Anti-doping agencies are warned that green tea may mask testosterone use

Sportspersons become more and more sophisticated in usage of steroids. They find new methods to mask their administration of forbidden products. Some sportspersons spend time studying scientists’ statements which may help them to hide that they dope. Nowadays a way has been found: athletes can mask intake of testosterone by drinking of green tea.
Testosterone is a hormone that is produced in body naturally. Thus, it may be difficult for anti-doping agencies to determine that an athlete has used testosterone. T: E ratio testing is ordinarily used by anti-doping organizations. Such tests can manifest uncommon ratio of testosterone to epitestosterone in urine. But it is not capable to display difference between testosterone which has been produced in body naturally and that introduced into body with the help of injections, gels, etc.
 Declan Naughton and his colleagues at Kingston University ( London) have determined that green tea has such substances that are called “catechins”. They have capacity to inhibit the enzyme UGT2B17. This enzyme induces attaching glucuronic acid to testosterone. In case UGT2B17 is inhibited, less testosterone glucoronide is excreted in urine.  
Catechins, the substances that are able to mask usage of testosterone, are in green and white tea. Black tea doesn’t contain such compounds.
Naughton and his colleagues have conducted certain experiments. They claim that a cup of strong green tea mask administration of testosterone.
Thus, those athletes that administer testosterone can reduce amounts of testosterone excreting in urine by consumption of green or white tea. Green or white tea has capacity to block excretion of testosterone, increasing circulating levels of this hormone.
The World Anti-Doping Agency was informed about the discovering by the scientists. If this process occurs, it means that it is not worthy to test urine. Blood tests must be performed in order to detect testosterone use.
Olivier Rabin, the WADA’s scientist, affirms that regular checks of blood steroids will be added. Everything will be done by anti-doping officials in order to avoid fooling of urine tests.