I expect that most pro athletes are cheating with their supplements.
Where are the incentives? The incentives are massively in the direction of cheating. The chances of getting caught are low.
People react to incentives. If the incentives are strong to cheat, most people will cheat.
The best way to defeat the urge to cheat is with a homogeneous society that values honesty. That’s not the United States today. It was at one time.
In some classes I took at school, cheating was rampant. In other classes, it never happened to my knowledge. Every class had a tone and you quickly learned what was acceptable.
Few sports journalists have any stomach for investigating these matters. Most reporters don’t particularly like reporting. They prefer to simply shape the facts they are spoonfed.