Former UFC lightweight and welterweight champion BJ Penn has vowed not to give up on his desire to compete in the Octagon again, despite facing a suspension for using an IV infusion without prior permission from USADA.

In a new interview in his native Hawaii, the 37 year-old Penn gave his side of the story, confirming that he told USADA about an IV he’d had a week prior to his random drug test, unaware that it was going to get him into trouble.

“I wasn’t aware that I couldn’t take an IV 365 days a year,” Penn told Hawaii’s KHON2 News yesterday. “I got an IV back in March and USADA came to do a test. We did the test and they asked me, when was the last time I got an IV. I told them ‘the week before’ and that’s it. We’re not being investigated for any banned substances or nothing like that. It’s just [that] I disclosed to USADA that I did an IV without getting permission from them first and they penalized me for it.”

The fact that Penn’s now been pulled from his UFC 199 fight with Cole Miller and is likely to face some kind of suspension may seem harsh given that it’s only an IV and not a performance enhancing drug, but USADA have stressed that an important reason they are clamping down on the use of it is that some athletes have used the process to alter the accuracy of blood and urine test results, as well as to flush illegal drugs from their systems faster.

Nevertheless, Penn feels that he’s done little wrong, and is confident that his lack of understanding regarding the rules won’t result in a lengthy suspension.

“I don’t think it should be so long. I don’t think it should be too long because, I mean ignorance of the rule is no excuse but it has nothing to do with banned substances. We’re not doing anything with any performance enhancement. I think they’ve just gotta lay down the punishment for whatever they feel.”

Penn also made it clear that he’s still eager to compete again, and hinted that his coach Greg Jackson, was also backing him.

“I’m the best I’ve ever been. I’m doing great in the gym. I feel awesome. I don’t think Greg Jackson would let me quit at this point.”