(CNN) -- Now-disgraced cyclist Lance Armstrong says he used an array of performance enhancing drugs -- including EPO, testosterone and human growth hormone -- to win seven Tour de France titles followed by years of often angry denials.

"This is too late, it's too late for probably most people. And that's my fault," he said. "(This was) one big lie, that I repeated a lot of times."

EPO, or erythropoietin, is a hormone naturally produced by human kidneys to stimulate red blood cell production, according to the World Anti-Doping Agency. Cyclists and other athletes use EPO to raise their red blood cell counts, which increases the amount of oxygen that can be delivered to muscles, improving recovery and endurance.

Armstrong admitted to Oprah Winfrey that, in addition to using drugs, he undertook blood transfusions to get ahead. He said it was needed to win, saying that while he didn't invent the culture of doping, he didn't do enough to prevent it.

"I lost myself in all of that," he said. "I was used to controlling everything in my life."

The first installment in his interview, which was conducted earlier this week with the talk-show host, aired Thursday on the OWN cable network and on the Internet. The second and final installment will be broadcast Friday night.

The apology was not unexpected. On Tuesday, Winfrey appeared to confirm widespread media reports Tuesday the longtime champ admitted to her that he'd doped and lied about it.

Armstrong's history of alleged doping has tarred the cancer charity Livestrong that he founded, as well as tarnished his once glowing reputation as a sports hero.

Those who spoke out against Armstrong at the height of his power and popularity not only felt his wrath, but the wrath of an adoring public.

Now, with Armstrong stripped of endorsement deals and his titles, those who did speak out are feeling vindicated.

"Eleven years of bullying and threats," Kathy LeMond, the wife of cyclist Greg LeMond -- one of Armstrong's earliest targets -- wrote on Twitter. "LA is now the Greatest Fraud in the History of Sports."

Armstrong stripped of Olympic bronze

Not only is Armstrong no longer officially a Tour de France winner -- he's no longer an Olympic medalist, either.

The International Olympic Committee has stripped Armstrong of the bronze medal he won in the men's individual time trial at the 2000 Olympic Games and asked him to return the award, an IOC spokesman said Thursday. The committee has not yet decided whether to bestow the bronze on fourth-place finisher Abraham Olano of Spain or to leave the slot vacant, IOC spokesman Andrew Mitchell told CNN.

In October, the International Cycling Union stripped Armstrong of his Tour de France titles. Armstrong responded a few weeks later by tweeting a photo of himself lying on a sofa in his lounge beneath the seven framed yellow jerseys from those victories.

The International Olympic Committee said in October that it was reviewing evidence against him.

Armstrong competed in two events in the 2000 games in Sydney, Australia -- the men's individual time trial, where he medaled, and the men's individual road race, where he finished 13th. He is retroactively disqualified in both races, the IOC said.

"We have written to Armstrong asking him to return the medal" and informed the U.S. Olympic Committee, Mark Adams, another IOC spokesman, said Thursday. It's up to the U.S. committee to handle retrieving the medal from Armstrong, the IOC said.

The decision was made "in principle" at a meeting of the IOC executive board in December, Adams said. The committee did not act on the decision until it received confirmation from the International Cycling Union that Armstrong was not appealing that agency's decision.

The USOC was notified Wednesday that the IOC wants the medal back, USOC spokesman Patrick Sandusky said.

"We will shortly be asking Mr. Armstrong to return his medal to us, so that we can return it to the IOC."

Deadline for Justice Department to join lawsuit

Thursday was also the deadline for the Justice Department to decide whether to intervene in a federal whistleblower lawsuit filed by former Armstrong teammate Floyd Landis, a source familiar with the matter told CNN. The source said the department and Armstrong's lawyers were in talks regarding the case, but Armstrong lawyer Robert Luskin would not comment on any reported talks Thursday.

"We remain hopeful there will be an agreed resolution," Luskin told CNN.

Landis, the 2006 Tour de France winner, lost his title for doping and is among those accusing Armstrong of taking banned substances while leading the U.S. Postal Service cycling team. His lawsuit accuses accuses the team's former management of defrauding the government of millions of sponsorship dollars because the team management knew about the drug use and didn't do anything.

The New York Times reported earlier this week that Armstrong has been considering testifying against others to help his own situation, but Luskin denied that allegation.

"There is no truth at all to any suggestion that Lance is trying to limit his own liability by implicating others, and that remains true," he said.Lance Armstrong Admits Using Performance-Enhancing Drugs