In an interview with Le Monde, a newspaper he used to scorn, Armstrong claimed it was impossible in his era to win cycling's showcase race without doping.
The publication of his comments comes one day before the 100th Tour starts on the French island of Corsica.
Armstrong was stripped of his seven Tour wins from 1999-2005 after the US Anti-Doping Agency exposed as lies his years of denials that he and his teammates doped.
Armstrong told Le Monde the US agency's findings ruined his life. And he claimed it didn't do anything beneficial for cycling.