Bioidentical hormones or so-called “natural hormones” are plant-derived hormones which are identical in structure to endogenous hormones produced by the body. Because bioidentical hormones have low absorption with oral administration, they are frequently formulated as a gel to be applied topically to the skin. They include estradiol, estriol, estrone, and progesterone. They are usually formulated by compounding pharmacies. Bioidentical hormone replacement therapy (BHRPT) is typically used to relieve symptoms of menopause, but is also prescribed for its alleged anti-aging effects. Bioidentical hormones have been promoted usually, by people outside the conventional medical community, as a safer alternative to traditional hormone replacement therapy. The US Food and Drug Administration, however, has warned multiple compounding pharmacies that the claims they make about the efficacy of bioidentical hormones are misleading and are not supported by medical evidence. (The FDA letter can be read here.)
The Endocrine Society’s October 2006 Position Statement says, “…many ‘bioidentical hormone’ formulations are not subject to FDA oversight and can be inconsistent in dose and purity. As a result of unfounded but highly publicized claims, patients have received incomplete or incorrect information regarding the relative safety and efficacy of hormone preparations that are referred to as ‘bioidentical.’” The American Association of Clinical Endocrinologists shares a similar perspective, “…AACE believes that potentially serious dangers of BH [Bioidentical Hormones] use have not been sufficiently exposed. The primary concern about bioidentical hormone use is patient safety. These substances have not been shown within the medical community to be clinically effective. In addition, utilization of these formulations may be associated with various risks inherent in the compounding process.”
Essentially, the assertions made by the scientific community about BHRT condense into four criticisms: there is no medical evidence to support the claims about the increased effectiveness and safety of BH; the majority of compounded products have not undergone rigorous testing; there are significant concerns about the purity, potency and quality of BH; and “hormone therapy does not belong to a class of drugs with an indication for individualized dosing.” (Stephen Barret of Pharmwatch.com). Unfortunately, clinical testing of bioidentical hormones may never be done because the pharmaceutical industry has no economic interest in their promotion. Since recent studies using traditional oral hormone replacement therapy have shown negative consequences with long term use, it is reasonable to further study bioidentical hormones in menopausal women to possibly make them more generally available as prescription drugs.