1)GHRP - 2
GH Releasing Peptide 2(GHRP2) substantially stimulates the pituitary gland's increased natural production of the body's own endogenous human GH . This therapy consists of daily periodic sub-lingual dosing. GH releasing peptide 2, GHRP2 has shown on it's own to robustly increase IGF-1 levels, and even greater results occurred when used with GH Releasing Hormone (GHRH) to which also stimulates the pituitary gland to produce increased natural secretion of human GH. This also boosts the hypothalamus function as well.

2)GHRP - 6
GHRPs are not simply surrogates of GHRH, instead GHRP-6 is an artificial activator of a separate newly discovered receptor called GH Secretagogue Receptor (GHS-R). Soon Ghrelin was discovered, the endogenous ligand that binds to the GHS-R. Both Ghrelin and all the synthetic compounds such as GHRP-6 were termed "GH Secretagogues" (GHSs). One side effect of GHRP-6 is a significant increase in appetite due to stimulating the release of Ghrelin, a peptide that is released naturally in the lining of the stomach that increases hunger and gastric emptying. Also, GHRP-6 causes stimulation of the anterior pituitary gland which causes an increase in GH release. The increased amounts of GH can cause the liver to secrete the hormone IGF-1, which improves the animal body's ability to burn fat and build muscle. Since GHRP-6 acts directly on the feedback loop which signals the inhibition of GH release, GHRP-6 can re-stimulate the production of GH.