The 23-year-old Da Ros appealed to have his ban reduced to a maximum of two years, but cannot race again until March 2013.

CAS confirmed that Da Ros used, possessed and supplied banned drugs, but said it was not established that he administered--or attempted to administer--them to another rider.

The ruling said cyclist Davide Lucato told Italy's anti-doping prosecutor that he bought banned drugs for Da Ros.

A longtime friend, Albino Corazzin, gave evidence that Da Ros offered to provide him with HGH and Andriol testosterone, an oral anabolic steroid.

Da Ros told the Italian investigation he first got doping products from Lucato in 2008, and provided HGH to Corazzin later that year. He denied providing Andriol for Corazzin.

Da Ros was arrested in March 2009 during an investigation into a drug-trafficking ring.

He had been training with Italy's national track racing squad, and was suspended by his team Liquigas.

Last November, Italy's Olympic committee banned Lucato for eight years and Corazzin for two years.