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Comparison

GHRP-2 vs GHRP-6

Both are gHRPs & ghrelin mimetics, so the meaningful differences are in kinetics, evidence and regulatory status.

GHRP-2 GHRP-6
Class GHRPs & ghrelin mimetics GHRPs & ghrelin mimetics
Evidence Clinical trials Clinical trials
Human trials ~12 ~10
Half-life ~30 minutes ~15-30 minutes
Reported range 100-300 mcg 100-300 mcg
Frequency 2-3x daily 2-3x daily
Routes Subcutaneous, Intramuscular, Intranasal Subcutaneous, Intramuscular
FDA approved No No
Research use only Yes Yes
Banned in sport Yes Yes
Studied for GH secretory testing, Growth hormone elevation, Appetite stimulation Appetite stimulation, Growth hormone elevation, Recovery research
Reported side effects Increased appetite, Elevated cortisol and prolactin, Water retention, Tiredness Pronounced hunger, Elevated cortisol and prolactin, Water retention, Head rush

GHRP-2

GHRP-2 is a synthetic hexapeptide agonist at the growth hormone secretagogue receptor. It produces a larger GH pulse than ipamorelin at comparable doses, but with measurable increases in cortisol and prolactin, which is the trade-off that defines its position in the class. It is approved in Japan under the name pralmorelin as a diagnostic test of pituitary GH reserve.

GHRP-6

GHRP-6 is a hexapeptide agonist at the growth hormone secretagogue receptor and was the first of the class to be characterised. Its defining clinical feature is a strong, rapid increase in hunger through central ghrelin-receptor activation, considerably greater than ipamorelin or GHRP-2. That appetite effect is the reason it is selected in bulking contexts and avoided in fat-loss contexts.

GHRP-2 vs GHRP-6: common questions

What is the difference between GHRP-2 and GHRP-6?

Both are gHRPs & ghrelin mimetics. GHRP-2: A potent ghrelin-receptor agonist approved in Japan as a diagnostic agent, with a stronger GH pulse than ipamorelin and more hormonal spillover. GHRP-6: The original growth-hormone-releasing hexapeptide, now used as much for its pronounced appetite stimulation as for GH release.

Which has stronger evidence, GHRP-2 or GHRP-6?

They sit at the same evidence level: clinical trials. GHRP-2 has about 12 human studies and GHRP-6 about 10.

Are GHRP-2 and GHRP-6 FDA approved?

Neither is FDA approved for any indication.

References

Regulatory and primary sources

  1. PubChem compound record (CID 6918245) ↗ · structure, identifiers, synonyms
  2. WADA Prohibited List ↗ · current year
  3. FDA: Unapproved drugs and "research use only" products ↗ · regulatory status of non-approved products
  4. CAS Registry Number 158861-67-7 ↗ · chemical identity
  5. PubChem compound record (CID 4345065) ↗ · structure, identifiers, synonyms
  6. CAS Registry Number 87616-84-0 ↗ · chemical identity

Published literature

  1. Ghigo E, Arvat E, Muccioli G, et al.. Growth hormone-releasing peptides.Eur J Endocrinol 1997.PubMed 9186261 · doi:10.1530/eje.0.1360445
  2. Fukuda I, Hizuka N, Muraoka T, et al.. Adult growth hormone deficiency: current concepts.Neurol Med Chir (Tokyo) 2014.PubMed 25070016 · doi:10.2176/nmc.ra.2014-0088
  3. Pralmorelin: GHRP 2, GPA 748, growth hormone-releasing peptide 2, KP-102 D, KP-102 LN, KP-102D, KP-102LN.Drugs R D 2004.PubMed 15230633 · doi:10.2165/00126839-200405040-00011
  4. Camanni F, Ghigo E, Arvat E. Growth hormone-releasing peptides and their analogs.Front Neuroendocrinol 1998.PubMed 9465289 · doi:10.1006/frne.1997.0158
  5. Vodnik M, Štrukelj B, Lunder M. Ghrelin Receptor Ligands Reaching Clinical Trials: From Peptides to Peptidomimetics; from Agonists to Antagonists.Horm Metab Res 2016.PubMed 26551992 · doi:10.1055/s-0035-1564149
  6. Muccioli G, Broglio F, Valetto MR, et al.. Growth hormone-releasing peptides and the cardiovascular system.Ann Endocrinol (Paris) 2000.PubMed 10790589
  7. Celichowska M, Miedziaszczyk M, Lacka K. Pharmacotherapy in Cachexia: A Review of Endocrine Abnormalities and Steroid Pharmacotherapy.J Pain Palliat Care Pharmacother 2022.PubMed 35758863 · doi:10.1080/15360288.2022.2063469
  8. Argente J, García-Segura LM, Pozo J, et al.. Growth hormone-releasing peptides: clinical and basic aspects.Horm Res 1996.PubMed 8950613 · doi:10.1159/000185015
  9. Scacchi M, Pincelli AI, Cavagnini F. Growth hormone in obesity.Int J Obes Relat Metab Disord 1999.PubMed 10193871 · doi:10.1038/sj.ijo.0800807
  10. Gasco V, Corneli G, Rovere S, et al.. Diagnosis of adult GH deficiency.Pituitary 2008.PubMed 18404387 · doi:10.1007/s11102-008-0110-x
  11. Sigalos JT, Pastuszak AW. The Safety and Efficacy of Growth Hormone Secretagogues.Sex Med Rev 2018.PubMed 28400207 · doi:10.1016/j.sxmr.2017.02.004
  12. Pombo M, Leal-Cerro A, Barreiro J, et al.. Growth hormone releasing hexapeptide-6 (GHRP-6) test in the diagnosis of GH-deficiency.J Pediatr Endocrinol Metab 1996.PubMed 8887178
  13. Anderson LL, Jeftinija S, Scanes CG, et al.. Physiology of ghrelin and related peptides.Domest Anim Endocrinol 2005.PubMed 15927771 · doi:10.1016/j.domaniend.2005.02.033
  14. Smith RG, Leonard R, Bailey AR, et al.. Growth hormone secretagogue receptor family members and ligands.Endocrine 2001.PubMed 11322507 · doi:10.1385/ENDO:14:1:009

Literature retrieved from PubMed on October 16, 2026, favouring human studies and reviews. Numbered markers in the text show which paper supports which statement; uncited entries are background reading.

Read this first This page compares published reference data. It is not medical advice and not a recommendation to use either compound. Several compounds documented on this site are not approved for human use.