Amir Khan fears doping may be rife in boxing as he demands more stringent testing across the board following a number of recent scandals.

The British light-welterweight saw his hopes of avenging a controversial December defeat by Lamont Peterson scuppered when the new WBA and IBF champion tested positive for a banned substance ahead of their May rematch.

Peterson's use of synthetic testosterone - which he claims is for medical reasons - is one of a number of recent doping-related scandals within the sport.

Elite fighters such as Andre Berto and Antonio Tarver have also been caught out recently, while British heavyweight Larry Olubamiwo was banned for multiple violations.

Londoner Olubamiwo claimed drug-taking is commonplace and Khan fears he could be right.

The Bolton fighter, who challenges Danny Garcia for the WBC title in Las Vegas on Saturday, while also hoping to reclaim his old WBA belt, believes more needs to be done to combat the problem.

"I hope the situation does clean itself up. Berto is another fighter who just got caught. All these fighters are getting caught," said Khan.

"There are a lot of fighters out there who might be taking it. You never know. But at least it makes people realise this is a serious matter and if they do get caught, they will get banned."

Referring to Peterson's test, the 2004 Olympic silver medallist said: "Imagine me taking something like that. I'd be an animal.

"We need to clean up sport and that is what's happening now. Since the Lamont Peterson issue, so many fighters have been caught.

"Lamont was the first guy to get caught recently and then since then we've had Andre Berto, Antonio Tarver and people like that. We've had top-class world champions and former world champions being caught.

"It's bad. How many other people are on this stuff? You just don't know."

Ironically, Peterson - who beat Khan by split decision in December - had demanded more stringent testing for the rematch, while the likes of Floyd Mayweather and Nonito Donaire advocate methods such as out-of-competition testing and blood sampling.

"Nonito Donaire and Floyd are showing the way, saying 'we'll do tests throughout the year'," Khan said.

"They can test me too because in the UK we do that, they test me even during my time off. I always have to tell the professional board where I'm going to be and they can come and test me any time randomly.

"It's happened to me four or five times already. I think every fighter should be tested outside of competition."

Garcia, meanwhile, is just relishing the chance to defend the belt he won by dethroning Mexican legend Erik Morales.

"It's a dream come true," said the Philadelphian.

"I'm enjoying every minute, from the press and media to meeting the fans and I'm ready to give them a great fight.

"After winning the title you have to stay on top of your game because it's hard to win but even harder to keep it.

"I'm ready to show the world who is best."