Former British Cycling and Team Sky doctor Richard Freeman has admitted destroying a package of the banned substance testosterone in 2011 as his medical tribunal resumed this week.
Freeman told a hearing in Manchester that he was unable to explain his motive for destroying the product after being ordered to remove it from British Cycling's headquarters by his then-boss, former medical director Steve Peters.
He denied "knowing or believing" the testosterone gel was to be administered to an athlete to improve their performance, asserting he was bullied into ordering it by Shane Sutton, the former technical director at British Cycling and Team Sky head coach, in order to treat erectile dysfunction.
Sutton has strenuously denied both claims.
Simon Jackson, cross-examining for the General Medical Council, said: "I am going to suggest that you never said that in three witness statements or any previous interview that you destroyed it that night - why is that?"
Freeman responded: "I don't have an answer for that. I took it home that night, this is my regret that I keep playing again and again, I decided to destroy it. I had no thought of an audit trail."
Freeman has previously admitted 18 of 22 charges, which include ordering 30 sachets of testosterone gel to the Manchester velodrome nine years ago and lying to British Cycling and UK Anti-Doping about making the order.
His Medical Practitioners Tribunal Service (MPTS) hearing resumed this week after it was adjourned in December last year on medical grounds.
On the second day of giving evidence, on Wednesday, Freeman admitted he had not read the "small-print" in the World Anti-Doping Agency's code, which prohibits athlete support staff from possessing banned substances unless in exceptional circumstances.
Jackson said the WADA rules establish "that if you have it, you are deemed to be in possession of it, unless you have an acceptable justification".
He added: "It would not include buying a substance or buying it for a friend. You did not have justifiable medical circumstances to be in possession."
Freeman, who could lose his medical licence, said: "I admit to poor medical judgement. I was getting, ordering and prescribing the Testogel for a man I considered my patient.
"I knew the WADA code existed and I knew the sections on the types of drugs that were banned and the methods and that was updated every year.
"My knowledge on that was very good. I have to confess I had no knowledge of and I had not read the small print on possession of prohibited substances and prohibited methods -- that never occurred to me."