Bioidentical hormones have the same molecular structure as hormones produced by the human body. Both pharmaceutical companies and compounding pharmacies (pharmacies that mix hormones for individual patients) make bioidentical hormones, but compounding pharmacies can vary amounts and ratios of hormones for each individual based on the physician’s prescription (Vogel, 2006). Opponents voice concern about the quality, purity, and potency of the ingredients of bioidentical hormones from compounding pharmacies due to less stringent FDA oversight (Benda, 2008).
Women in other countries, particularly European countries and China, have used bioidentical hormones for many years (Moskowitz, 2006). Unfortunately, few studies have examined the health consequences for women using bioidentical compared to synthetic hormones (Baber, 2011). However, there are indications that bioidentical estrogen and micronized progesterone may be safer in regard to breast cancer and heart disease compared to synthetic hormones (Oz & Roizen, 2010). A 12-year French study of almost 100,000 women found that those who used estrogen and a bioidentical progesterone that is unavailable in the United States experienced no significant increase in breast cancer compared to women who never took any menopausal hormones (Fugh- Berman, 2008).