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Comparison

GHRP-6 vs Hexarelin

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

GHRP-6 Hexarelin
Class GHRPs & ghrelin mimetics GHRPs & ghrelin mimetics
Evidence Clinical trials Clinical trials
Human trials ~10 ~14
Half-life ~15-30 minutes ~55 minutes
Reported range 100-300 mcg 100-200 mcg
Frequency 2-3x daily 1-2x daily, short cycles only
Routes Subcutaneous, Intramuscular Subcutaneous, Intramuscular
FDA approved No No
Research use only Yes Yes
Banned in sport Yes Yes
Studied for Appetite stimulation, Growth hormone elevation, Recovery research Growth hormone elevation, Cardiac research, Short-cycle GH protocols
Reported side effects Pronounced hunger, Elevated cortisol and prolactin, Water retention, Head rush Elevated cortisol and prolactin, Water retention, Rapid tolerance, Lethargy

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.

Hexarelin

Hexarelin is a methylated analog of GHRP-6 with higher potency at the growth hormone secretagogue receptor. It additionally binds CD36, a scavenger receptor expressed in cardiac tissue, which underlies the cardioprotective effects reported in ischaemia models and distinguishes it pharmacologically from the rest of the class. Its clinical limitation is rapid tachyphylaxis: GH response attenuates substantially within two to three weeks of continuous use.

GHRP-6 vs Hexarelin: common questions

What is the difference between GHRP-6 and Hexarelin?

Both are gHRPs & ghrelin mimetics. GHRP-6: The original growth-hormone-releasing hexapeptide, now used as much for its pronounced appetite stimulation as for GH release. Hexarelin: The most potent GH-releasing hexapeptide of the group, with documented cardiac effects and the fastest receptor desensitisation.

Which has stronger evidence, GHRP-6 or Hexarelin?

They sit at the same evidence level: clinical trials. GHRP-6 has about 10 human studies and Hexarelin about 14.

Are GHRP-6 and Hexarelin FDA approved?

Neither is FDA approved for any indication.

References

Regulatory and primary sources

  1. PubChem compound record (CID 4345065) ↗ · 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 87616-84-0 ↗ · chemical identity
  5. PubChem compound record (CID 6918297) ↗ · structure, identifiers, synonyms
  6. CAS Registry Number 140703-51-1 ↗ · 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. 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
  3. Gasco V, Corneli G, Rovere S, et al.. Diagnosis of adult GH deficiency.Pituitary 2008.PubMed 18404387 · doi:10.1007/s11102-008-0110-x
  4. 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
  5. 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
  6. 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
  7. 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
  8. Camanni F, Ghigo E, Arvat E. Growth hormone-releasing peptides and their analogs.Front Neuroendocrinol 1998.PubMed 9465289 · doi:10.1006/frne.1997.0158
  9. Kolovou GD, Kolovou V, Mavrogeni S. We are ageing.Biomed Res Int 2014.PubMed 25045704 · doi:10.1155/2014/808307
  10. Maréchal L, Laviolette M, Rodrigue-Way A, et al.. The CD36-PPARγ Pathway in Metabolic Disorders.Int J Mol Sci 2018.PubMed 29883404 · doi:10.3390/ijms19051529
  11. Muccioli G, Broglio F, Valetto MR, et al.. Growth hormone-releasing peptides and the cardiovascular system.Ann Endocrinol (Paris) 2000.PubMed 10790589
  12. Mosa RM, Zhang Z, Shao R, et al.. Implications of ghrelin and hexarelin in diabetes and diabetes-associated heart diseases.Endocrine 2015.PubMed 25645463 · doi:10.1007/s12020-015-0531-z

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.