"A much more likely theory has recently emerged from the results of a preliminary investigation at Aberdeen University. The findings are that dietary supplements themselves are harmless and produce no increased levels of nandrolone. Exercise alone, too, doesn't cause any problems. But a combination of both dietary supplements (none of which contain a banned substance) and exercise, can result in a positive nandrolone test. The reason for this is still unclear, but one theory is that there is a link between heavy training, the dehydration that goes with it, and their effects upon the components of high protein diets. Until more work is done, however, the 'nandrolone mystery' goes on..."

Nandrolone