Ipamorelin also known as IPAM, MNC-26-0161 or ipamorelin acetate is a 5 amino acid polypeptide that is manufactured synthetically, the peptide has similar properties to that of GHRP-6 with an amino acid sequence Aib-His-D-2-Nal-D-Phe-Lys-NH2 and a molecular mass of 0.711-kilo Daltons. The peptide is classified as growth hormone releasing peptide because of its ability to stimulate the secretion of GH. Similar to other counterparts in the category GHRP-6 and GHRP-2, ipamorelin promotes the production, secretion, and effectiveness of GH. The secretion of GH occurs on the anterior lobe of the pituitary gland, the peptide was discovered in the early 90s and has since attracted various interests in the scientific research world. The activity of Ipamorelin on the somatoropes is still under research, however studies have shown that the hormone has a positive feedback mechanism on the release of GH. Ipamorelin is the 3rd generation of the growth hormone releasing peptides after GHRP, GHRP-2, and GHRP-6 , recent studies reveals that its mechanism of action and properties are similar to that of GHRP-2 , however it does not have lipogenic properties or induce hunger.
Ipamorelin works in synergy with Sermorelin and GRF 1-29 , these hormones work by inhibiting somatostatin pulses an as indicated earlier somatostatin is an antagonist of GH. The mechanism of action of ipamorelin is through the increase in the number and volume of GH produced by the somatorope cells. GHRP-6 has similar properties with ipamorelin in that they release GH at the same intensity and amount. GHRP-2 and GHRP-6 are known to promote the increase in prolactin and cortisol levels in the plasma , on the other hand, hexarelin has similar characteristics with ipamorelin because they are the most stable form of Ghrelin with an extended half-life. In addition, ipamorelin does not induce any significant effect on the insulin growth factor 1 levels , moreover it has the ability to increase the levels of acetylcholine in the system . Acetylcholine forms an integral part in cell-to-cell communication and it binds to specific cell receptors, which in turn promotes the binding of GH to ligand.
Recent research reveals that ipamorelin mechanism of action is mainly through the activation of specific G-protein secretagogues, which increases gastric motility and emptying. The main target of the GH receptors are located on the anterior lobe of pituitary gland , however the hormone does not cause any major effect on plasma levels of PRL,FSH, LH and TSH. The GHRH receptor called GRLN activates minute compounds on the pituitary gland, which in turn induces the release of GH. Ipamorelin acts on the same receptor to induce the release of GH, the hormone is vital in cell division, cell proliferation , differentiation, development, and maturity. Cell division and maturity is essential for growth and development , moreover the potency of ipamorelin is similar to that of GHRP-2 , and however with an extended half-life the hormone is more active and has a higher efficacy. D-Lys3-GHRP-6 is the only known antagonist to the peptide as it acts by denaturing the receptor sites of the hormone therefore the hormone will miss to bind on the ligand. Few or no binding sites results in low production of the GH.