I'm currently working on losing a lot of fat. Lost about 28 pounds (definately have gained muscle and strength) and am currently using an e/c stack. I still feel I have about 20 or so more pounds to lose. (for some reason, my goal gets to a lower and lower weight lol., It's been "25 lbs" since I started. Even though I've lost 28, I still have 20 to go....) Anyway, heard GREAT things about YES, but was wondering if I should wait to use it. Like when I get my bf around 16-17%.