Human Growth hormone (HGH), also known as somatotropin or somatropin, is a peptide hormone that stimulates growth, cell reproduction and regeneration in humans and other animals. It is a type of mitogen which is specific only to certain kinds of cells. Growth hormone is a 191-amino acid, single-chain polypeptide that is synthesized, stored, and secreted by somatotropic cells within the lateral wings of the anterior pituitary gland. Many factors influence the release of Human Growth Hormone, however, including nutrition and exercise.
Pesticides are also a disturbing gray area with only one of 23 high-risk pesticides tested for, the Inspector General’s office said. The presence of arsenic in poultry made food news in 2011 when a government study found inorganic arsenic, “ at higher levels in the livers of chickens treated” with arsenic-laced feed than in untreated chickens. This prompted Pfizer to stop marketing its arsenic feed, 3-Nitro, since arsenic is a carcinogen in its inorganic form. Worries are not over, though. The FDA still allows arsenic in poultry feed for weight gain and feed efficiency, to control parasites and to improve “pigmentation.” Other arsenic-laced feeds besides 3-Nitro remain on the market.
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.