What types of steroids did Jason do?

Part 3 takes place a day after Part 2 and Jason bulked up a good 20-30 pounds, grew a few inches, and found time to get a haircut in the span of about 24 hours. Those must have been quite the steroids.

It's also an interesting insight into Jason's character that he still wants be somewhat well-groomed while he goes out to murder teenagers. Jason must know that nobody really gives a shit what his hair looks like. Really shows that deep down he has some type of human feelings instead of just feral instincts such as eating dogs and licking roadkill.