Anadrol is quite a special steroid in that sense, since in spite of being a DHT derivative, which can not aromatise into estrogen, it still causes estrogen related side effects. It is still not 100% clear to the scientific community to as how anadrol is capable of causing estrogen related side effects, but there seems to be a general consensus that it can directly activate the estrogen receptors without going through modifications. Therefore, it is useless to use AI's on anadrol cycles, since the aromatase enzymes are not involved in the estrogen related side effects. Therefore, only one option is left here - to reduce the estrogen receptors that are activated by anadrol, and the best compound for this are the selectice estrogen receptor modulators (SERM), such as nolvadex, which should be taken at a dosage of 50 mgs per day.