I guess that term has a stronger connotation in the UK. In the US "meathead" is said almost affectionately, as in "what's up my fellow meatheads?".
OP, you are no where near your genetic potential. Supplements are only a very tiny percentage of the bodybuilding equation. You need to get your diet and/or training in order first. No amount of steroids are going to help you put on muscle if your diet isn't right.