Bioidentical is important but transdermal is even more so!
The majority of women take their HRT in pill form by mouth (oral HRT). While very convenient, this results in changes in the metabolism of estrogen that can be harmful. The reason for this is called the "first pass effect." When any substance is ingested, it is absorbed by the intestines and then the whole dose hits the liver immediately. This does not mimic what occurs naturally when the ovaries are releasing estrogen into the circulation gradually all day and then it gradually goes through the liver. When a large amount of estrogen hits the liver at once, the processing of the estrogen changes the metabolism of the liver and results in a number of deleterious effects:
- Increase in clotting factors, hence the warnings on the box that women who smoke and older women may have an increase in blood clots in the veins of the legs that can then cause a potentially fatal pulmonary embolism.
- Increase in the carrier molecule of the sex hormones called 'sex hormone binding globulin,' which can result in too-tight binding of testosterone and thus symptoms of a low testosterone level--decreased libido, vaginal dryness, and thinner bones. Dr. Rogerio Lobo, a nationally known researcher in estrogen replacement therapy has said, "The fastest way to make a woman androgen deficient is to put her on oral estrogen replacement therapy."
- The metabolism of fats and protein is changed which results in the loss of lean muscle and increase in fat. These often counter balance each other to cause no change in weight, but an undesirable body composition.
- When a woman drinks the equivalent of even just one glass of wine or other alcohol a day and takes estrogen orally, her level of estrogen can increase 300% above when she is not drinking. This can cause levels of estrogen that are higher than are ever experienced in a normal menstrual cycle. This may be one of the causes of an increased risk of breast cancer with oral HRT. In contrast, transdermal estrogen results in only a 30% increase in estrogen level with alcohol consumption.
- An increase in the incidence of gall stones which can lead to the need for gall bladder removal.
- An increase in triglycerides, a form of cholesterol that is a known risk factor for heart disease.
- An increase in C-reactive protein, a potent risk factor for CAD (coronary artery disease).
None of these "side effects" occur with transdermal (through the skin) ERT because the daily dose is released gradually into the general circulation, just as when the ovaries are functioning naturally.
So why aren't all women taking their ERT transdermally?
Some of the reasons why more women are not taking transdermal ERT are:
- Inertia: Transdermal therapy has not been available nearly as long as oral therapy, and once a pill-a-day therapy takes hold, it is hard to change the preferences of both physicians and women. Furthermore, most physicians are not trained in prescribing precision amounts of multiple hormones and optimizing them through lab test analysis and dosage modification. Physicians are most often educated about treatment options by pharmaceutical companies, who have nothing to gain by developing and marketing a product that is not patentable.
- Convenience / Availability: Most women don't want to wear a patch. This problem is solved with transdermal creams that exhibit excellent absorption and provide steady estrogen levels. However, the pharmaceutical companies have not yet developed a transdermal cream that combines estrogen with other hormones such as progesterone and testosterone. Women using multiple transdermal hormones must resort to a specialized class of pharmacies that perform compounding, the art of combining several ingredients in customized amounts.
- Oral ERT raises HDL (the good cholesterol) higher than transdermal ERT. This argument is often the sole reason put forth by gynecologists and internists when asked why they persist in prescribing oral ERT in the face of the six reasons against it listed above. The reasoning here is flawed in most cases. While it is true that HDL is raised considerably more with oral therapy, the majority of women have an HDL in a very good range even off ERT so raising them from 60 to 80 mg/dl does not confer enough benefit to outweigh the above negatives. Moreover, it has been shown that only about 30 to 40 percent of the heart disease reduction benefit of ERT comes from the changes in the cholesterol profile, which further mitigates the marginal benefit of raising HDL in a woman with a good baseline level. This is not to say that in some cases, e.g., when a woman's HDL is less than 30, oral therapy on balance is preferable, but certainly not in the majority of cases.
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