Disgraced cyclist Lance Armstrong has confessed to using a "cocktail" of performance enhancing drugs to win his record seven Tour de France titles.

In the first instalment of his two-part interview with talk show queen Oprah Winfrey, Armstrong admitted to using banned substances including EPO, testosterone, steroids and human growth hormone, as well "blood doping".

Armstrong, 41, gave a calm and seemingly remorseless account of his career as a drug cheat, blaming a "ruthless desire to win" for his decision to dope.

He said he didn't feel bad about his drug use because he didn't feel like he was cheating as so many of his competitors were also allegedly doping.

"I didn't have access to anything that no one else did," he said. "It was as common as putting air in your tyres."

Armstrong also said he wasn't afraid of being caught because drug-testing was so primitive in the 1990s.

"Drug testing has changed, it's evolved," he said. "In the old days they tested at the races. They didn't come to your home. And there was no testing out of competition."

Armstrong has always furiously denied claims he used illegal drugs, even suing people and publications who suggested otherwise.

Today, he admitted he'd been lying and apologised.

"I'm a flawed character," he said. "All the blame falls on me. While I've lived through this process … I know the truth, the truth is out there and it isn't what I said (previously).

"And I'm sitting here today to acknowledge that and to say I'm sorry for that. I view this situation as one big lie that I repeated a lot of times."