1,4,6-Androstatrien-3,17-dione (ADT)
From what I understand, and please correct me if I'm wrong, ATD is a type of AI. ATD is a type of AI that is known as a Suicide Inhibitor. Most that I know of don't like using ATD's due to the fact that it kills the aromitase enzyme. Another and more popular AI you should read up on is a Competitive Inhibitor. In a Comp Inhibitor the molecule just fills the active binding site of the aromatase enzyme and won't let it act on your free test. This means the body still sees the aromatase enzyme floating around and doesn't register to make more enzymes. On the other hand, with something like ATD a suicide inhibitor, the body sees the lack of enzymes (due to ATD killing them) and makes more aromatase enzymes for use. Both will work for PCT, but again most will recommend a competitive AI. Do some reseach on Advanced PCT by Anabolic Xtreme. It contains 6-Bromo which is a Comp AI. Good luck.