Part of Vis Clinics Functional, Naturopathic, and Environmental medicine model, Bio-Identical Hormone Replacement Therapy is a hormone replacement therapy that utilizes hormones, which are the same molecular structure as those naturally occurring in the body. These hormones may include natural progesterone, estrogens (estriol and estradiol), testosterone, and DHEA. The balance of these hormones is individualized for each man or woman and his or her symptoms.