Everybody reacts differently to slin. I have historically put on fat VERY easily and have had a hard time adding muscle naturally. Using slin preworkout with AAS puts muscle on me and leans me out at the same time since I only eat carbs pre, during and post workout.
It works wonders by allowing me to eat a lot more calories/carbs than normal (all around the workout) and not get fat. The glycogen goes to where its supposed to go...the muscle.
I've eaten as high as 500 g of carbs around my workout and not gotten fat. Right now I'm closer to 350 g.