data strongly suggest that the heart disease and blood clot risks as well as the breast cancer risk attributed to conventional hormone therapy use would not be the same as when using bioidentical hormones.