Do these heavily promoted hormones justify the claims made for them?
"Bioidentical" hormones have been promoted as safer and more effective than FDA-approved hormones. The exaggerated claims go beyond relief of menopausal symptoms, suggesting they are a veritable fountain of youth.
It's understandable that women would be interested in a different approach now that long-term use of conventional hormone therapy (HT) does not prevent cardiovascular disease as researchers had hoped.
Most clinicians now counsel midlife women differently than they once did. Instead of urging women to weigh the risks and benefits of long-term HT for health, most now suggest HT only for short-term symptom relief. But many women want more from HT, and some look to bioidenticals.
What are bioidentical hormones?
The term "bioidentical" doesn't have a precise medical definition. The Endocrine Society defines bioidentical hormones as "compounds that have exactly the same chemical and molecular structure as hormones that are produced in the human body." Clinicians usually use the word to describe preparations containing either progesterone or one or more of three estrogens — estradiol (the predominant estrogen in premenopausal women), estrone, and estriol (the main estrogen produced during pregnancy).
Evaluating the claims for bioidenticals
Here are some of the claims made about bioidenticals:
Claim: Bioidentical hormones are not drugs because they are molecular copies of the hormones made by women's bodies.
Evidence: The FDA defines drugs as "articles (other than food) that are intended to affect the structure or any function of the body." If bioidentical hormones are designed to relieve menopausal symptoms or have other body changing properties — such as relieve hot flashes or improve the skin — their effects on the body's structure or function are undeniable. Therefore they are drugs.
Claim: Drug companies don't invest in bioidentical hormones because they can't make money from them; you can't patent natural substances.
Evidence: This is at best a half-truth. A drug company can't patent a naturally occurring hormone, but it can patent a process needed to render it absorbable as a drug. Several large drug companies have done just that (or have licensed process patents) and sell FDA-approved bioidenticals.
To bring a drug to market, drug companies invest millions of dollars in research and development, including the randomized clinical trials testing its safety and effectiveness that are required for FDA approval. A drug company must also keep tabs on a drug after it's in use, reporting side effects and monitoring quality.
Claim: Bioidenticals are safer than synthetic hormones.
Evidence: Understandably some women look for a safer alternative for symptom relief. Premarin is synthesized from the urine of pregnant mares and contains a mix of estrogens (some unique to horses), steroids, and various other substances. Might some unidentified molecule be responsible for the health risks? To many, the claim that bioidentical hormones are safer because they have the same chemical structure as those produced by our own bodies would seem plausible.
Yet there's no good evidence to support this claim. Although bioidentical progesterone and the bioidentical estrogen estradiol have been approved, they haven't been studied in large, long-term trials. They're FDA-approved because they've been shown in trials to relieve menopausal symptoms and reduce the risk of osteoporosis. These claims are allowed on their packaging. And similar to other FDA approved estrogens and progestogens, these bioidenticals also carry black box warnings. Hormones from compounding pharmacies, which aren't FDA-approved, don't come with package inserts bearing the black box warning, giving the illusion of being safer than commercially marketed drugs. But the lack of a warning doesn't mean they're safer, only that compounding pharmacies aren't required to detail potential risks. To date, hormones from compounding pharmacies haven't been tested in clinical trials. Until then, the risks associated with them cannot be fully known. Finally, while compounding pharmacies are regulated by state pharmacy boards, they're not required — as manufacturers of approved drugs are — to report on side effects or other adverse outcomes from their products.
There actually may not be much difference between an FDA-approved bioidentical and the custom-compounded version. Both are made from the same hormones and manufactured according to the requirements of the United States Pharmacopeia (a nongovernmental authority that sets standards for prescription and over-the-counter drugs). At a compounding pharmacy, hormones are placed in a capsule, gel, cream, suppository, or other vehicle. A pharmaceutical company follows the same procedure, but it must use a standard dose in a specific vehicle because the two have been tested and approved as a unit. In this respect, an FDA-approved bioidentical may be more reliable.