How long have you been lifting?
Diet, type of training, etc?
At 6' 170, you either need to learn how to train properly or how to eat (or both). I can say this with confidence because that is exactly where I was until I learned how to eat properly. Lifted consistently for 3-4 years, gained about 5 pounds until I figured out I wasn't eating enough. Added a snack/meal mid-morning and mid-afternoon along with making sure I ate breakfast and put on 20 pounds in 4 months. No exaggeration.
Steroids won't fix a crap diet or bad training plan. Fix those first, put in another year or so of solid training (at a minimum) before you start messing with gear.