Heavy consumption of the essential amino acid lysine (as indicated in the treatment of cold sores) has allegedly shown false positives in some and was cited by American shotputter C. J. Hunter as the reason for his positive test, though in 2004 he admitted to a federal grand jury that he had injected nandrolone.  A possible cause of incorrect urine test results is the presence of metabolites from other AAS, though modern urinalysis can usually determine the exact steroid used by analyzing the ratio of the two remaining nandrolone metabolites. As a result of the numerous overturned verdicts, the testing procedure was reviewed by UK Sport . On October 5, 2007, three-time Olympic gold medalist for track and field Marion Jones admitted to use of the drug, and was sentenced to six months in jail for lying to a federal grand jury in 2000. 
Still, you have to wonder how many top bodybuilders who have a lot of varicose veins got that way through an unfortunate combination of excess estrogen and heredity. Perhaps even certain styles of training are involved, although since the muscles assist the veins in returning blood to the heart, reducing pressure on veins, exercise would be an unlikely source of the problem. There’s not much a bodybuilder can do to prevent varicose veins, other than being aware of the effect of estrogen while doing everything you can to maintain normal testosterone. Some studies show that nutrients that strengthen the vein walls, such as vitamin C and bioflavonoids, offer some preventive effects, as do herbs that contain natural silicon, such as horsetail.