Is bio-identical progesterone safe?
Bio-identical progesterone is claimed to be safer than its synthetic counterparts, which are collectively called progestins. The most commonly used progestin is medroxyprogesterone. In the Women’s Health Initiative Trial, the study arm that took Prempo® (a combination of medroxyprogesterone and conjugated equine estrogen) had a higher risk of breast cancer compared to placebo. Scientists surmise that, while estrogen stimulates the growth of breast cancer, progestin increases the blood supply to tumors, facilitating growth. Bio-identical progesterone has the same effect on breast tissue, so there is no reason to assume it is safer than progestins with regard to breast cancer. After menopause woman make estrogen in fat tissue. If you have a significant amount of estrogen, even though you are post-menopausal, and you use OTC progesterone, you may be increasing your risk of breast cancer. Topical progesterone products are available over the counter. This author advises that they not be pre
