Women have several choices for estrogen replacement therapy today. They can go the synthetic or natural route and can choose an oral or transdermal (patch/cream) preparation.
The liver can use estrogens for the production of hepatic enzymes. This means the liver can metabolize estrogens into other substances, in this case enzymes the liver produces. Oral estrogens are effective, but to some degree their effectiveness is diminished by passing through the liver before being available in the blood stream. On the other hand, transdermal estrogens enter the bloodstream directly, bypassing the liver. Transdermal estrogens are probably more effective in achieving their effects then oral estrogens.
Natural estrogen replacement therapies often combine different forms of estrogen. This means that depending on what conditions are being treated and what your own levels of these are, you can have a formula compounded just for your needs. These formulas are called Triest (containing 3 estrogens) and Biest (contain 2 estrogens). These preparations mimic the 3 natural estrogens in your body, estriol, estrone, and estradiol. Most synthetic oral estrogens are made from horse’s urine and horse’s estrogens, which are not the same as those naturally occurring in your body.
Supplemental estrogens are typically used on all days of a woman’s cycle except during menstruation. They can be used continuously during and after menopause, but most natural doctors recommend a break of 1 week per month if tolerated.
Transdermal delivery of estrogen therapy available by prescription “seems not to alter” the risk of venous thromboembolism (VTE), or blood clotting, in postmenopausal patients when compared to oral delivery, a new study suggests. The study was conducted by researchers at NYU Langone Medical Center and was published in the latest issue of Menopause: The Journal of the North American Menopause Society, March 2009.
Please keep in mind that there are three forms of estrogen – estradiol, estrone and estriol. Estradiol is the most potent, but also associated with increasing breast cancer risk. Estriol, a weaker form, may have protective effects against estrogen sensitive breast cancer. So when recommending or avoiding ‘estrogens’, it is necessary to specifiy which estrogen is being referred to.