DISGRACED American cyclist Lance Armstrong has admitted taking banned substances, including blood-boosting agent EPO, to help win the Tour de France.

After years of denials, the 41-year-old told talk show host Oprah Winfrey that he doped during his cycling career.

In an explosive start to the much-anticipated interview, Armstrong confirmed he doped during all seven of his Tour de France wins, from 1999 to 2005, and admitted he used EPO.

He also conceded he "blood doped", used blood transfusions and took banned substances like testosterone, cortisone and human growth hormone.

Armstrong told Winfrey that at the time of his drug-taking it did not feel wrong, he did not feel bad about it and that he did not feel it was cheating, as he was creating a level playing field with other riders who took drugs.

But he said he had now changed his opinion, telling her: "I'll spend the rest of my life trying to earn back trust and trying to apologise to people.

"For the rest of my life. I see the anger in people. And betrayal. It's all there. These are people that supported me, believed in me. They have every right to feel betrayed. And it's my fault. I will spend the rest of my life trying to earn back trust and apologise to people."

He added: "I'm happier today than I was then."

Armstrong said he believed that doping was necessary to win the Tour de France. He said: "That's like saying we have to have air in our tyres or water in our bottles.

"It was part of the job. I don't want to make any excuses, but that was my view and I made those decisions."