GHRP.

Growth-hormone-releasing peptides, which act on the ghrelin receptor.

Growth-hormone-releasing peptides stimulate growth-hormone release by acting on the growth-hormone-secretagogue receptor, which is the receptor for the stomach hormone ghrelin. This is a different pathway from GHRH analogs, and the two are often discussed together precisely because activating both at once produces a larger release than either alone. The family includes GHRP-2, GHRP-6, hexarelin, and ipamorelin, and they differ in selectivity: some older members also raise cortisol and prolactin or strongly stimulate appetite through the same ghrelin receptor, while ipamorelin was designed to be more selective for growth-hormone release with less of that spillover. Like GHRH analogs, they act on the pituitary rather than supplying growth hormone directly, so the release remains pulsatile and remains subject to feedback. Two clarifications are worth making. Selectivity is a matter of degree rather than an on-off property, so a more selective compound is not necessarily free of the other effects. And raising growth hormone is a mechanism, not an outcome: whether a given increase produces any change in body composition, recovery, or anything else a person would notice is a separate question that requires separate evidence, and these compounds are generally not approved for human use.