At Ageless Solutions, we offer bioidentical hormone treatments for men and
women. We found this article from Harvard Women’s Health Watch to be
most helpful in describing bioidentical hormones. To learn more, call us
What are bioidentical hormones?
(This article was first printed in the August 2006 issue of the Harvard Women’s
Health Watch. For more information or to order, please go to
Many women and health experts continue to struggle with the turnaround in
attitude toward hormone therapy in the wake of the Women’s Health Initiative
(WHI) trial of combined estrogen and progestin (as Prempro) for preventing later-
life ills. The trial was stopped early, in 2002, because hormone users had a higher
risk of breast cancer, heart disease, stroke, and blood clots. Though the added
risks were small, many women and their clinicians concluded they must
discontinue hormone therapy. Many of these women found that hot flashes,
sleeplessness, and other menopausal symptoms returned with a vengeance.
Hormone therapy is still considered the most effective treatment for symptoms.
But women are not rushing back. One concern of health experts is that women are
turning to alternatives they think are safer — but may not be.
Even before the WHI results came in, many women were looking for something
different to relieve hot flashes, night sweats, and vaginal dryness. Some women
disliked the side effects of hormone therapy, such as breast tenderness or
bleeding. Others worried about estrogen’s link with breast cancer. Still others
were opposed to taking drugs for symptoms because doing so implies that
menopause is a disease rather than a normal life passage. Some women objected
to the use of pregnant mares’ urine — the source of estrogen in oral conjugated
equine estrogens (Premarin), the only estrogen tested in the WHI trial.
In search of “natural”
Many women assume that “natural” hormones would be better or safer — but the
term “natural” is open to interpretation.
Any product whose principal ingredient has an animal, plant, or mineral source is
technically natural. It doesn’t matter whether the substance is ground, put into
capsules, and sold over the counter — or extracted in a laboratory, manufactured
by a pharmaceutical company, and made available only by prescription. For
example, the soy plant is the source of supplements that some women take to ease
menopausal symptoms; it’s also used, along with yams, to make the estrogen in
the FDA-approved hormone drug Estrace.
But unlike Estrace, soy supplements aren’t regulated and haven’t been rigorously
tested in humans, so we don’t know whether they’re safe or effective. There’s
some evidence that certain soy components may actually stimulate breast tumor
growth. So “natural” doesn’t necessarily equal “safe” — and may simply be a
euphemism for “unregulated.”
The interest in a more natural approach to hormone therapy has focused attention
on bioidentical hormones — hormones that are identical in molecular structure to
the hormones women make in their bodies. They’re not found in this form in
nature but are made, or synthesized, from a plant chemical extracted from yams
and soy. Bioidentical estrogens are 17 beta-estradiol, estrone, and estriol.
(Estradiol is the form of estrogen that decreases at menopause.) Bioidentical
progesterone is simply progesterone. It’s micronized (finely ground) in the
laboratory for better absorption in the body.
Bioidentical hormone therapy is often called “natural hormone therapy” because
bioidentical hormones act in the body just like the hormones we produce. But here
again, that tricky word natural muddies the waters. Pregnant mares’ urine is
natural, but Premarin is not bioidentical, at least not to human estrogen. The same
goes for Cenestin, which is made from plants but is not bioidentical.
Technically, the body can’t distinguish bioidentical hormones from the ones your
ovaries produce. On a blood test, your total estradiol reflects the bioidentical
estradiol you’ve taken as well as the estradiol your body makes. On the other
hand, Premarin is metabolized into various forms of estrogen that aren’t measured
by standard laboratory tests. Proponents of bioidentical hormones say that one
advantage of bioidentical estrogen over Premarin is that estrogen levels can be
monitored more precisely and treatment individualized accordingly. Skeptics
counter that it hardly matters, because no one knows exactly what hormone levels
to aim for, and symptoms, not levels, should be treated and monitored.
How do I find bioidentical hormones?
Bioidentical estrogens and micronized progesterone are made into a range of
products, many of which are FDA-approved and available with a prescription at
your local drugstore (see chart, “FDA-approved hormones for menopausal
symptoms”). Commercially available bioidentical estradiol comes in several
forms, including pill, patch, cream, and various vaginal preparations. Micronized
progesterone comes in a capsule or as a vaginal gel.