Seven-time Tour de France winner Lance Armstrong has announced he will not fight the charges filed against him by the US Anti-Doping Agency (USADA).
American Armstrong said in a statement on his personal website that he is "finished with this nonsense" and insisted he is innocent.
"There comes a point in every man's life when he has to say, 'Enough is enough'. For me, that time is now," he said. "I have been dealing with claims that I cheated and had an unfair advantage in winning my seven Tours since 1999."
The 40-year-old has always denied claims he ever used performance-enhancing drugs during his career but USADA chief executive Travis T. Tygart has said Armstrong should face the same proceedings as any other athlete charged with doping offences.
Armstrong, who was charged in June, sought a temporary restraining order against the agency's legal action but that was dismissed in a federal court in Austin, Texas on Monday.
His statement added: "If I thought for one moment that by participating in USADA's process, I could confront these allegations in a fair setting and - once and for all - put these charges to rest, I would jump at the chance.
"But I refuse to participate in a process that is so one-sided and unfair. Regardless of what Travis Tygart says, there is zero physical evidence to support his outlandish and heinous claims."
Responding to Armstrong's statement, USADA chief executive Tygart said: "It is a sad day for all of us who love sport and our athletic heroes."
While Armstrong remains steadfast that he did not cheat, Tygart sees the case in a different light.
Tygart added in a statement released by USADA: "This is a heartbreaking example of how the win-at-all-costs culture of sport, if left unchecked, will overtake fair, safe and honest competition, but for clean athletes, it is a reassuring reminder that there is hope for future generations to compete on a level playing field without the use of performance-enhancing drugs."