The Physiologic Role and Use of Estriol.

Obtaining estrogen balance with a physiologic estriol and estradiol ratio is an important aspect of physiologic bioidentical hormone restoration therapy. Risks, including that of breast cancer, should be minimized while attempting to obtain the protective benefits and symptom management with therapy. Estriol plays a central role in protecting against breast cancer and should be considered an integral part of therapy for any patient with lower than normal physiologic levels.