I have been wondering this same question for quite some time now. I have tried both ATD and XT numerous times. I am now done with my third m-drol cycle and am using clomidex (ATD) for post cycle. During my previous 2 cycles of m-drol, and my other cycles for that matter, XT or any generic that I used did a great job of preventing and reducing gyno. However, this run I am seeing small lumps form under each nipple; which is driving me EFFING CRAZY. I whole heartedly believe that the clomidex is aggravating my gyno. There is no other explanation. No aspect of this cycle is different from the other cycles that I have ran, and I have ran at least 10 cycles over the years. I am frustrated and angry that this product has been marketed as a post cycle, estrogen elimination, gyno prevention product. I believe this claims are false. Now, I have to scramble around and find legit tamox to order in hopes to kill the gyno that is now forming. I consider myself smart than the average bear when it comes to gyno prevention, and post cycle administration for that matter because I have had blood work, and liver values checked after each cycle and I am still in normal levels because I am not a total retard and adequately do my homework. Is anyone else having this issue? If all ATD does is raise my test levels and aggravate existing gyno then why is it being marketed it a PCT? I'd love to know this answer.