Well, this isn't a great source but they say it is available by prescription only. For the purpose of this discussion I think this might be the best answer. It is from 12/1/12
Is HGH Illegal? | eHow.com
So, I guess in that sense the NFL should treat it like Adderall. Without an Rx it should be banned. I do believe players should be able to use it to speed up recovery from injuries.
I'd be okay with that. Unfortunately, they still need to agree on a fair way to test it.