Is there any evidence proving that you need estrogen to build muscle. Im wondering b/c im on a cycle now, growing and using 12.5mg aromasin ED and estro for me is supposed to be between 0-52 or <52 Mine came back at 46 Now i'd presume this would be good for building muscle right? do you want it in range but in the higher end? Or lets say I used more aromasin and got it down to the 20's or so. Would that make a diff? Im mainly wondering how necassary estrogen is in building muscle.