Light-heavyweight Muhammed “King Mo” Lawal has been accused of taking a banned substance.

A urine sample provided by Lawal for his Jan. 7 fight in Las Vegas showed the presence of the anabolic steroid drostanlone, the Nevada Athletic Commission said.

“Both of us are very surprised by these results,” Kogan told USA TODAY. “Neither of us has ever heard of this drug. … We honestly have no clue where this came from.”