Synthetic hormones produce toxic metabolites in the body, whereas natural bioidentical hormones do not. Studies have shown that altered, unnatural hormones will cause side effects. Premarin, derived from pregnant mare’s urine, has over 30 different equine estrogens that are foreign to a female, human body.
Provera, another synthetic drug, has been molecularly altered and has been known to cause uncomfortable side effects from its very inception. The Journal of the American Medical Association found that progestin (the same content found in Prempro), the synthetic progesterone, raised the risk of breast cancer well beyond the risk found in the use of estrogen alone. This has not been the case with Natural Progesterone. This result was made clear in the Women’s Health Initiative Study which reported that synthetic prempro increased the risk of heart disease, stroke and breast cancer in women.
A study in the Journal of Clinical Endocrinology and Metabolism reported that out of the women who were placed on three different regimens: estrogen, estrogen and progestin, or placebo, the women on estrogen and progestin had a greater breast epithelial cell proliferation and density than women on estrogen alone or nothing at all. The Journal of the National Cancer Institute has also concluded that there is an associated 10 percent higher risk of breast cancer for every five years of supplementation with a synthetic progestin. The common denominator, of course, is the synthetic progestin.