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The Bio-Identical Hormone Debate: Must Reading for Anyone Considering Bio-Identical Hormone Replacement Therapy

My patients frequently ask me why I keep saying that Bio-Identical hormones (especially estrogen and progesterone) are so much safer and more beneficial than synthetic hormones (conjugated equine estrogens and progestins).

An excellent literature review was conducted by Kent Holtorf and titled "The Bio-Identical Hormone Debate: Are Bio-Identical Hormones (Estradiol, Estriol, and Progesterone) Safer or More Efficacious Than Commonly Used Synthetic Versions in Hormone Replacement Therapy". The full text can be downloaded here.

It describes and summarizes 196 studies that investigated Bio-Identical versus synthetic hormones, specifically with a focus on breast cancer and cardiovascular disease. They chose these 2 diseases because of their primary importance and the confusion and controversy surrounding them and synthetic versus Bio-Identical hormones. (If they had also reviewed the literature regarding the many additional significant benefits of Bio-Identical hormones with respect to diseases such as Alzheimer's disease, colon cancer, osteoporosis, macular degeneration, etc., they would have had to review thousands of studies more).

The evidence is substantial and compelling.

Some of the conclusions:

1. Synthetic progestins (such as medroxy-progesterone or levonorgestrel) significantly increase the risk of breast cancer, while Bio-Identical progesterone decreases the risk of breast cancer.
2. Synthetic estrogens (such as conjugated equine estrogens) significantly increase the risk of breast cancer, while Bio-Identical estriol does not.
3. All estrogens have a very positive effect on lipids and reduce coronary artery spasm, which protects the heart, and may reduce heart disease by 50% when combined with Bio-Identical progesterone. Substituting a synthetic progestin, not only negates this protective effect but also increases risk of heart disease significantly.
4. Synthetic estrogens significantly increase the risks of blood clots, whereas transdermal Bio-Identical estrogen does not.
5. Synthetic progestins also significantly increase the risk of blood clots, whereas Bio-Identical progesterone reduces this risk.

If your doctor or anyone else tells you that there is insufficient evidence to support the use of Bio-Identical Hormone Replacement Therapy, just download this article and hand it to him or her.

I also encourage you to download this article and read it yourself if you have any concerns or doubts.

Dr. Mark Rosenbloom, M.D.