Arimidex (Anastrozole) is a selective, nonsteroidal aromatase inhibitor so it a competitive aromatase inhibitor. The key to this med is how it achieves the aromatase inhibition. Arimidex is a REVERSIBLE antagonist that binds to the aromatase enzyme. In simple terms arimidex will bind to aromatse preventing the conversion of testosterone to estrogen but after X amount of time it will unbind and testosterone will be able to be converted to estrogen. So while you are taking the med you will have lower estrogen levels but you need to keep taking it. Anastrozole does causes an 85% decrease in estrone sulfate levels. Just because you have lower estrogen levels do not mean that you can not get gynecomastia it will just reduce the chances.
Here are some key points:
-Onset of estradiol reduction: 70% reduction after 24 hours; 80% after 2 weeks therapy
-Duration of estradiol reduction: 6 days
-Absorption: Well absorbed; extent of absorption not affected by food
-Half-life elimination: ~50 hours
-Time to peak, plasma: ~2 hours without food; 5 hours with food
Aromasin (Exemestane) is an IRREVERSIBLE steroidal aromatase inactivator. That is it irreversibly blocks the active site of the aromatase enzyme for the life of the enzyme, leading to inactivation (***8220;suicide inhibition***8221 and thus preventing conversion of androgens to estrogens in peripheral tissues. Remember that your body will produce more aromatase enzymes.
Some more key points
-Absorption: Rapid and moderate (~42%) following oral administration; absorption increases ~40% following high-fat meal
-Half-life elimination: 24 hours
-Time to peak: Women with breast cancer: 1.2 hours
Both meds have good benefits but I would lean towards Arimidex for estrogen control because you dont want your estrogen to low and I am sure many people on here are not getting there estrogen levels checked. I have to stress that neither one of these meds will prevent gynecomastia. They will how ever help reduce the chances of it developing. If you are on either one of these or are sensitive to estrogen and start to devlop signs of gynecomastia then you might want to get some Nolvadex. Nolvadex is the only one that has properties which compete with estrogen for binding sites in breast.
