Exemestane (Aromasin)

Aromasin (Exemestane) is a steroidal suicide aromatase inhibitor, which means that it lowers estrogen production in the body by blocking the aromatase enzyme, the enzyme responsible for estrogen synthesization. The estrogen suppression rate for exemestane is quite effective at ~85% for estradiol (E2) after 10 days of 25mg per day.

Exemestane reaches steady blood plasma levels after a week of administration and this is also when we see it begin its maximal effect on reducing circulating estrogen levels. It’s has a ½ life of 27 hours, so taking it once per day is going to build up blood plasma levels to a very effective level.