Effect of ethanol on the ratio between testosterone and epitestosterone in urine

The testosterone/epitestosterone weight ratio in urine is used to detect cases of doping when an athlete has treated himself with exogenous testosterone. When this ratio exceeds 6, it is considered evidence of testosterone doping. We show here that intake of ethanol can affect this ratio. Ingestion of 110-160 g of ethanol, about 2 g per kilogram body weight, increased the ratio between testosterone and epitestosterone in urine from 1.14 +/- 0.07 to 1.52 +/- 0.09 in four healthy male volunteers. The increase ranged from 30% to 90% in the different subjects studied (mean 41%). In cases where doping with testosterone is suspected, the possibility should be considered that at least part of an observed increased testosterone/epitestosterone ratio in urine is ascribable to previous ingestion of ethanol.