03/28/2010 05:12 am ET Updated May 25, 2011

Bioidentical Hormones: A Lot of Fancy and Very Little Fact

When Hollywood celebrities tout a product or fad, a number of our fellow Angelenos tend to jump on the bandwagon. Such has been the case with bioidentical hormones to treat menopausal symptoms. Indeed, one of the major proponents of these therapies is Suzanne Somers, who has authored several books detailing her experiences with them. Somers promotes bioidentical hormones to middle-aged women claiming that they can feel young and sexy again, and that these therapies are superior and safer than the pharmaceutical company manufactured, FDA-approved hormones. Unfortunately, I am not aware of any credible scientific evidence that these claims are true.

The term "bioidentical" means that the material has the same chemical and molecular structure as a substance produced in the human body. Unlike hormones made by pharmaceutical companies (some of which are indeed identical to those made by the human body), some of the bioidentical hormones that are promoted on late night infomercials are made in compounding pharmacies and formulated as creams, gels, drops or capsules. Compounding pharmacies can take an FDA-approved substance and alter the dosage without FDA oversight.

Menopause occurs when the ovaries cease to produce eggs and no longer make the hormones estrogen and progesterone. The estrogen deficiency results in loss of periods, dryness of the vagina, hot flashes and drenching sweats. In turn, many women suffer from insomnia and daytime tiredness, mood swings and pain during intercourse. These symptoms usually respond to estrogen treatment and, based on the studies that I've seen, it doesn't make any difference whether the estrogen is derived from a plant, an animal's urine or synthesized in a test tube. At equivalent potencies, all estrogens should relieve the symptoms equally.

Why do so many women follow the advice of the celebrity proponents of bioidentical hormones? I assume there may be a number of reasons. Some people have a distrust of mainstream medicine and have not been satisfied with the results. Others believe that the use of a "natural" substance that is identical to one that was produced by the woman's own ovaries sounds like a better idea than taking a synthetic hormone that only resembles the ones produced by the ovaries.

Additionally, a large study of the use of estrogens with or without a progesterone-like drug, the Women's Health Initiative sponsored by the National Institutes of Health, showed that women who had gone through menopause many years before and were then started on an estrogen and progestational drug combination pill had an increased risk of heart disease and breast cancer. The resulting publicity surrounding this study caused many women stop their hormone therapy. Some turned to bioidentical hormones assuming they were a potentially safer alternative.

So, what is wrong with bioidentical hormones? First is the premise. There does not appear to be any scientific evidence that bioidentical hormones are safer or more effective than the FDA-approved drugs. A bioidentical hormone that has the same potency as a pharmaceutical manufacturer's hormone would, in all likelihood, have the same risks and benefits of the pharmaceutical hormone. More importantly, however, is the concern that the compounding pharmacies that produce the bioidentical formulations often make products that contain less than or more than the ordered amount of drug, and the materials that they add to the active drug may alter the absorption of the drug. Indeed, I have measured hormone levels on many women using bioidentical hormones only to find some had toxic levels of the hormone while others had markedly subtherapeutic levels.

The concept of personalized medicine is a wonderful idea - we are all genetically different and we all react to medications a little bit differently. Therefore, if we could figure out your specific requirements, we could design a therapy that would be just right for you. The promise of this is starting to be realized in a few areas, but not when it comes to hormone therapy for menopause. There are no measurements that can be made on saliva, blood or urine that will tell a physician or pharmacist exactly what combination of hormones would be ideal for a particular woman.

The term "bioidentical hormone" is a marketing term, not a medical or scientific term. Because of the inconsistency from batch to batch or compounding pharmacy to compounding pharmacy, the uncertain absorption of the active drug, and the fact that the risks of adequate amounts of bioidentical drugs are the same as those produced by the FDA-monitored pharmaceutical products, whose absorption and pharmacokinetic (the process by which a drug is absorbed, distributed, metabolized and eliminated by the body) characteristics are known, I recommend that women use the FDA-approved pharmaceutical products under the direction of their physician.

While bioidentical hormones are a popular celebrity trend, whatever you do, I strongly encourage you not to rely solely on obtaining your medical advice from Hollywood.