Definitely believable. Obviously can't say for sure but the guy was 225 pounds when he was 10 years old. Was squatting 600 pounds when he was 15. Only ever competed in drug tested federations and meets. And because he was on the Olympic team from 92 - 96 was subject to random drug tests by the US Olympic committee. And he was very open about other countries athletes using drugs at the 96 Olympics and said he would quit the sport afterwards because of it, which he did.
Like I said, you can't prove he was or wasn't but I wouldn't be surprised at all if he wasn't. In fact I'd be more surprised if he was using drugs during his career.
He was a genetic beast no doubt. But so is every elite strength athlete.
Its not like Henry would have been the first PED using athlete to have passed multiple tests. Nor would he the first PED using athlete to openly take an anti-drug stance.

Did he quit Olympic lifting because of the drug usage or because it wasn't his strongest field? I'd guess the latter even if Henry claimed the former.
Fact is the guy competed against the juiced the gills, genetic elite and often came up on top. Not to mention later becoming a pro wrestler where gear use is almost a requirement due to the intensity of the profession.
Overall, I find it very difficult to believe he did all this without so much as even a few orals in his system.
Could he have been natural? I guess so. Stranger things have happened.
Do I think he was natural? Hell no!
