Modified GRF 1-29 (also known as CJC-1295 without DAC) is a Growth Hormone Releasing Hormone (GHRH). It is categorized as a growth hormone secretagogue, a compound which stimulates increased secretion of growth hormone from the pituitary gland. Although similar to Sermorelin, Mod-GRF has four amino acid substitutions made to its chemical structure, hence the alternate name “tetrasubstituted” GRF 1-29. These changes effectively increase the stability of Mod GRF during storage, transportation, and administration while enhancing its affinity for the GHRH receptor.
Like the body’s natural GHRH, Mod-GRF works by binding to the growth hormone releasing hormone receptor (or GHRHr) in the anterior part of the pituitary gland. There, it works to amplify the pulsatile release of GH, consequently provoking increases in production of IGF-1 as well. Mod GRF works most effectively when administered at the same time as a release of GH in the body. This can be accomplished by timing administration with the body’s natural GH release or by administering it along with a GHRP to further amplify both peptides’ effects.