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GHRP-2 vs GHRP-6

How GHRP-2 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.

GHRP-2

Cgrade100–300 mcg

GHRP-2 is a synthetic growth hormone releasing peptide that mimics ghrelin to stimulate a strong pulse of growth hormone from the pituitary. It is more potent than GHRP-6 with somewhat less appetite stimulation, though it can still modestly raise cortisol and prolactin at higher doses. Like other GHRPs it is most effective stacked with a GHRH analog (e.g. CJC-1295), since the two act on different receptors and amplify each other. Used for recovery and body composition; monitor 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

 GHRP-2GHRP-6
Research gradeCgradeDgrade
Reported dose100–300 mcg100–300 mcg
Frequency1-3x daily1-3x daily
Half-life~30 min~15-30 min
Routessubcutaneoussubcutaneous
Tracked outcomesMuscle Growth, Body Composition, Sleep QualityBody Composition, Muscle Growth, Sleep Quality
Contraindicationsactive malignancy, pregnancyactive malignancy, pregnancy

Which has more behind it

GHRP-2 carries the stronger evidence grade (C) against GHRP-6 at D, which means more of what is claimed for GHRP-2 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 GHRP-2 reference · Full GHRP-6 reference

At a glance

CompoundGradeReported doseHalf-life
GHRP-2Cgrade100–300 mcg · 1-3x daily~30 min
GHRP-6Dgrade100–300 mcg · 1-3x daily~15-30 min

Frequently asked questions

GHRP-2 or GHRP-6, which has better evidence?

GHRP-2 carries the stronger evidence grade (C) against GHRP-6 at D, which means more of what is claimed for GHRP-2 has been tested in humans.

Can GHRP-2 and GHRP-6 be used together?

The catalog does not list GHRP-2 and GHRP-6 as a common pairing. Combining compounds does not combine their evidence.

What doses are reported for GHRP-2?

Published protocols report 100–300 mcg, 1-3x daily. This is what the literature describes, not a recommendation.

References

  1. Growth hormone-releasing peptide-2 stimulates GH secretion · Bowers CY · 1998
  2. Arvat E, et al. 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;18(6):885-891. · Arvat E, di Vito L, Maccagno B, Broglio F, Boghen MF, Deghenghi R, Camanni F, Ghigo E · 1997
  3. 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. · Van den Berghe G, Baxter RC, Weekers F et al. · 2002
  4. Pralmorelin: GHRP 2, GPA 748, growth hormone-releasing peptide ... · 2004
  5. Mericq V, et al. Effects of eight months treatment with graded doses of a growth hormone (GH)-releasing peptide in GH-deficient children. Journal of Clinical Endocrinology & Metabolism. 1998;83(7):2355-2360. · Mericq V, Cassorla F, Salazar T, Avila A, Iñiguez G, Bowers CY, Merriam GR · 1998
  6. Synergy of L-arginine and GHRP-2 stimulation of growth hormone in men and women: modulation by exercise. · Wideman L, Weltman JY, Patrie JT et al. · 2000
  7. Berlanga-Acosta J, et al. Synthetic growth hormone-releasing peptides (GHRPs): a historical appraisal of the evidences supporting their cytoprotective effects. Clinical Medicine Insights: Cardiology. 2017;11:1179546817694558. · 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
  8. Pharmacokinetics and pharmacodynamics of growth hormone-releasing peptide-2: a phase I study in children. · Pihoker C, Kearns GL, French D et al. · 1998
  9. Pralmorelin - an overview | ScienceDirect Topics
  10. Association between overweight and growth hormone secretion in patients with non-functioning pituitary tumors. · Seki Y, Ichihara A · 2022
  11. Pralmorelin | C45H55N9O6 | CID 6918245 - PubChem - NIH
  12. Laferrere B, et al. Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men. Journal of Clinical Endocrinology & Metabolism. 2005;90(2):611-614. · Laferrère B, Abraham C, Russell CD, Bowers CY · 2005
  13. GHRP-6 and the discovery of the ghrelin receptor · Bowers CY · 2012
  14. 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
  15. Acute dexamethasone administration enhances GH responsiveness to GH releasing peptide-6 (GHRP-6) in man. · Pinto AC, Finamor FE Jr, Lengyel AM · 1999
  16. 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
  17. 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
  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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