Susan Merenstein, Pharmacist/Owner

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What Are Bioidenticals Hormones and Are They Safe For Your Patients?

What Are Bioidentical Hormones?

The term bioidentical does not indicate the source of the hormone but rather the chemical structure. Bioidentical hormones are originally derived from a molecule called diosgenin in either soy or yam. Through a series of chemical processes first developed in 1942, the plant molecule, which is structurally similar to a steroid hormone, is converted to a specific hormone molecule that is an exact match to human endogenous hormones. There is no difference between bioidentical hormones and endogenous hormones in structure or function. This is critical because the molecular structure is what determines the function and activity of the hormone. This is why when you prescribe bioidentical hormones you can be assured that they convey the same action and effect, are metabolized into the same downstream metabolites, have same binding affinity, and are expected to restore normal physiology. Confusion about different types of HRT is due to the lack of clear distinction between the molecular formulas and the lack of focus on their significantly different effects in the body.1, 2, 3, 4

“All hormones are not the same and have different actions, which must be distinguished and described accordingly.”

Are Non-Bioidentical Hormones Really That Different from Bioidentical Hormones?

Absolutely! Since there is a molecular difference between non-biologically identical hormones and biologically identical hormones, they have different effects. Bioidentical hormones do not have the same risk profile especially in regard to cardiovascular, clotting, and breast cancer risk factors.

To be clear, even though a non-bioidentical hormone may mimic some of the endogenous hormone actions, that does not make it the same in structure or function. Non-bioidentical hormones interfere with normal physiological processes and can lead to adverse events otherwise known as side effects or increased risk of issues. For example, Progesterone is a pregnancy class B drug, that supports pregnancy and prevents miscarriage. Medroxyprogesterone acetate is a pregnancy class X drug, used in the morning after pill, known to cause birth defects. To view the difference in the different molecular structures, see the chart below.

Bioidentical HRT (BHRT)

Bioidentical HRT often referred to as BHRT, is a prescription modality for hormone replacement and hormone balancing for treating the signs and symptoms of PMS, perimenopause, menopause as well as post-menopausal issues. Prescriptions for bioidentical hormones are available from compounding or conventional pharmacies in cream, pill, patches, or pellets and typically administered after assessing history, symptoms, a physical or gynecological exam, review of lab work, and then monitored appropriately by practitioners trained in BHRT.

Are Bioidentical Hormones Safe?

Twenty-five years of research and hundreds of published studies conducted in the US and Europe have demonstrated bioidentical hormones to be equally or more effective than non-bioidentical hormones for symptoms. Published studies also show their safety. In the January 2009 issue of Postgraduate Medicine, Dr. Kent Holtorf, published an article citing 196 research studies. He comments, “Physiological data and clinical outcomes demonstrate that bio-identical hormones are asso­ciated with lower risks, including the risk of breast cancer, cardio­vascular disease, and are more efficacious than their synthetic and animal derived counterparts. Until evidence is found to the contrary, bioidentical hormones remain the preferred method of hormone replacement therapy.” 5


1 Mueck A, Seeger H, Wallwiener D. Comparison of the proliferative effects of estradiol and conjugated equine estrogens on human breast cancer cells and impact of continuous combined progestogen addition. Climacteric. 2003; 6:221-227.

2 Lippert T, Seeger H, Mueck A. Pharmacology and toxicology of different estrogens. G Endodonzia. 2001; 15:26-33.

3 Schindler A, Campagnoli C, Druckman R, et al. Classification and pharmacology of progestins.

Maturitas. 2003; 46: S7-S16.

4 Stanczyk FZ. All progestins are not created equal. Steroids. 2003; 68:879-890.

5 Holtorf K.The bioidentical hormone debate: are bioidentical hormones (estradiol, estriol, and progesterone) safer or more efficacious than commonly used synthetic versions in hormone replacement therapy? Postgraduate Medicine. 2009 Jan;121(1):73-85

Source: Donna White: