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Growth hormone

Growth hormone secretagogues explained: GHRH analogues versus ghrelin mimetics

Peptides that raise growth hormone (GH) release fall into two families that act on different receptors. Mixing them up is the most common source of confusion in this area.

6 min read · Updated 2026-11-10

Key takeaways

  • ✓GHRH analogues act on the GHRH receptor; ghrelin mimetics act on the GHS receptor.
  • ✓The two pathways are distinct and can be studied separately or together.
  • ✓Short half-life and receptor desensitisation shape how each is used in experiments.

The GHRH receptor family

Growth-hormone-releasing hormone (GHRH) is a 44-residue hypothalamic peptide. Sermorelin is its 1-29 fragment, the shortest piece that keeps full activity. CJC-1295 and tesamorelin are modified analogues designed to last longer; tesamorelin is a full-length 44-residue analogue that is an approved medicine for a specific indication.

The ghrelin receptor family

Ghrelin is a gut hormone that activates the GHS receptor (GHS-R1a). GHRP-6, hexarelin and ipamorelin are synthetic ligands for it, developed before ghrelin itself was discovered. They differ in potency and selectivity: ipamorelin is reported as more selective for GH release, while GHRP-6 and hexarelin show broader hormonal effects in the published work.

Pulsatility and desensitisation

GH is naturally released in pulses. Cell and animal studies show that continuous receptor stimulation can blunt the response, and hexarelin is a well-documented example. This is why exposure pattern is a core design variable in secretagogue research.

Reading the downstream markers

Most studies track GH itself and IGF-1, the liver-derived mediator of GH signalling. Because IGF-1 integrates over hours, it behaves very differently from the minute-scale GH pulses.

Compounds mentioned

GH axisNot approved

CJC-1295

GHRH analogue

Evidence
2/5
GH axisNot approved

Ipamorelin

Selective ghrelin-receptor agonist

Evidence
2/5
GH axisApproved in the US for one indication

Tesamorelin

Stabilised full-length GHRH analogue

Evidence
5/5
GH axisNot approved

GHRP-6

First-generation ghrelin-receptor agonist

Evidence
2/5
GH axisFormerly approved (discontinued)

Sermorelin

Shortest fully active fragment of GHRH

Evidence
3/5
GH axisNot approved

Hexarelin

Potent synthetic ghrelin-receptor agonist

Evidence
2/5

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Cite this page

peptide.wiki. (2026). Growth hormone secretagogues explained: GHRH analogues versus ghrelin mimetics. peptide.wiki. https://www.peptide.wiki/guides/growth-hormone-secretagogues-explained
Free to cite and link. Last reviewed 2026-11-10.
For laboratory research only. Nothing on peptide.wiki is medical advice. The compounds described are not for human or veterinary use, and research-grade material is not a medicine.