Damn straight. If you don't think you can do it, you won't.
Heh. I don't really take any supplements either. I tried Surge; I guess it was slightly helpful. It was hard to tell since my training was all f'd up during that time anyway. I did recently purchase some of that Grow! protein powder from here, mostly for convenience purposes -- quick and easy protein source at work.
Real food works for me: lots of chicken, oatmeal, eggs, and cottage cheese (which I've come to enjoy).
Ya know, I don't even know what my 1 rm's are. Last I tried that I pressed 200 and squatted 225 a few times. Heh. Maybe I'll give it a go right before I switch programs: which hopefully won't be soon, cuz switching programs means I stalled on my current 5x5 routine.
What's your lifting schedule like?