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  • With Mayo Clinic gynecologist and obstetrician

    Mary Gallenberg, M.D.

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Mayo Clinic Health Manager

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Question

Bioidentical hormones: Are they safer?

Are bioidentical hormones safer and more effective than traditional hormone therapy? They sound like they would be because they're customized to the individual.

Answer

from Mary Gallenberg, M.D.

There's a lot of interest in bioidentical — or so-called "natural" — hormone therapy for menopause symptoms. However, there's no evidence that bioidentical hormones are safer or more effective than standard hormone replacement therapy.

Bioidentical hormones are custom-mixed formulas containing various hormones that are chemically identical to those naturally made by your body. These prescription and over-the-counter products are marketed as being tailored to a woman's individual hormone needs, typically determined through saliva hormone testing. Manufacturers claim that bioidentical hormones are safer than standard, FDA-approved hormone therapy.

According to the North American Menopause Society (NAMS), custom compounds may provide certain benefits, such as individualized doses and mixtures of products and forms that aren't available commercially. However, they may also pose risks to consumers. These compounds haven't been approved by the Food and Drug Administration (FDA) and as a result haven't been tested for purity, potency, efficacy or safety. These products may even contain unknown contaminants. For this reason, NAMS does not recommend these custom-mixed products over well-tested, government-approved commercial products for the majority of women.

Also, bioidentical estrogen and progesterone are available in FDA-approved hormone therapy products, including:

  • Estradiol, such as Estrace, Climara patch and Vivelle-Dot patch
  • Natural progesterone (Prometrium)

These products come in many different doses and forms. So, you don't need to turn to unregulated, individually compounded products as your only source of "natural" hormones.

Next question
Hormone replacement therapy: Can it cause vaginal bleeding?
References
  1. Endocrine Society, Bioidentical Hormones, October 2006, accessed July 17, 2007, www.menopause.org/bioidenticalHT_Endosoc.pdf
  2. The North American Menopause Society, Understanding the controversy: Hormone Testing and Bioidentical Hormones, updated March 15, 2007, accessed July 19, 2007, www.menopause.org/edumaterials/PG06monogrpah.pdf
  3. Martin K. Preparations for postmenopausal hormone therapy.  http://www.uptodate.com/home/index.html. Accessed  August 18, 2009.

AN01133

Aug. 25, 2009

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