at what levels cofein is doping for olympic athletes

I think you meant caffeine.

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[ http://www.rice.edu/~jenky/sports/caffeine.html ]

"The International Olympic Committee currently lists caffeine as a
restricted drug. Urinary levels up to a concentration of 12 mg/liter
are acceptable, representing casual use. Levels above this are viewed
as achieved through a deliberate attempt at doping by the athlete.
Approximately 1000mg of caffeine (about 8 cups of coffee) would be
required to exceed the current IOC limit, but it is very important to
note that people can metabolize caffeine at very different rates.
Differences in metabolism, medications, and certain diseases may
significantly alter the rate in which caffeine is cleared from the
body. Some athletes have come close to flunking the drug test after
ingesting only 350mg. It is wise to consider this before using
caffeine as an ergogenic aid."

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The following site also cites a level of 12 mg/liter as the allowable
amount according to IOC doping rules.

[ http://www.afpafitness.com/articles/Caffeine2.htm ]

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search strategy: caffeine doping athlete level olympic