Positive tests for the urinary excretion of nandrolone metabolites (19-NA and 19-NE) are normally taken as evidence of illegal use of this anabolic-androgenic steroid drug. However, recent research has suggested that 19-NA and 19-NE can be produced naturally in the body, particularly by prolonged intense effort.

If this were true, it could mean that the current International Olympic Committee (IOC) threshold level for nandrolone metabolites is not high enough to rule out false positive findings.

That’s why a team of Belgian researchers recently carried out a study to investigate whether three different exercise methods were able to influence the urinary concentration of 19-NA and 19-NE in healthy young male subjects.

Fifteen amateur hockey players were randomly assigned to a running, cycling or bench-stepping group to undertake a 30-minute submaximal exercise test, with urine samples collected before the test and 60 minutes and 120 minutes afterwards.

Baseline urinary 19-NA and 19-NE concentrations were under the limit of detection of 0.05 ng/ml, except for one sample, which registered 0.13ng/ml. However, even this was well below the IOC threshold of 2ng/ml for men. No 19-NA or 19-NE could be detected in any of the subjects post-exercise.

The researchers conclude that exercise does not induce natural nandrolone secretion within the body, that the current IOC testing threshold is high enough to avoid false positives, and that positive testing is strongly suggestive of nandrolone use.

Int J Sports Med 2004; 25:528-523