You are here

Bewildered by Bio-Identical Hormones


Are bio-identical hormones safe for treatment in menopause? I have no symptoms but did have a blood clot in my calf years ago when I was first pregnant. I was told then to never take estrogen. Could I safely take bio-identical hormones? I'm asking because I recently saw Suzanne Somers on the Oprah show discussing hormone replacement with bio-identical hormones. She says they are making her feel great. CBC's "The National" last week said that drug company hormone therapy, too, is now considered safe.


Thank you for your question about bio-identical hormone therapy. Each "side" wants us to believe that hormones are safe and to ignore the questions we should all ask: What do I want to treat? Has this medicine been shown to be an effective treatment for this problem? Is this hormone safe for me?

I agree that it is confusing when a form of estrogen that is called "bio-identical" or "natural" is reported to be safe, but the kind of estrogen in Premarin® pills has been proven to cause heart disease, blood clots and strokes. I also saw Suzanne Somers eating her meter-long row of supplements and applying a dab here and a dab there, of what she calls "bioidentical hormone replacement therapy."

I believe that bio-identical hormones are the ideal kind of hormones to use for any necessary treatment because we know how they are metabolized in our bodies and therefore can predict their actions. When something is different from what our bodies make, it may have unexpected effects. For example, medroxyprogesterone (a cousin of progesterone) when used with estrogen treatment, causes an increase in breast cancer risk (1). However, the bio-identical, natural progesterone (Prometrium®) with estrogen prevents a 29% estrogen-related breast cancer increase (2).

What most of us don't realize is that many official drugs—made by pharmaceutical companies and licensed by the FDA or Canada's Health Protection Branch—are bio-identical. For estrogen (officially called 17-beta estradiol), the list of drugs that are bio-identical include Estrace®, Estragel®, Estradot®, Estraderm®, and Climera®. For progesterone, there is Prometrium® and, in some places, a vaginal gel.

There is another reason for the debate over bio-identical hormones—they are regulated differently in different countries. In the USA, bio-identical hormones can be obtained without a prescription as a "dietary supplement". In Canada they are considered drugs and must be prescribed by a health care provider. That being said, in both the USA and Canada, most compounding pharmacists are trained and certified by an organization that ensures quality control—purity of the basic hormone preparation, careful measurement of the dose, and excellent reliability of the finished medicine.

This is the other important issue that was ignored in the Suzanne Somers episode—any hormones, bio-identical or not, should be used with care. They are not like skin lotion or aspirin. Bio-identical hormones are powerful substances with effects throughout our bodies. We use hormones for a reason. Would you take an antacid if you didn't have heart burn? A pain pill if you have no discomfort? A sleeping pill if you're sleeping well? I don't think so. Menopause is not an illness. It is normal. Low estrogen and progesterone levels are also normal for menopausal women. Menopause causes no problems for the majority of menopausal women.

However, some menopausal women do need treatment with what I call "Ovarian Hormone Therapy" (OHT, progesterone with transdermal estradiol). OHT is needed and scientifically justified in menopausal women for these two reasons:

  1. Early menopause that occurred before age 40. It is appropriate to continue bio-identical hormones until age 52 (the average age of menopause), then taper and stop estrogen. You can safely continue progesterone if hot flushes persist.
  2. Osteoporosis in a woman who is newly menopausal who also has intense night sweats chronically disturbing sleep. Here the OHT can be safely continued for five years before a bone loss-stopping medicine, such as a bisphosphonate, is added. Then the estrogen can be tapered and stopped. Again, progesterone should be continued until off the estrogen and may be safely continued if needed for hot flushes

Severe hot flushes/night sweats only need progesterone or medroxyprogesterone (which is as effective as estrogen) (3).

Now to answer your question: it sounds like you do not need any hormone therapy. If you did, suddenly, start having hot flushes, you can use progesterone cream (20 mg twice a day) that has been shown to improve them (4) and won't increase clotting. I believe that a woman with a past blood clot should never take a pill form of estrogen, whether bio-identical or not, because that will increase her already increased risk for a second blood clot. You should use caution also, and have a very strong reason for taking estrogen as a patch, gel or vaginal form, although these are less likely than pill estrogen to cause blood clots (5).

Back to Oprah and Suzanne—given that menopause is a normal part of every woman's life cycle, and not a disease—I strongly question the use of any hormone therapy, bio-identical or not, in healthy menopausal women. The notion of menopausal hormone "replacement" is just plain wrong.

I hope this is helpful for you,

All the best,



Reference List

  1. Chlebowski RT, Hendrix SL, Langer RD, Stefanick ML, Gass M, Lane D et al. Influence of estrogen plus progestin on breast cancer and mammography in healthy postmenopausal women: the Women's Health Initiative Randomized Trial. JAMA 2003;289(24):3243-53.
  2. Fournier A, Berrino F, Clavel-Chapelon F. Unequal risks for breast cancer associated with different hormone replacement therapies: results from the E3N cohort study. Breast Cancer Res Treat. 2008;107(1):103-11.
  3. Prior JC, Nielsen JD, Hitchcock CL, Williams LA, Vigna YM, Dean CB. Medroxyprogesterone and conjugated oestrogen are equivalent for hot flushes: a 1-year randomized double-blind trial following premenopausal ovariectomy. Clin.Sci.(Lond) 2007;112(10):517-25.
  4. Leonetti HB, Longo S, Anasti JN. Transdermal progesterone cream for vasomotor symptoms and postmenopausal bone loss. Obstet Gynecol. 1999;94:225-8.
  5. Scarabin PY, Oger E, Plu-Bureau. Differential association of oral and transdermal oestrogen-replacement therapy with venous thromboembolism risk. Lancet 2003;362(9382):428-32.
Life Phase: 
Perimenopause, Menopause
Updated Date: 
Tuesday, November 19, 2013 - 13:15

Estrogen’s Storm Season: Stories of Perimenopause

Estrogen's Storm Season

by Dr. Jerilynn C Prior

New second edition available


All royalties support CeMCOR research.


Purchase your ebook copy via our Amazon Kindle or
Google Play storefronts!

Paperback copies (with updated insert) still available here.

Join a Study:

Get Involved
