The efficacy of Isa-Test’s incredible testosterone-enhancing and estrogen-reducing effects were scientifically documented by researchers Rob Mendel, PhD, and Dr. Tim Ziegenfuss of the Ohio Research Group of Exercise Science and Sports Nutrition! The conclusion of the study was after just three weeks (and Isa-Test works on a progressive basis), Free or usable Testosterone levels increased by up to 154%, and estrogen levels decreased by up to 43%. Equally important, all of the subjects' health markers (e.g., liver, kidney, cholesterol, blood pressure, etc.) were normal and healthy. So, we know, without a reason of a doubt, Isa-Test works impressively fast and is completely safe.