The Dianabol utilization intensifies the sebaceous glands because it has a strong androgen component which is converted in dihydrotestosteron; this side effect causes for some athletes acne on the face, on the neck, on the thorax or on the shoulders. In case of a hereditary predisposition, the Dianabol can accelerate the baldness because of the same thing: its transformation in dihydrotestosteron. The Dianabol action effect is significant for the endogen testosterone. The investigations demonstrated that a 20 mg daily dose can diminish the testosterone production level in the organism with 30-40% after only 10 days of use.
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.