I used s4 2x
1st, short 1 bottle 4 week cycle
2nd, longer 2 bottle 8 week cycle..
So good results from both times dryer harder stronger but not by much, but it's also cheap so can't complain.
I've seen better results through a strict carb depleted diet and low intensity cardio, but I also used it during recomp, I lost my job so I was a fat fuck and needed quick results since I had gotten fat.. overall I say it's worth a try..