Glossary
Growth Hormone Secretagogue
A GH secretagogue makes the pituitary release its own growth hormone. The three mechanistic groups and how they differ from supplying HGH from outside.
Growth hormone secretagogues are compounds that cause the pituitary to release the growth hormone it produces itself, instead of providing the hormone externally. The term describes a mechanism rather than a structure and covers three groups.
Three mechanistic groups
- Agonists of the GHRH receptor — GHRH analogs like sermorelin, Mod GRF 1-29 and tesamorelin, working through GHRHR
- Agonists of the ghrelin receptor — the GHRPs, working through GHS-R1a
- Small-molecule GHS-R1a agonists — non-peptide, orally active compounds such as ibutamoren (MK-677)
Contrast with exogenous growth hormone
Recombinant human growth hormone is a prescription-only biologic that delivers the hormone itself and bypasses the natural pulsatile pattern. Secretagogues work one step earlier, on the somatotrophs, so the release they produce keeps its pulsatile character and is still limited by negative feedback from somatostatin and IGF-1. This built-in feedback ceiling is what defines the class mechanistically, and it is why studies frequently combine a GHRH analog with a GHRP so that both receptors are engaged.
Related terms
Browse growth hormone and performance peptides, or read the muscle growth research overview.