50mgs/ml, that sucks, thats why i love Ttokkyo eq, 200mgs/ml. youll need to inject 8ml of that shit a week to get 400mgs. i would probly inject 2mls in each ass cheek twice a week, or go with 4 mls, in each cheek once a week.
Why not use the quads, delts, bi's etc...? They work just the same and they are easier to inject into in my opinion. I can't reach back there anyway..ha ha.