10 Grim Realities Of Superhero Origins
2. Captain America, Steroid Addict

It was a success, and the weedy kid was transformed into the muscle-bound, bulletproof paragon of patriotism, Captain America, who helped turned the tide of war with both his superpowers and as a propaganda tool. Then he got frozen and thawed out in the sixties to join the Avengers, but that's another story.
The grim reality: The real-life US military is actually working on creating "super soldiers", tinkering with things like gene therapy (which you may recognise from Metal Gear Solid, a game full of so much ridiculous stuff it kinda overshadows the actual science they throw in there) and considering the use of robot suits and the like in warfare. Back in the thirties, however, the super soldier serum that turned Steve Rogers into Captain America would've had more in common with your garden variety anabolic steroid.
Like wrestlers, body builders, and Carrot Top use. Which means that whilst he would be pretty strong for a while, he'd get dependant on constant doses of the stuff, and eventually his muscles who atrophy and wither and die. Also he'd have a tiny winkle, apparently.