GHRH analogs are built to resemble growth-hormone-releasing hormone, the hypothalamic signal that tells the pituitary to release a pulse. Sermorelin, tesamorelin, and the CJC-1295 component all bind the GHRH receptor — in effect repeating a message the body already sends, with differences in stability and how long the signal persists.
Ipamorelin reaches the same pituitary cells through a different door. It is a selective growth hormone secretagogue, acting at the ghrelin receptor rather than the GHRH receptor — a second, parallel input to the same system. Selective is the operative word: research interest centers on its comparatively narrow action on that pathway.
Because the two mechanisms are separate, they are sometimes paired. CJC-1295 / ipamorelin and tesamorelin / ipamorelin combine an analog with the secretagogue. Of these growth hormone peptides, Promise offers sermorelin, tesamorelin and the CJC-1295 / ipamorelin blend; the tesamorelin / ipamorelin blend is coming soon — add me to the list.
MK-677, or ibutamoren, also acts at the ghrelin receptor, but it is an orally active small molecule rather than a peptide. It is coming soon to Promise — add me to the list — and it is not FDA-approved.
