Paris  - Two new types of doping substances were possibly used at this year's Tour de France, according to the head of the French Anti-Doping Agency (AFLD).

Although there were no positive doping tests at the Tour, which was won for the second time in three years by Alberto Contador Sunday, Pierre Bordry told Tuesday's Le Monde newspaper that he wasn't convinced the race was clean.

Bordry believes that riders are still engaging in autologous blood transfusions, including third generation EPO (erythropoeitin).

The AFLD boss said he was "convinced" that two new drugs not yet available on the market have been used during the Tour.

"We found several strong medications, including a substance which produces insulin and normally is used for diabetes," added Bordry.

The drugs won't be available until 2011 but are already on the banned substances list of World Anti-Doping Agency (WADA).  (dpa)