Effects of green tea on excretion of testosterone in urine

Sportspersons become more and more sophisticated in administration of steroids. They find new ways to hide their intake of banned medications. Some athletes take time to study scientists’ affirmations that can help them to hide that they dope. Nowadays a method has been found: sportspersons may mask administration of testosterone by drinking of green tea.
Testosterone is a hormone that is secreted in body naturally. Thus, it can be difficult for anti-doping agencies to determine that an athlete has taken testosterone. T: E ratio testing is usually used by anti-doping organizations. Such tests can demonstrate unusual ratio of testosterone to epitestosterone in urine. But it is not capable to manifest difference between testosterone that has been produced in body naturally and that introduced into body with the help of injections, creams, etc.
 Declan Naughton and his colleagues at Kingston University ( London) have found that green tea has such compounds 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 which can mask application of testosterone, are contained 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 hides intake of testosterone.
So, those sportspeople that take testosterone can lower quantities of testosterone that are excreted in urine by consumption of green or white tea. Green or white tea has capacity to block excretion of testosterone, enhancing circulating levels of this hormone.
The World Anti-Doping Agency was informed about the findings by the experts. If this process occurs, it is not worthy to test urine. Blood tests must be performed for detection of testosterone use.
Olivier Rabin, the WADA’s specialist, affirms that regular checks of blood steroids will be added. Everything will be done by anti-doping agencies in order to avoid fooling of urine tests.