I know it is a theory that has been tossed around, and really never been proven or disproven. I recently finished up a cycle of TNE and Tren, in which i hit my bis 5 x a week. Rotating on the corners and in the middle, pretty much wherever i couldnt see a vein. I have been off for almost a month, and although i grew everywhere, I put 5/8 of an inch on my arms, and My bis are extremely vascualr now, even while off. In week 12, I had right around an inch difference from when i started, due to inflamation, but, when it was all said and done, 5/8 an inch is fairly signifigant. I never have had put that much growth on them before. I think it was a little because of the tren, but more because of the TNE. I dont think longer esters willl produce any growth, besides local irritation. Or maybe, I grew because of strecthing the muscle fascia so much, and not because of the unesterfied gear.