Its important to remember the difference between the classification of an AI and a SERM. Like most others I use and advocate the use of an AI while running aromatisable compounds. In theory it should go a long way to preventing gyno from forming. However, sometimes even with an AI gyno will occur; more commonly it occurs because of a lack AI use. The bottom line is occur the gyno forms and you have that gland like TNH can attest to its always going to be there. You can come off all AAS or mega dose on the AI's like letro and it will shrink; but it is still there. What Nolva and Torem are particularly effect at is treating the gyno and breast issue. Remember that most AI's and SERM's were created to target breast cancer. In different ways they all work thru different path ways. The AI's unquestionably lower estrogen in the body to a greater degree than SERM's. However, once again, some of the SERM's when it specifically comes to dealing with the activated tissue and gland are more effective at that specific task.