Comparison
Hexarelin vs Ipamorelin
Both are gHRPs & ghrelin mimetics, so the meaningful differences are in kinetics, evidence and regulatory status.
On published evidence alone, Hexarelin is the better documented of the two (clinical trials). That is a statement about the state of the literature, not a recommendation.
| Hexarelin | Ipamorelin | |
|---|---|---|
| Class | GHRPs & ghrelin mimetics | GHRPs & ghrelin mimetics |
| Evidence | Clinical trials | Preliminary human |
| Human trials | ~14 | ~5 |
| Half-life | ~55 minutes | ~2 hours |
| Reported range | 100-200 mcg | 200-300 mcg |
| Frequency | 1-2x daily, short cycles only | 1-3x daily, on an empty stomach |
| Routes | Subcutaneous, Intramuscular | Subcutaneous |
| FDA approved | No | No |
| Research use only | Yes | Yes |
| Banned in sport | Yes | Yes |
| Studied for | Growth hormone elevation, Cardiac research, Short-cycle GH protocols | Growth hormone elevation, Recovery, Sleep quality, Body composition |
| Reported side effects | Elevated cortisol and prolactin, Water retention, Rapid tolerance, Lethargy | Head rush on injection, Transient hunger, Water retention, Lethargy |
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.
Ipamorelin
Ipamorelin is a pentapeptide agonist at the growth hormone secretagogue receptor, the same receptor targeted by endogenous ghrelin. Unlike the earlier GHRPs it produces a GH pulse without meaningful elevation of adrenocorticotropic hormone, cortisol or prolactin, which is the basis of its reputation as the cleanest compound in the class. It is short-acting and is typically dosed alongside a GHRH analog to exploit the synergy between the two receptor pathways.
Hexarelin vs Ipamorelin: common questions
What is the difference between Hexarelin and Ipamorelin?
Both are gHRPs & ghrelin mimetics. Hexarelin: The most potent GH-releasing hexapeptide of the group, with documented cardiac effects and the fastest receptor desensitisation. Ipamorelin: The most receptor-selective of the growth-hormone-releasing peptides, notable for leaving cortisol and prolactin essentially unchanged.
Which has stronger evidence, Hexarelin or Ipamorelin?
Hexarelin has the stronger evidence base (clinical trials, about 14 human studies) compared with Ipamorelin (preliminary human).
Are Hexarelin and Ipamorelin FDA approved?
Neither is FDA approved for any indication.
References
Regulatory and primary sources
- PubChem compound record (CID 6918297) ↗ · structure, identifiers, synonyms
- WADA Prohibited List ↗ · current year
- FDA: Unapproved drugs and "research use only" products ↗ · regulatory status of non-approved products
- CAS Registry Number 140703-51-1 ↗ · chemical identity
- PubChem compound record (CID 9831659) ↗ · structure, identifiers, synonyms
- CAS Registry Number 170851-70-4 ↗ · chemical identity
Published literature
- We are ageing.Biomed Res Int 2014.PubMed 25045704 · doi:10.1155/2014/808307
- Growth hormone-releasing peptides.Eur J Endocrinol 1997.PubMed 9186261 · doi:10.1530/eje.0.1360445
- Growth hormone in obesity.Int J Obes Relat Metab Disord 1999.PubMed 10193871 · doi:10.1038/sj.ijo.0800807
- The CD36-PPARγ Pathway in Metabolic Disorders.Int J Mol Sci 2018.PubMed 29883404 · doi:10.3390/ijms19051529
- The Safety and Efficacy of Growth Hormone Secretagogues.Sex Med Rev 2018.PubMed 28400207 · doi:10.1016/j.sxmr.2017.02.004
- Growth hormone-releasing peptides and their analogs.Front Neuroendocrinol 1998.PubMed 9465289 · doi:10.1006/frne.1997.0158
- Growth hormone-releasing peptides and the cardiovascular system.Ann Endocrinol (Paris) 2000.PubMed 10790589
- Implications of ghrelin and hexarelin in diabetes and diabetes-associated heart diseases.Endocrine 2015.PubMed 25645463 · doi:10.1007/s12020-015-0531-z
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- A new era of doping? Use of peptide and peptide-analog drugs in recreational and professional sport and bodybuilding: a critical review.J Sports Med Phys Fitness 2026.PubMed 41880199 · doi:10.23736/S0022-4707.26.17773-1
- Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers.Pharm Res 1999.PubMed 10496658 · doi:10.1023/a:1018955126402
- Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients.Int J Colorectal Dis 2014.PubMed 25331030 · doi:10.1007/s00384-014-2030-8
- Injectable Peptides in Sports Medicine: A Structured Narrative Review of Evidence, Safety, and Antidoping Implications.JBJS Rev 2026.PubMed 42160466 · doi:10.2106/JBJS.RVW.26.00027
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.