Billy Joe Saunders has insisted he is a "clean athlete" following confirmation from the British Boxing Board of Control that he was "not in breach of BBBofC or UKAD anti-doping regulations".
Less than a month before Saunders is due to defend his WBO world middleweight title against Demetrius Andrade, reports emerged of an "adverse analytical finding" in a drugs test.
However, promoter Frank Warren said a nasal spray product that Saunders had used is permitted "out of competition" and that the 29-year-old fighter was not in breach of any BBBofC or United Kingdom Anti-Doping regulations.
In a statement, Warren said: "Following reports of an adverse analytical finding in a test carried out by the Voluntary Anti-Doping Association (VADA) on WBO world middleweight champion, Billy Joe Saunders, we can confirm that the product concerned is permitted to be used 'out of competition' by United Kingdom Anti-Doping (UKAD) in line with the regulations of the World Anti-Doping Agency (WADA).
"For the avoidance of doubt, the product in question was a common decongestant nasal spray.
"The British Boxing Board of Control (BBBofC) under whose jurisdiction Billy Joe Saunders is licensed are affiliated only to UKAD/WADA.
"Today the BBBofC have confirmed that Mr Saunders is not in breach of BBBofC or UKAD anti-doping regulations and is therefore in good standing and is licensed to box and defend his world title on 20 October.
"Mr Saunders has been tested a number of times in 2018, all negative, his last out of competition test by UKAD was on 24th September 2018."
Saunders wrote on his official Twitter account on Thursday night: "Thank you to my fans who stick by me I'm a clean athlete and gonna be around a long time thank you all stay blessed."
Saunders is due to defend his WBO world middleweight belt against Andrade in Boston on 20 October.
That title defence will be in the hands of the Massachusetts State Athletic Commission.
Earlier this week, Saunders was fined £100,000 and given a severe reprimand about his future conduct after video footage emerged of him appearing to offer a woman drugs.
Saunders' actions were filmed from his car and seemingly show him offering £150 worth of drugs to the woman to perform a sex act as well as asking her to punch a passer-by, which she does, before he drives off.
He was hit with a misconduct charge by the BBBofC, which found Saunders guilty of bringing the sport into disrepute at a hearing on Tuesday.