Just more paper work wrote:
"He admitted that though he was taking several supplements, he did not declare any of them on his doping control form."
Indeed, that can always be "back-dated" if necessary. What's the point in even having the space on the DC form in the first place, as no one takes it seriously (except NOP it seems).
It is in no way mandatory to put down any supplements at all on your doping control form.
My understanding is that if you put down a supplement and end up with a positive sample you can then claim a "tainted supplement" excuse. You would need more than just that to win, but if you do not put a supplement down on your DC, you basically forfeit a tainted supplement claim.
This also came into play during the Sharapova appeal. The fact that she did not put down meldonium on her doping control form (it includes meds as well as supplements) was taken as evidence that she was concealing and taking it for the purpose of performance enhancement.