Pub. L. 101–647, title XIX , § 1903, Nov. 29, 1990 , 104 Stat. 4853 , as amended by Pub. L. 108–358 , § 2(c), Oct. 22, 2004 , 118 Stat. 1663 , provided that: “(a) Drugs for Treatment of Rare Diseases.— If the Attorney General finds that a drug listed in paragraph (41) of section 102 of the Controlled Substances Act (as added by section 2  of this Act) is— “(1) approved by the Food and Drug Administration as an accepted treatment for a rare disease or condition, as defined in section 526 of the Federal Food, Drug , and Cosmetic Act ( 21 . 360bb ); and “(2) does not have a significant potential for abuse, the Attorney General may exempt such drug from any production regulations otherwise issued under the Controlled Substances Act as may be necessary to ensure adequate supplies of such drug for medical purposes. “(b) Date of Issuance of Regulations.— The Attorney General shall issue regulations implementing this section not later than 45 days after the date of enactment of this Act [ Nov. 29, 1990 ], except that the regulations required under section 3(a) [former 1903(a)] shall be issued not later than 180 days after the date of enactment of this Act.”
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.