Floyd Landis lost his expensive and explosive doping case Thursday when arbitrators upheld the results of a test that showed the 2006 Tour de France champion used synthetic testosterone to fuel his spectacular comeback victory, The Associated Press has learned.

The decision means Landis, who repeatedly has denied using performance-enhancing drugs, must forfeit his Tour de France title and is subject to a two-year ban, retroactive to Jan. 30, 2007.

The ruling, handed down nearly four months after a bizarre and bitterly fought hearing, leaves the American with one final way to possibly salvage his title -- an appeal to the Court of Arbitration for Sport.

If Landis doesn't appeal, he'll be the first person in the 105-year history of the race to lose the title because of a doping offense.

According to documents obtained by AP, the vote was 2-1 to uphold the results, with lead arbitrator Patrice Brunet and Richard McLaren in the majority and Christopher Campbell dissenting.

"Today's ruling is a victory for all clean athletes and everyone who values fair and honest competition," U.S. Anti-Doping Agency CEO Travis Tygart said.

It's a devastating loss for Landis, who has steadfastly insisted that cheating went against everything he was all about and said he was merely a pawn in the anti-doping system's all-consuming effort to find cheaters and keep money flowing to its labs and agencies.

Landis didn't hide from the scrutiny -- invited it, in fact -- and now has been found guilty by the closest thing to a fair trial any accused athlete will get.

Landis, who has a month to file his appeal, is still weighing his legal options, according to a statement released by his legal team.

"This ruling is a blow to athletes and cyclists everywhere" Landis said. "For the Panel to find in favor of USADA when, with respect to so many issues, USADA did not manage to prove even the most basic parts of their case shows that this system is fundamentally flawed. I am innocent, and we proved I am innocent."

Despite the result, it's hard to see this as a total victory for the U.S. Anti-Doping Agency, which prosecuted the case. This was a costly affair for the agency, and it exposed flaws in the system.

In its 84-page decision, the majority found the initial screening test to measure Landis' testosterone levels -- the testosterone-to-epitestosterone test -- was not done according to World Anti-Doping Agency rules.

But the more precise and expensive carbon-isotope ration analysis (IRMS), performed after a positive T-E test is recorded, was accurate, the arbitrators said, meaning "an anti-doping rule violation is established."

"As has been held in several cases, even where the T-E ratio has been held to be unreliable ... the IRMS analysis may still be applied," the majority wrote. "It has also been held that the IRMS analysis may stand alone as the basis" of a positive test for steroids.

The decision comes more than a year after L test right, how can a person have any confidence that LNDD got the much more complicated IRMS test correct?"

It was confusion like this that led to the system receiving the harsh review Landis was hoping for during a nine-day hearing in Malibu, Calif., in May.

But Landis also took his share of abuse, and ultimately, USADA still improved to 35-0 in cases it has brought before arbitration panels since it was founded in 2000.

This was a nasty contest waged on both sides, with USADA attorneys going after Landis' character and taking liberties in evidence discovery that wouldn't be permitted in a regular court of law. And Landis accused USADA of using a win-at-all-costs strategy and prosecuting him only to get him to turn on seven-time winner Lance Armstrong, who has long fought doping allegations that have never been proven.

Addressing "problematic behavior on the part of both parties," the panel wrote it would not revisit the conduct of either side.

"They are just part of the litigation war games the parties counsel engaged in between themselves," the decision said.

More than the complex, turgid scientific evidence, the hearing will be remembered for the Greg LeMond brouhaha.

The hearing turned into a soap opera when the former Tour de France winner showed up and told of being sexually abused as a child, confiding that to Landis, then receiving a call from Landis' manager the night before his testimony threatening to disclose LeMond's secret to the world if LeMond showed up.

LeMond not only showed up, he also claimed Landis had admitted to him that he doped. That was the only aspect of the LeMond testimony the panel cared about.

"The panel concludes that the respondent's comment to Mr. LeMond did not amount to an admission of guilt or doping," the majority wrote.

This year's Tour began without the official defending champion, and the traditional "No. 1" jersey wasn't handed out when the race began in London. It only got worse as doping allegations and suspicions devastated the 2007 Tour. Three riders, including former overall leader Michael Rasmussen, and two teams were expelled during the three-week race.

At 31, Landis has vowed he hadn't given up on cycling -- he raced in small, nonsanctioned events in Colorado this summer -- even hoping to some day wear the yellow jersey again.