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Ipamorelin vs GHRP-6

How Ipamorelin and GHRP-6 differ on mechanism, dosing, and the strength of the evidence behind each.

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Compiled from published research · Continuously updated

How this is graded

Every compound below carries a REGEN research grade, from S (regulatory approval behind the use it is bought for) down to F (no clinical evidence). Ordering follows that grade rather than search volume, so the compound at the top is the one with the most evidence, not the one most often sold. Doses are those reported in published protocols and are not recommendations.

Ipamorelin

Cgrade200–300 mcg

Ipamorelin is a selective growth hormone secretagogue that mimics ghrelin to trigger a clean pulse of growth hormone from the pituitary, without the cortisol, prolactin, or hunger spikes seen with older secretagogues like GHRP-6. Its selectivity makes it one of the most popular and well-tolerated GH peptides. It is typically paired with a GHRH like CJC-1295 to produce a larger, more physiological GH release. Common goals are recovery, sleep quality, and gradual improvements in body composition. Track IGF-1 to confirm response.

GHRP-6

Dgrade100–300 mcg

GHRP-6 is one of the original growth hormone releasing peptides, a ghrelin mimetic that prompts the pituitary to release growth hormone. Its defining feature is pronounced hunger via ghrelin signaling, which can be useful in a bulking context but unwanted otherwise. It is typically paired with a GHRH analog for a larger, more physiological GH release. Higher doses can transiently raise cortisol and prolactin. Track IGF-1 on cycle.

Evidence compared

 IpamorelinGHRP-6
Research gradeCgradeDgrade
Reported dose200–300 mcg100–300 mcg
Frequency1-3x daily1-3x daily
Half-life~2 hours~15-30 min
Routessubcutaneoussubcutaneous
Tracked outcomesBody Composition, Muscle Growth, Sleep QualityBody Composition, Muscle Growth, Sleep Quality
Contraindicationsactive malignancy, pregnancyactive malignancy, pregnancy

Which has more behind it

Ipamorelin carries the stronger evidence grade (C) against GHRP-6 at D, which means more of what is claimed for Ipamorelin has been tested in humans. Both entries link through to the full reference, where the trial list and citations for each claim are set out in full.

Full Ipamorelin reference · Full GHRP-6 reference

At a glance

CompoundGradeReported doseHalf-life
IpamorelinCgrade200–300 mcg · 1-3x daily~2 hours
GHRP-6Dgrade100–300 mcg · 1-3x daily~15-30 min

Frequently asked questions

Ipamorelin or GHRP-6, which has better evidence?

Ipamorelin carries the stronger evidence grade (C) against GHRP-6 at D, which means more of what is claimed for Ipamorelin has been tested in humans.

Can Ipamorelin and GHRP-6 be used together?

The catalog does not list Ipamorelin and GHRP-6 as a common pairing. Combining compounds does not combine their evidence.

What doses are reported for Ipamorelin?

Published protocols report 200–300 mcg, 1-3x daily. This is what the literature describes, not a recommendation.

References

  1. Ipamorelin, the first selective growth hormone secretagogue · Raun K, et al. · 1998
  2. Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients. · Beck DE, Sweeney WB, McCarter MD et al. · 2014
  3. Ipamorelin | C38H49N9O5 | CID 9831659 - PubChem - NIH
  4. Hansen BS, et al. The growth hormone secretagogue ipamorelin: pharmacological profile. Endocrinology. 1999;140(11):5552-5561. · Cowen ME, Miles BJ, Cahill DF, Giesler RB, Beck JR, Kattan MW · 1998
  5. Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers. · Gobburu JV, Agersø H, Jusko WJ et al. · 1999
  6. Johansen PB, et al. Ipamorelin, a new growth-hormone-releasing peptide, induces longitudinal bone growth in rats. Growth Hormone & IGF Research. 1999;9(2):106-113. · Johansen PB, Nowak J, Skjaerbaek C, Flyvbjerg A, Andreassen TT, Wilken M, Orskov H · 1999
  7. Determination of growth hormone releasing peptides metabolites in human urine after nasal administration of GHRP-1, GHRP-2, GHRP-6, Hexarelin, and Ipamorelin. · Semenistaya E, Zvereva I, Thomas A et al. · 2015
  8. Svensson J, et al. Effects of growth hormone secretagogues on bone. Endocrine. 2001;14(1):63-66. · Heffernan M, Summers RJ, Thorburn A, Ogru E, Gianello R, Jiang WJ, Ng FM · 2001
  9. A high-throughput LC-MS/MS screen for GHRP in equine and human urine, featuring peptide derivatization for improved chromatography. · Timms M, Hall N, Levina V et al. · 2014
  10. Efficacy of ipamorelin, a ghrelin mimetic, on gastric dysmotility in a ... · Greenwood-Van Meerveld B, Tyler K, Mohammadi E, Pietra C · 2012
  11. Beck DE, et al. Prospective, randomized, controlled, proof-of-concept study of the ghrelin mimetic ipamorelin for postoperative ileus. Journal of Gastrointestinal Surgery. 2008;12(7):1223-1231. · Akramiene D, Kondrotas A, Didziapetriene J, Kevelaitis E · 2007
  12. GHRP-6 and the discovery of the ghrelin receptor · Bowers CY · 2012
  13. Bowers CY, et al. On the in vitro and in vivo activity of a new synthetic hexapeptide that acts on the pituitary to specifically release growth hormone. Endocrinology. 1984;114(5):1537-1545. · Bowers CY, Momany FA, Reynolds GA, Hong A · 1984
  14. Acute dexamethasone administration enhances GH responsiveness to GH releasing peptide-6 (GHRP-6) in man. · Pinto AC, Finamor FE Jr, Lengyel AM · 1999
  15. Howard AD, et al. A receptor in pituitary and hypothalamus that functions in growth hormone release. Science. 1996;273(5277):974-977. · Howard AD, Feighner SD, Cully DF, Arena JP, Liberator PA, Rosenblum CI, Hamelin M, Hreniuk DL, Palyha OC, Anderson J, Paress PS, Diaz C, Chou M, Liu KK, McKee KK, Pong SS, Chaung LY, Elbrecht A, Dashkevicz M, Heavens R, Rigby M, Sirinathsinghji DJ, Dean DC, Melillo DG, Patchett AA, Nargund R, Griffin PR, DeMartino JA, Gupta SK, Schaeffer JM, Smith RG, Van der Ploeg LH · 1996
  16. Growth hormone response to GHRH, GHRP-6 and GHRH + GHRP-6 in patients with polycystic ovary syndrome. · Micić D, Kendereski A, Popović V et al. · 1996
  17. Synthetic Growth Hormone-Releasing Peptides (GHRPs) - NIH · Berlanga-Acosta J, Abreu-Cruz A, Herrera DGB, Mendoza-Marí Y, Rodríguez-Ulloa A, García-Ojalvo A, Falcón-Cama V, Hernández-Bernal F, Beichen Q, Guillén-Nieto G · 2017
  18. Kojima M, Kangawa K. Ghrelin: structure and function. Physiological Reviews. 2005;85(2):495-522. · Kojima M, Kangawa K · 2005
  19. Growth hormone secretion elicited by GHRH, GHRP-6 or GHRH plus GHRP-6 in patients with microprolactinoma and macroprolactinoma before and after bromocriptine therapy. · Popovic V, Simic M, Ilic L et al. · 1998
  20. Pharmacokinetic study of Growth Hormone-Releasing Peptide 6 ...
  21. 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. · Popovic V, Damjanovic S, Micic D et al. · 1995
  22. Growth hormone releasing peptide-6 (GHRP-6) prevents ... · Berlanga-Acosta J, Cibrian D, Valiente-Mustelier J, Suárez-Alba J, García-Ojalvo A, Falcón-Cama V, Jiang B, Wang L, Guillén-Nieto G · 2024
  23. Leal-Cerro A, et al. Growth hormone (GH)-releasing peptide-6 requires endogenous hypothalamic GH-releasing hormone for maximal GH stimulation. J Clin Endocrinol Metab. 1998;83(4):1186-1189. · Pandya N, DeMott-Friberg R, Bowers CY, Barkan AL, Jaffe CA · 1998
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