Growth hormone in sports which the anterior pituitary gland produces excess growth hormone. Human growth hormone occurs naturally in the human body. Use of exogenous human growth hormone (HGH), via injection, was originally for medical purposes until athletes began abusing HGH with the goal of increasing their abilities. Before recombinant human growth hormone (rHGH) was developed in 1981, HGH was only available from cadavers. The arrival of rHGH combined with other peptide hormone advancements has increased the availability of HGH on both the legitimate and black markets. The first description of the use of GM as a doping agent was Dan Duchaine’s “Underground Steroid
Drug delivery to the brain through the blood–brain barrier. Similar to the idea of pro-drugs, another way of masking the drugs chemical composition is by masking a peptide’s characteristics by combining with other molecular groups that are more likely to pass through the blood–brain barrier. An example of this is using a cholesteryl molecule instead of cholesterol that serves to conceal the water soluble characteristics of the drug. This type of masking as well as aiding in traversing the blood–brain barrier. It also can work to mask the drug peptide from peptide-degrading enzymes in the brain Also a "targetor" molecule could be attached to the