Lance Armstrong announced Thursday he's giving up his battle against the US Anti-Doping Agency and will no longer defend their accusations that he's guilty of illegal doping during his decorated career. The USADA announced, thereafter, that it will strip Armstrong, 40, of his seven Tour de France titles and ban him from cycling for linfe.

Armstrong said in a statement on his website:

    "There comes a point in every man's life when he has to say, 'Enough is enough.' For me, that time is now. I have been dealing with claims that I cheated and had an unfair advantage in winning my seven Tours since 1999. Over the past three years, I have been subjected to a two-year federal criminal investigation followed by [an] unconstitutional witch hunt. The toll this has taken on my family, and my work for our foundation and on me leads me to where I am today – finished with this nonsense."

USADA CEO Travis T. Tygart said: "This is a heartbreaking example of how the win-at-all costs culture of sport, if left unchecked, will overtake fair, safe and honest competition, but for clean athletes, it is a reassuring reminder that there is hope for future generations to compete on a level playing field without the use of performance-enhancing drugs."

Armstrong has twice retired from the sport -- first in 2005 and again in 2011. He battled testicular cancer in 1996 at age 25 and beat if with surgery and new chemotherapy treatments.

Armstrong wrote on his LiveStrong site:

    "Today I turn the page. I will no longer address this issue, regardless of the circumstances," Armstrong said. "I will commit myself to the work I began before ever winning a single Tour de France title: serving people and families affected by cancer, especially those in underserved communities."