Steve: I didn’t think it’d bother me this much. I’ve always prided myself on not relying on artificial improvements. Always tried to stay in peak shape through nothing more exotic than hard work and now I’ve lost that forever. 
Tony: Steve, listen to me. I’ve wrestled with the same questions you’re asking yourself now many times.
Steve: Tony, I didn’t mean -
Tony: I know you didn’t. My point is a man’s worth isn’t measured by what he’s made of, by blood or bone. It’s what’s inside, what you believe, and how you act on those beliefs, that counts. And by that yard stick — I doubt anything could diminish you.

From Iron Man v1 #314