Olympic and world 400m champion LaShawn Merritt has failed three doping tests for a banned substance and accepted a provisional suspension, his lawyer said Thursday. “LaShawn Merritt has accepted a provisional suspension as a result of positive drug tests caused by his use of an over-the-counter male enhancement product,” the American athlete's attorney Howard Jacobs said in a statement. The statement said Merritt had used the product, which contained DHEA and pregnenolone, following the 2009 season. “(It) caused LaShawn Merritt to test positive on three successive tests in October 2009, December 2009, and January 2010,” the statement said. Should the 23-year-old receive a standard two-year suspension, it would prevent him defending his world title next year and would seriously hamper his preparations for the 2012 Olympics. Merritt won individual 400 metres gold at the 2008 Olympics and 2009 world championships and led the US to victory in the 4x400 meters relay in both competitions. His victory by almost a second over defending champion and favorite Jeremy Wariner at the Beijing Games was the largest winning margin in the event for over 100 years. Merritt was not notified of the positive tests until March. “To know that I've tested positive as a result of product that I used for personal reasons is extremely difficult to wrap my hands around,” the 23-year-old Merritt said in a separate statement. “I hope my sponsors, family, friends and the sport itself will forgive me for making such a foolish, immature and egotistical mistake. “Any penalty that I may receive for my action will not overshadow the embarrassment and humiliation that I feel inside,” the 2009 world champion said. USA Track and Field CEO Doug Logan said in a release he was “disgusted by this entire episode.” “He has now put his entire career under a cloud and in the process made himself the object of jokes,” Logan said. “In this day and age, a professional athlete should know better.” Typically, an athlete hit with a first-time doping violation receives a two-year suspension and forfeits any results from the time when he doped. USADA does have a precedent of giving more favorable terms to athletes who cooperate.