Right now he is a top 5 QB. When Cam Newton and Matt Ryan won their MVPs they were top 5 QBs at those times. Why is that so difficult to admit? Right now Peyton Manning is not a top 5 QB. When he was on the Colts for most of his seasons he was.
This isn't an all time list, it's a right now list and right now if he does not play another down in the NFL at this very moment Patrick Mahomes is a top 5 QB and every general manager in the NFL would agree.
It is in every players contract and NFL rules player abides by. The player alone is responsible for everything in his body. Cannot plead ignorance. If a player is unsure about something, consult the team physician or just do not take it. No matter the circumstance of occurrence, if any of these (or another substance that eventually breaks down into one of these) listed substances are detected, it is a violation of the NFL Performance Enhancing Substance (PES) policy and player is subject to suspension.
It is long, thorough list (SARMS is on it at the bottom) -
As far as SARMS, many contain unlisted and illegal drugs (Nov. 28, 2017 JAMA article) as well -
Chemical analyses of 44 products sold via the internet as selective androgen receptor modulators revealed that only 52% contained selective androgen receptor modulators and another 39% contained another unapproved drug. In addition, 25% of products contained substances not listed on the label, 9% did not contain an active substance, and 59% contained substance amounts that differed from the label.
Meaning Selective androgen receptor modulators, which have not been approved by the US Food and Drug Administration, were available through the internet and were inaccurately labeled."