Apparently in a tell all book, Zach Morris juiced it up for his short Saved By the Bell : College Years stint. I say these allegations are true. Check out the Nasser like delts on him.
Who's doing the tell all, the disgruntled Dustin Diamond?
If you saw "Saved By the Bell: The College Years", you clearly can see that Zach Morris was actually BIGGER than AC Slater (who's supposed to be the high school/college jock).
I don't see what the need for him to take steroids would be. He wasn't the athlete of the show.