In an interview with talk show host Oprah Winfrey broadcast Thursday night, Armstrong ended years of denial by admitting he started using drugs in the "mid 1990s", reports Xinhua.
"Yes", said the 41-year-old American without hesitation when Winfrey asked whether he used performance enhancing drugs.
"My cocktail, so to speak, was only EPO, but not a lot, transfusions and testosterone," he said.
Asked why he had repeatedly denied using banned drugs until now, Armstrong said: "I don't know I have a great answer.
"This is too late, probably for most people, and that's my fault. I view this situation as one big lie that I repeated a lot of times," he said.
Armstrong, whose successful fight against testicular cancer and feats in cycling once inspired millions of people, said he just followed a "doping culture".
"I didn't invent the culture, but I didn't try to stop the culture," he said. "I'm sorry for that."
Armstrong said he never considered he did something wrong at that time and he would not have won seven Tour de France if not for doping.
"I just looked up the definition of cheat. And the definition of cheat is to gain an advantage on a rival or foe, you know, that they don't have or that they -- you know, I didn't feel it that way. I viewed it as a level playing field," he said.
Since his return from cancer in 1998, Armstrong started to conquer the toughest cycling race Tour de France in 1999, Armstrong showed such strong will and longing to win that he took to pills and injections and even pressured his teammates to do so.
Armstrong said fighting cancer could be the reason that he turned from a normal competitor to a "ruthless" one and a "bully".
"I grew up as a fighter. Before my diagnosis, I was a competitor, but not a fierce one."
But with the 1996 diagnosis of cancer, Armstrong was met with a situation that he could not control the outcome for the first time. He needed to fight it "ruthlessly and relentlessly" and to "win it at all cost".
And then he took the attitude to the cycling course, "That's bad," he said. "I wasn't a bully before that."
While confessing to cheating and bullying, he denied several of the other accusations that have been made against him.
He rejected suggestions that he tried to cover up a positive doping test at the 2001 Tour Of Switzerland by paying the International Cycling Union (UCI).
"That story isn't true. There was no positive test. No paying off of the lab. There was no secret meeting. That did not happen. I'm no fan of UCI," he said.
Then he said his donation to the UCI wasn't voluntary.
"They asked me to (make the donation)," he said.
Armstrong has seen all his competition results cancelled dating back to August 1998 and has been banned for life. He lost almost all his corporate sponsors and stepped down from the board of the cancer charity Livestrong he founded in 1997.
But there are more troubles waiting.
Hours before the interview went on air, the International Olympic Committee (IOC) stripped him of the bronze medal he won at the 2000 Sydney Games.
The Sunday Times newspaper is suing for the return of their $500,000 paid to settle their case with Armstrong in 2004 when the London-base newspapers made allegations on his doping.
Insurance company SCA, sued by Armstrong when they withheld a $five million bonus after his sixth Tour win in 2004 because of doping allegations, now wants that money back.
The government of South Australia state is going to seek the repayment of several million dollars in appearance fees paid to Armstrong for competing in the Tour Down Under cycle race in 2009, 2010 and 2011.
