Ghrelin vs Hexarelin

Must be acylated at Ser3 (by GOAT enzyme) for GHSR-1a binding. Receptor activation in the pituitary stimulates GH release; hypothalamic action via NPY/AgRP neurons increases appetite and reduces energy expenditure.

An endogenous 28-amino acid peptide hormone produced primarily by gastric oxyntic cells. Functions as both the primary hunger signal and a potent GH secretagogue. The natural ligand for the growth hormone secretagogue receptor (GHSR-1a).

Potent synthetic GHRP; strongest GH secretagogue in its class; also activates CD36 scavenger receptor for cardioprotective effects

The most potent synthetic GHRP, stimulating significant GH release. Also has direct cardioprotective properties independent of GH.