Source comparison
Mechanism Comparison: GHRP-2 vs Endogenous Ghrelin
GHRP-2 and ghrelin both activate GHS-R1a, but GHRP-2 has approximately 100-fold higher receptor affinity and is resistant to degradation by ghrelin O-acyltransferase (GOAT). The enzyme required for ghrelin's biological activity. Endogenous ghrelin is acylated
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- GHRP-2 and ghrelin both activate GHS-R1a, but GHRP-2 has approximately 100-fold higher receptor affinity and is resistant to degradation by ghrelin O-acyltransferase (GOAT). The enzyme required for ghrelin's biological activity. Endogenous ghrelin is acylated at Ser3 with an octanoyl group, which is essential for receptor binding; GHRP-2's synthetic structure bypasses this requirement entirely. Additionally, ghrelin stimulates appetite through hypothalamic NPY/AgRP neuron activation. GHRP-2 does not produce the same orexigenic effect at standard research doses, though doses above 2 µg/kg may trigger mild hunger signalling in some subjects.
- In our experience working with institutions comparing secretagogues, GHRP-2 produces more consistent GH responses across subjects than ghrelin mimetics like ipamorelin or hexarelin, likely due to its simpler receptor interaction and lack of desensitisation after repeated administration. Hexarelin, for example, induces prolactin and cortisol elevation alongside GH. GHRP-2 demonstrates minimal cross-reactivity with prolactin or ACTH pathways at therapeutic doses.