This is largely because of the anti-steroid stance taken by the FDA and almost all other governing bodies in regards to anabolic steroid use – researchers don’t particularly want to go anywhere near prohormones and steroids to perform studies. They’re too much of a “taboo” substance. As such, we currently have no idea why prolactin-like side effects take place when using nandrolone and trenbolone; theories include a hypothesis that it somehow stimulates the pituitary gland to release prolactin, whereas others state that 19-nor steroids must interact in an unknown way with one’s biochemistry to produce these effects.
Nandrolone decanoate in the form of the Organon product, Deca-Durabolin, has been around for over 30 years. It has anabolic, androgenic, progestogenic and erythropoietic activity. The steroid maintains the anabolic activity of testosterone but the androgenic action is markedly diminished. The anabolic/androgenic quotient after 2 weeks of treatment has been shown to be 12 times that obtained with testosterone decanoate. Nandrolone decanoate has been shown to influence calcium metabolism positively and to increase bone mass in osteoporosis. Androgenic effects are relatively uncommon at the recommended therapeutic dosages.
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 AAS 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.