BJ Penn recently stepped out of semi-retirement to fight up and coming welterweight star Rory MacDonald and now he’s raised the ante higher by challenging him to a stringent pre-fight drug testing procedure.

“VADA anti-doping has offered to sponsor our upcoming fight.I’ve accepted and invite you to help me clean up the sport,” Penn wrote to MacDonald on Twitter.

“VADA results will be released after the fight to ensure that the fight happens. Lets get started asap!!”

If the 22 year-old MacDonald, who’s a training partner of Penn’s old rival Georges St.Pierre and is tipped by him to be a future title holder at 170lbs, was concerned by the challenge then he made no sign of it as he quickly responded to Penn and agreed to go along with his plan.

“already worried BJ? honestly i think its a great idea 2, and im ready to do the testing for our fight aswell,” MacDonald replied.

All too often lately there’s been bad news stories about fighter’s failing drugs tests so this is a nice twist in the tail and could provide a bit of positive publicity if it all goes according to plan.

Interestingly, other fighters who’ve been lined to PED’s in the past are currently attempting to distance themselves from the issue. Nate Marquardt was the first, stating that he was going to stop using Testosterone Replacement Therapy despite having a doctor’s exemption to use it, as has former WEC fighter Shane Roller.

Earlier this week Alistair Overeem also revealed that he is now taking a series of random drugs tests to prove to everyone that he is “clean” after failing a test earlier in the year.

The thorny issue of PED’s in MMA isn’t likely to go away anytime soon though, with the likes of Chael Sonnen and Frank Mir having been given TRT exemptions recently, while even Rich Franklin admitted in a recent interview that he has considered the possibility of doing so to prolong his career, though he is not currently doing so.