3. Davey Boy Smith
How do we know? Medical examiner declared long-term steroid use a contributing cause in his death. A teenager who idolized his cousin Dynamite Kid, he followed in his footsteps as a wrestler, even training with the same older wrestler, Ted Betley. Like Dynamite, Davey became a star on TV back home, and it led to him joining his cousin in Calgary. While Davey was taller than Dynamite with a more hulking frame, he was still a skinny kid, and his cousin injected him with steroids to help him get bigger. Like with Dynamite, it's easy to spot when Davey started using. After Dynamite brought Davey to Japan, they became international superstars as spark plug powerhouses who moved like acrobats. Eventually they split for good, and Davey, who got way too big, went back to the WWF. His feud with The Warlord was a black mark on his career, almost the definitive example of two swollen steroid guys having awful matches together. He eventually shed some weight and got some of his groove back, but he never fully regained his form.