GHRP-6 is an effective stimulator of natural Growth Hormone Release from the anterior pituitary. GHRP-6 is also a ghrelin/growth hormone receptor agonist and one of a handful of ghrelin analogues developed in the last several decades. It has been found to have positive effects on heart muscle cells, memory formation, scar formation, sex motivation, and the neurons involved in Parkinson’s disease. GHRP-6 is orally and sublingually active and moderately to highly selective.
GHRP-2 (a.k.a. pralmorelin) is a synthetic growth hormone secretagogue known to bind to the ghrelin/growth hormone secretagogue receptor. It was the first of the growth hormone secretagogues to be introduced and is currently marketed as a test peptide for the assessment of growth hormone deficiency and secondary adrenal failure. GHRP-2 has been investigated in stage II clinical trials for the assessment of short stature and is under active research for its effects on appetite, muscle growth, the immune system, and sleep cycles. GHRP-2 is orally and sublingually active, so it does not have to be injected to have its effects.