If you watch Oprah or read books by actress Suzanne Somers, you've probably heard about "bioidentical" or "natural" compounded hormones. This phrase is being used primarily to discuss the hormones estrogen and progesterone and medication that is "compounded" or mixed in pharmacies that provide individualized medical therapies.
Somers and others claim that bioidentical hormones are identical to the hormones your own body produces and are more effective at controlling menopausal symptoms and age-related changes. They also claim that bioidentical hormones are safer than hormone therapy approved by the U.S. Food and Drug Administration. However, there is no evidence to support these claims, according to the North American Menopause Society (NAMS) and other medical organization.
The push for bioidentical compounded hormones came after the results of the Women's Health Initiative (WHI) were released in 2002 and 2003. The large, government-sponsored study showed a slightly increased risk of breast cancer and cardiovascular disease in women who took a synthetic form of estrogen/progestin therapy called Prempro and a slightly higher risk of stroke in women who took the estrogen-only therapy, Premarin.
Yet both NAMS and The Endocrine Society warn women about bioidentical hormones, noting that there is no medical or scientific evidence supporting the claim that the results in the WHI had anything to do with the type of hormone therapy used. They also note that there is no evidence that the results would have been different if other types of hormone therapy were used, including bioidentical hormones.
Plus, the reality is that the estrogen used to make bioidentical hormones—estriol—is the same estrogen found in numerous FDA-approved hormonal therapies: the oral medications Estrace and Gynodiol; patches and creams (Climara, Alora, Estraderm, Vivelle); vaginal cream (Estrace); and a vaginal ring (Femring).
The other concern about the bioidentical hormones championed by Somers and others is that they are created in compounding pharmacies. These are special pharmacies that use already approved drugs or natural ingredients to create unique formulations—such as a liquid from a pill for someone who can't swallow pills. These medications do not have FDA approval because they haven't been tested to prove that you can absorb the hormones appropriately to reach the levels in your blood and other tissue required to provide benefits. Plus, there is no scientific evidence about the effects of these medications on the body—either good or bad.
In addition, the FDA does not regulate these pharmacies even though the stores are, in effect, manufacturing tiny amounts of drugs. In January 2008, the FDA sent warning letters to seven compounding pharmacies to stop making unsubstantiated claims about the safety and benefits of compounded estrogens and progesterone, saying there is no evidence that the drugs "are superior to FDA-approved menopausal hormone therapy drugs or that they prevent or treat serious diseases, including Alzheimer's disease, stroke, and various forms of cancer."
Some bioidentical hormones were made with estriol, a weak form of estrogen primarily produced during pregnancy. Since there are no FDA-approved products made with estriol, in 2008 the FDA banned pharmacies from using it, noting that "no drug containing estriol has been approved by FDA and the safety and effectiveness of estriol is unknown."
Among the many claims for estriol was it had a much lower risk of breast cancer than other types of supplemental estrogen. This is based on a theory espoused in the 1970s but never proven. In fact, high levels of any of the three types of estrogen a woman produces herself—estradiol, estrone (the least prevalent of the three types) and estriol—can stimulate the growth of breast cells and increase the risk of breast cancer.
As for claims that bioidentical hormones are more "natural" than those mass produced, the estrogen used in the most commonly used hormone therapies—Prempro (conjugated estrogen and medroxyprogesterone) and Premarin (conjugated estrogen)—are made from a natural ingredient: pregnant mares' urine.
Compounded progesterone uses plant-based progesterone (which is not bioidentical) to create progesterone cream. However, the primary reason for prescribing progesterone with estrogen therapy is to prevent the estrogen from stimulating the uterine lining, which can cause uterine cancer. There is no evidence, however, that topical progesterone has this effect.
There is also no evidence that bioidentical progesterone increases metabolism, helps you lose weight, reduces the risk of heart disease or counteracts the effects of stress hormones, as some proponents claim. However, there is some evidence that women experience greater relief from peri- and post-menopausal symptoms when they take hormone therapy with progesterone rather than products made with synthetic progestins.