What happens if you`re on steroids will your body just get bigger, like fatter or more muscular indeed?

No: There are two types of steroids. Anabolic Steroids can when combined with exercise and diet cause rapid muscle growth. The problem with "juicing" is that it leads to a lot of serious problems later on. Cancer is one of them. Arnold Schwarzenegger, many times Mr. Universe, never used any drugs to train and today enjoys excellent health. Do the work. Eat right. Skip the juice. Good luck!