Hormone receptors are very specific three-dimensional structures, designed to bind a particular hormone. Up till now, hormones available for patient treatment were modified chemically to give them a different structure. Unfortunately, these modifications had far-ranging effects on the way these hormones work. BHRT involves the use of human-identical hormones, or hormones with the EXACT molecular structure of the natural hormones they are meant to augment or replace. Use of bio-identical hormones allows a practitioner to replace or re-balance the patient's own hormones with ones that are identical to the original "real" hormones.