when you are in pct, you are going to get a major spike in cortisol... cortisol is termed the "gains killer" for a reason... it will put you into a catabolic state which will not allow you to build muscle and at the same time will eat it away, on top of the fact you will also get unwanted fat gain... so you will lose muscle and gain fat that you had just busted your ass an entire cycle for... GW prevents the rise in cortisol... not only that but it keeps you performing at a level you were while on cycle being the ultimate performance enhancers it is...