From Wikidepidia:
Use as performance-enhancing drug
As a β2 sympathomimetic, clenbuterol has also been used as a performance-enhancing drug. Cyclist Alberto Contador of Spain was banned for two years from professional cycling after testing positive for the drug at the 2010 Tour de France.[4] He was later stripped of the 2010 title of the Tour de France and the 2011 title of the Giro d'Italia.[5] However, CAS found that Contador did not take clenbuterol as a performance-enhancing drug, but probably tested positive due to a contaminated food supplement.[6]
American swimmer Jessica Hardy tested positive at the US trials in 2008. She served a one-year suspension, having claimed she unknowingly took the drug in a contaminated food supplement. Former New York Mets clubhouse employee Kirk Radomski admitted in his plea deal to distributing clenbuterol to dozens of current and former Major League Baseball players and associates.[7]
After finishing fourth in the K-2 1000 m event at the 2008 Summer Olympics in Beijing, Polish sprint canoer Adam Seroczyński was disqualified for taking this drug; and Chinese cyclist Li Fuyu tested positive for it at the Dwars door Vlaanderen race in Belgium on March 24, 2010.[8]
In 2006, San Francisco Giants pitcher Guillermo Mota, while a member of the New York Mets, received a 50-game suspension after testing positive for clenbuterol.[9] In 2012, MLB announced they were again suspending Mota for 100 games due a positive test for clenbuterol.[10]
In 2010, St. Louis Cardinals minor-league shortstop Lainer Bueno received a 50-game suspension for the 2011 season as a result of testing positive for clenbuterol.[11]
In 2011, players of the Mexico national football team were found with clenbuterol in their bloodstreams, but were acquitted by WADA after they claimed the clenbuterol came from contaminated food. FIFA has also claimed 109 players from the Under-17 World Cup in Mexico tested positive for this drug, because Mexican meat is contaminated.[12]
In 2012, Canadian weightlifter Nick Roberts received a two-year sanction after a urine sample tested positive for clenbuterol.[13]
I guess it's some people that use it for performance
