Whey protein is the most studied supplement after Creatine. It has been proven that protein helps build muscle, with the ideal ingestion time being immediately post-workout, or in your “anabolic window.” The only protein that is able to be digested within 45 minutes is whey due to its purity and chemical properties. Whey usually comes in a few forms: Hydrolysate, Isolate and Concentrate. Isolate is more filtered, and is more quickly absorbed by the body than Concentrate. However, it is important to keep a balance of both, since your muscles have a constant demand for protein.
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.