8. Chris Benoit
How do we know? Autopsy results, the police search of his house, investigations into various corrupt doctors and pharmacies. As crazy as it sounds, it was not uncommon to see internet discussions where Chris Benoit fans would argue that he was clean and his physique was attainable without chemical help. He barely looked human at times late in his life. It's would be almost laughable now if the circumstances weren't so horrifically sad. Have you SEEN how he looked, especially in the latter part of his career/life? That is not a physique that can be obtained through diet and exercise. Everyone figured he was a big steroid abuser, we just didn't know how big. After his death, it came out that Benoit was known to the U.S. Drug Enforcement Administration (DEA) as someone who bought unusually large quantities of steroids from a number of suppliers under investigation. Think about that for a second: He was not a dealer. He was a user. He was such a big user, though, that was on the radar of the DEA as a person of interest. That's mind boggling.