Essentially a synthetic version of ghrelin analogue, GHRP-6 (like GHRP-2) stimulates the release of an endogenous growth hormone (GH) within the somatotropes of the anterior pituitary in the animal and human body. Specifically, GHRP-6 will increase the number of somatotropes in a GH pulse by limiting the amount of somatostatin present, while standard GHRH increases the amplitude at which the pituitary cells pulse. Unlike ghrelin, GHRP-6 is not specifically used to increase appetite, but it may have secondary actions that impact hypothalamic neurons. These effects last for approximately an hour after the initial application, which mimics the natural application of GH, and consists of an eight hour circulation period. In studies GHRP-6 has shown biological actions similar to the naturally occurring hunger stimulating peptide ghrelin. Its main use is to promote food intake by stimulating hunger and aid in energy metabolism. It can be used in the treatment of GH deficiency as well as cachexia, eating disorders and obesity. GHRP-6 is a synthetic met-enkephalin (a naturally occurring opioid growth factor) analog. GHRP-6 contains D-amino acids that are entirely synthetic, lacks opioid activity, and shares no sequence relation with GHRH. It has also been shown that GHRP-6 can lead to re-stimulation of the natural production of HGH. Studies have shown that GHRP-6 increases the secretion of IGF-1 (InsulinLike Growth Factor 1) by the liver, which is speculated to be a required component in the anabolic mechanisms leading to the action of HGH. It also appears that GHRP-6 has positive implications for the central nervous system, as ghrelin is known to protect neurons. What may be the most interesting aspect of ghrelin (and therefore GHRP-6, it’s synthetic analog) is the huge variety of roles it plays in biological functions. It is involved in processes that include appetite regulation, cardiac functions, gastrointestinal functions, metabolism of carbohydrates, and even has some behavioral effects.