I would be a bit careful when you start messing with your free test levels. Depending on how much of an alteration your doing, and depending on the individual, you might be putting your body at some risk. Is D-Test an Anti-Aromatase? If it is, taper yourself off. Don't stop cold turkey. It could spike your estro levels. If it isn't you might run the risk of gynecomastia and have to buy a bra. I used to run supplements for a bit. I don't touch the stuff anymore. Just clean diet, some protein, and tons of water will do you well! However, If you really want some incredible gains with minimal side effects, Prime by USP labs was pretty darn good. But in all honesty, your probably better off in the long run not touching the stuff.