Like Grayhorse, I know that without exercise I will go back to 180lbs. However, naturally I've been well into the 2's. I'm 6'1 and have great flexability except my arm reaching behind my back.. @218lbs I could still run a 17:28 3 mile. So it really depends on how hard you push yourself. Judging by your pic, it wouldn't take a lot to put on lean muscle.
Besides, if your looking for 20lbs, deca/win may not be the best thing for you. I'd suggest eating a lot and very clean along side getting your ass kicked in the gym. test therapy should only be used as a last resort. Not saying you don't know anything, but getting into test is a whole new ball game of knowledge, with long term effects.
Testing... If it was for work, Testing would have to be specific. If it was for a sport, that would be a different story..
Often times I hear "I can't put on muscle or weight", my question to them is "are you human?" Suck it the fuck up, train hard and shovel calories into your mouth, your body wont have an option.
Right now I sit at 205 natural, and I no longer have a left arm. Stop listening to your friend and bust your ass... it's really the only pay off
Me 2 weeks ago...