Many of these positive tests have occurred in Great Britain, where in 1999 alone there were 17. Several athletes, including U.S. Postal Service rider Benoit Joachim, have claimed these positive doping tests occurred inadvertently through the use of dietary supplements.
Experts continue to speculate over the recent increase in nandrolone positives.
Testing techniques allowing the period of nandrolone detection to be increased by several months have been in place since 1996 and this drug can be stored in the body for up to one year. Increasingly, it does seem possible that athletes are ingesting products called prohormones, intentionally or not, which are precursors to nandrolone and testosterone. Prohormones are easily purchased in the U.S., due to the passing of the Dietary Supplement Health and Education Act in 1994. Often found in supplements geared toward muscle building, recovery and maintaining hormone levels, these products may or may not be appropriately labeled. Many athletes have claimed inadvertent use of these products - some have been cleared, some have not.