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. 
Norplant was used internationally beginning in 1983 and was marketed in the United States and the United Kingdom in 1993. There were many complications associated with Norplant insertion and removal in the United States and it was taken off the market in 2002. Although Jadelle was approved by the FDA, it has never been marketed in the United States, but it is widely used in Africa and Asia.  Implanon was first used in Indonesia in 1998 and approved for use in the United States in 2006. Nexplanon was developed to eliminate the problem of non-insertion and localization of Implanon by changing the inserter device and making the rod radiopaque.  Nexplanon has replaced Implanon in the UK because of cases of incorrect insertion. As of January 2012, Implanon is no longer being marketed in the US, and Nexplanon is the only available single-rod implant.
Binding to the androgen receptor of rat seminal vesicle was studied in vitro using cell-free extract or minced tissue. Relative binding affinities of 5 alpha-dihydrotestosterone (DHT), 5 alpha-dihydro-19-nortestosterone (DHN), nortestosterone and testosterone were estimated from their competition with [3H]-DHT for the binding sites. In contrast with the conflicting results obtained with cell-free systems incubated at 0-15 degrees C, studies performed with vesicular mince at 37 degrees C proved to be useful to demonstrate characteristic differences in binding affinity and to gain information about binding both to cytosol and nuclear receptors. Competition data were graphically analyzed, and after correction for steroid metabolism the following relative competition indices were obtained: DHT = ; nortestosterone = -; testosterone = -; DHN = . However, binding to cytosolic and nuclear receptors did not differ significantly. It is concluded that testosterone and 19-nortestosterone (which are equally good substrates for 5 alpha-reductase) are converted in the seminal vesicles to metabolites, of which DHT exhibits an affinity to the androgen receptor nearly one order of magnitude higher than that of DHN. On the other hand, in skeletal muscles that are practically devoid of 5 alpha-reductase activity, the 3-fold higher affinity of nortestosterone to the receptor, expectedly, results in a myotropic activity that is superior to that of testosterone.