In 2012, a United States Anti-Doping Agency (USADA) investigation concluded that Armstrong had used performance-enhancing drugs over the course of his career[6] and named him as the ringleader of "the most sophisticated, professionalized and successful doping program that sport has ever seen".

In April 2018, Armstrong settled a civil lawsuit with the United States Department of Justice and agreed to pay US$5 million to the U.S. government after whistleblower proceedings were commenced by Floyd Landis, a former team member.

[15] In the 1987–1988 Tri-Fed/Texas ("Tri-Fed" was the former name of USA Triathlon), Armstrong was ranked the number-one triathlete in the 19-and-under group; second place was Chann McRae, who became a US Postal Service cycling teammate and the 2002 USPRO national champion.

[citation needed] In a 2016 speech to University of Colorado, Boulder professor Roger A. Pielke Jr.'s Introduction to Sports Governance class, Armstrong stated that he began doping in "late spring of 1995.

[24] Armstrong visited urologist Jim Reeves in Austin, Texas, for diagnosis of his symptoms, including a headache, blurred vision, coughing up blood, and a swollen testicle.

[31] On October 25,[32] his brain lesions, which were found to contain extensive necrosis, were surgically removed by Scott A. Shapiro,[33] a professor of neurosurgery at Indiana University.

[34] In January 1997, Armstrong unexpectedly appeared at the first training camp of the Cofidis team at Lille, France, riding 100 km (62 mi) with his new teammates before returning to the United States.

Greg LeMond, Irish cycling legend Sean Kelly, and five time Tour champion Miguel Induráin were the most important cyclists at the event.

[47] During stage eleven and twelve of this Tour is when the race was won as US Postal had Vuelta champ Roberto Heras lead Armstrong up both climbs, breaking the peloton in the process.

The individual time trial on stage 16 up Alpe d'Huez was won in style by Armstrong as he passed Ivan Basso on the way despite having set out two minutes after the Italian.

In the mountain stages, Armstrong's lead was attacked multiple times mostly by Ivan Basso, but also by T-mobile leaders Jan Ullrich, Andreas Klöden and Alexandre Vinokourov and former teammate Levi Leipheimer.

To complete his record-breaking feat, he crossed the line on the Champs-Élysées on July 24 to win his seventh consecutive Tour, finishing 4m 40s ahead of Basso, with Ullrich third.

[72] For example, rather than having the frame, handlebars, and tires designed and developed by separate companies with little interaction, his teams adopted a Formula One relationship with sponsors and suppliers named "F-One",[73] taking full advantage of the combined resources of several organizations working in close communication.

[97] The newspaper's lawyers issued the statement: "The Sunday Times has confirmed to Mr. Armstrong that it never intended to accuse him of being guilty of taking any performance-enhancing drugs and sincerely apologized for any such impression."

The same authors (Pierre Ballester and David Walsh) subsequently published L.A. Official and Le Sale Tour (The Dirty Trick), further pressing their claims that Armstrong used performance-enhancing drugs throughout his career.

[citation needed] On March 31, 2005, Mike Anderson filed a brief[98] in Travis County District Court in Texas, as part of a legal battle following his termination in November 2004 as an employee of Armstrong.

Vrijman was head of the Dutch anti-doping agency for ten years; since then he has worked as a defense attorney defending high-profile athletes against doping charges.

[110][111] The report said tests on urine samples were conducted improperly and fell so short of scientific standards that it was "completely irresponsible" to suggest they "constitute evidence of anything".

"[115] In June 2006, French newspaper Le Monde reported claims by Betsy and Frankie Andreu during a deposition that Armstrong had admitted to using performance-enhancing drugs to his physician just after brain surgery in 1996.

"[116] Armstrong suggested Betsy Andreu may have been confused by possible mention of his post-operative treatment, which included steroids and EPO that are taken to counteract wasting and red-blood-cell-destroying effects of intensive chemotherapy.

[120] From the Los Angeles Times article: "The results, Australian researcher Michael Ashenden testified in Dallas, show Armstrong's levels rising and falling, consistent with a series of injections during the Tour.

Ashenden, a paid expert retained by SCA Promotions, told arbitrators that the results painted a "compelling picture" that the world's most famous cyclist "used EPO in the '99 Tour".

[121] The SCA trial was settled out of court, and the Los Angeles Times reported: "Though no verdict or finding of facts was rendered, Armstrong called the outcome proof that the doping allegations were baseless."

"[121] In October 2012, following the publication of the USADA reasoned decision, SCA Promotions announced its intention to recoup the monies paid to Armstrong totaling in excess of $7 million.

[137] In June 2012, the United States Anti-Doping Agency (USADA) accused Armstrong of doping and trafficking of drugs, based on blood samples from 2009 and 2010, and testimony from witnesses including former teammates.

As nearly all national and international sporting federations, including UCI, follow the World Anti-Doping Code, this effectively ended his competitive cycling career.

[145] In the aftermath of Armstrong's fall from grace, a CNN article wrote that, "The epic downfall of cycling's star, once an idolized icon of millions around the globe, stands out in the history of professional sports.

[147][148] In 2010, one of Armstrong's former teammates, the American Floyd Landis, whose 2006 Tour de France victory was nullified after a positive doping test, sent a series of emails to cycling officials and sponsors admitting to, and detailing, his systematic use of performance-enhancing drugs during his career.

In 2007, Armstrong with Andre Agassi, Muhammad Ali, Warrick Dunn, Jeff Gordon, Mia Hamm, Tony Hawk, Andrea Jaeger, Jackie Joyner-Kersee, Mario Lemieux, Alonzo Mourning, and Cal Ripken Jr. founded Athletes for Hope, a charity that helps professional athletes become involved in charitable causes and aims to inspire non-athletes to volunteer and support the community.

However, the June suspension by USADA and eventual ban by WADA prohibited Armstrong from further racing Ironman branded events due to World Triathlon Corporation anti-doping policies.