Peptide Monographs

GHRP-2 and GHRP-6 side by side

GHRP-2 and GHRP-6 are both indexed under Growth hormone secretagogues. Every cell below carries the record it came from, and an axis with no retrieved value reads Unknown rather than being filled by inference.

Summary

Both are synthetic growth hormone-releasing peptides acting at the ghrelin receptor, and the cited 1996 Journal of Endocrinology paper studies the two side by side on intracellular cyclic AMP. They differ in the endpoints the retrieved literature concentrates on.

[1, 2, 3, 4]

Side by side

Curated comparison axes for GHRP-2 and GHRP-6
AxisGHRP-2GHRP-6
Reported mechanismA synthetic growth hormone-releasing peptide described in the retrieved records as a ghrelin receptor agonist, with reported effects on growth hormone secretion and intracellular cyclic AMP.[10, 1]Acts through the growth hormone secretagogue receptor, the ghrelin receptor.[4]
Molecular formulaC45H55N9O6[5]C46H56N12O6[13]
Molecular weight818 g/mol[5]873 g/mol[13]
FDA application registerA query of the FDA Drugs@FDA application register on 2026-10-09 returned no application records for this compound name. This compound is not approved by the FDA for human use.[6]A query of the FDA Drugs@FDA application register on 2026-10-09 returned no application records for this compound name. This compound is not approved by the FDA for human use.[14]

Where the two literatures diverge

The GHRP-2 records include human endocrine studies, among them the cited 2005 Journal of Clinical Endocrinology and Metabolism paper reporting increased food intake in healthy men, and rodent inflammation work. The GHRP-6 records are dominated by receptor pharmacology, including the cited 2001 Molecular Endocrinology paper on Pit-1 expression through the growth hormone secretagogue receptor. Molecular weight differs by roughly 60 g/mol on the retrieved PubChem records. Neither returned an FDA application record.

[1, 2, 3, 4]

Where this page sits

Full pages: GHRP-2 and GHRP-6.

Shared class: Growth hormone secretagogues.

Other pairs in the same class

All side-by-side pages: index.

Sources

  1. The effects of GH-releasing peptide-6 (GHRP-6) and GHRP-2 on intracellular adenosine 3',5'-monophosphate (cAMP) levels and GH secretion in ovine and rat somatotrophs. The Journal of endocrinology (1996). pmid:8699133
  2. Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men. The Journal of clinical endocrinology and metabolism (2005). pmid:15699539
  3. Effects of GHRP-2 and hexarelin, two synthetic GH-releasing peptides, on GH, prolactin, ACTH and cortisol levels in man. Comparison with the effects of GHRH, TRH and hCRH. Peptides (1997). pmid:9285939
  4. Regulation of Pit-1 expression by ghrelin and GHRP-6 through the GH secretagogue receptor. Mol Endocrinol (2001). pmid:11518797
  5. PubChem Compound Summary for CID 6918245, Pralmorelin. PubChem, National Library of Medicine (2026). pubchem:6918245
  6. Drugs@FDA application register query for this compound, no application records returned. U.S. Food and Drug Administration, openFDA drugsfda endpoint (2026). fda:ghrp-2
  7. The effect of GH-releasing peptide-2 (GHRP-2 or KP 102) on GH secretion from primary cultured ovine pituitary cells can be abolished by a specific GH-releasing factor (GRF) receptor antagonist. The Journal of endocrinology (1994). pmid:8169551
  8. The combined administration of GH-releasing peptide-2 (GHRP-2), TRH and GnRH to men with prolonged critical illness evokes superior endocrine and metabolic effects compared to treatment with GHRP-2 alone. Clinical endocrinology (2002). pmid:12030918
  9. Anti-inflammatory effect of the ghrelin agonist growth hormone-releasing peptide-2 (GHRP-2) in arthritic rats. American journal of physiology. Endocrinology and metabolism (2005). pmid:15507538
  10. Ghrelin receptor agonist GHRP-2 prevents arthritis-induced increase in E3 ubiquitin-ligating enzymes MuRF1 and MAFbx gene expression in skeletal muscle. American journal of physiology. Endocrinology and metabolism (2005). pmid:16030067
  11. Identification of the growth-hormone-releasing peptide-2 (GHRP-2) in a nutritional supplement. Drug testing and analysis (2010). pmid:20878896
  12. Determination of growth hormone secretagogue pralmorelin (GHRP-2) and its metabolite in human urine by liquid chromatography/electrospray ionization tandem mass spectrometry. Rapid communications in mass spectrometry : RCM (2010). pmid:20552695
  13. PubChem Compound Summary for CID 4345065, Ghrp-6. PubChem, National Library of Medicine (2026). pubchem:4345065
  14. Drugs@FDA application register query for this compound, no application records returned. U.S. Food and Drug Administration, openFDA drugsfda endpoint (2026). fda:ghrp-6
  15. Massive growth hormone (GH) discharge in obese subjects after the combined administration of GH-releasing hormone and GHRP-6: evidence for a marked somatotroph secretory capability in obesity. J Clin Endocrinol Metab (1993). pmid:8473389
  16. Blocked growth hormone-releasing peptide (GHRP-6)-induced GH secretion and absence of the synergic action of GHRP-6 plus GH-releasing hormone in patients with hypothalamopituitary disconnection: evidence that GHRP-6 main action is exerted at the hypothalamic level. J Clin Endocrinol Metab (1995). pmid:7883854
  17. Comparison of the gastroprokinetic effects of ghrelin, GHRP-6 and motilin in rats in vivo and in vitro. Eur J Pharmacol (2005). pmid:15890336
  18. The effects of ghrelin antagonists [D-Lys(3) ]-GHRP-6 or JMV2959 on ethanol, water, and food intake in C57BL/6J mice. Alcohol Clin Exp Res (2014). pmid:25257292

On each stated value was matched to the record cited for it. That is record matching, not an appraisal of the research. Compiled and checked by: Peptide Monographs editorial desk. No qualified clinical reviewer.

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