RESEARCH MONOGRAPH · KDC-MN-076

GHRP-2

May 9, 2026 Kodiac biolabs Research Revised May 30, 2026 2 min read

Our opinion on this compound

72/100

Solid second-generation ghrelin mimetic with cleaner cortisol profile than GHRP-6 and decent research utility

GHRP-2 (pralmorelin) is one of the cleaner second-generation growth hormone secretagogues and gets less attention than GHRP-6 in the lifter scene but more respect in the actual endocrinology literature. Developed by Bowers and colleagues at Tulane in the 90s as an extension of the GHRP-1/GHRP-6 work, the structure is a synthetic hexapeptide (D-Ala-D-2-Nal-Ala-Trp-D-Phe-Lys-NH2) that acts at GHSR1a (the ghrelin receptor) with high potency.

What we like: the cortisol and prolactin elevation is meaningfully lower than GHRP-6 at equivalent GH-release doses, which makes it a cleaner research tool when youre trying to isolate GH effects from confounding stress-axis activation. The pharmacokinetics are predictable (half-life around 15-20 minutes, peak GH response within 15 minutes of injection), and the combination with GHRH-class peptides (sermorelin, CJC-1295 without DAC) gives a synergistic pulse that mimics endogenous secretion patterns better than either alone. For studying GH-IGF-1 axis pharmacology in animal models or human cell culture systems, GHRP-2 is a workhorse.

What we dont like: oral bioavailability is poor, so research applications are mostly parenteral, which limits convenience. And the appetite stimulation, while less than GHRP-6, is still significant for some subjects (probably about half the magnitude of GHRP-6 ghrelin receptor activation on hypothalamic feeding circuits). Tachyphylaxis develops with repeated dosing, so chronic protocols need careful design.

Sourcing is reasonably good but not perfect. The hexapeptide synthesis is standard Fmoc-SPPS, HPLC purity above 98% is achievable, and reputable peptide vendors handle this well. Watch for the common issue of incomplete deprotection or oxidation of the tryptophan residue which shows up in cheaper lots.

For GH secretagogue research, particularly when paired with a GHRH analog for combination work, GHRP-2 is a sensible choice and frankly more useful than the more famous GHRP-6 for most applications. The cleaner cortisol profile is the underappreciated angle.

Evidence: 65
Mechanism: 82
Reliability: 75
Safety: 75
Sourcing: 78
Value: 72
Signal: 70
Staying power: 62

Plain-language summary Intrigue 60 / 100

GHRP-2 is a synthetic peptide that activates the ghrelin receptor and triggers growth hormone release. It is a stronger growth hormone releaser than ipamorelin but also raises cortisol and prolactin slightly. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

Growth hormone releasing peptide / ghrelin receptor agonist

A second-generation hexapeptide ghrelin receptor agonist for growth hormone release, characterized by stronger GH stimulation than GHRP-6 with reduced cortisol/prolactin elevation.

Abstract

GHRP-2 (Pralmorelin; D-Ala-D-2-Naphthyl-Ala-Ala-Trp-D-Phe-Lys-NH2; CAS 158861-67-7; molecular formula C45H55N9O6; molecular weight 817.97) is a second-generation growth hormone releasing peptide developed in the 1990s as a synthetic ghrelin receptor (GHS-R1a) agonist. The compound stimulates pituitary GH release through a mechanism distinct from GHRH (different receptor; synergistic when combined with GHRH or GHRH analogs). GHRP-2 produces robust GH pulses approximately 2 to 5 times baseline with parenteral administration. Pharmacokinetics: plasma half-life 15 to 60 minutes; subcutaneous and intravenous routes; oral bioavailability poor due to peptidase degradation. The compound is used clinically in Japan as a GH stimulation test. Compared with GHRP-6, GHRP-2 produces stronger GH release with reduced cortisol and prolactin elevation. Compared with ipamorelin, GHRP-2 has higher GH efficacy but less receptor selectivity. Reported research dose ranges in the literature are described in the source monograph.

Mechanism of action

Ghrelin receptor (GHS-R1a) agonist. Stimulates pituitary GH release. Synergistic with GHRH analogs.

Reported research dose ranges

100 to 300 micrograms SC.

References

Bowers CY, et al. Growth hormone releasing peptides: structure-activity. Endocrinol 1991.
Smith RG, et al. Pralmorelin: pharmacology of growth hormone secretagogues. Endocr Rev 1997.

Read the full monograph

The full reference document covers compound identification, discovery and developmental history, mechanism of action, pharmacokinetics, reported research dose ranges, sourcing and quality verification, reconstitution and handling, stack interaction considerations, and a curated reference list. Available as a research-use-only PDF download.

KDC-MN-076

The full reference document is provided strictly for research use only. It reports research dose ranges from the published literature, not instructions for use in humans or animals.

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FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

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GHRP-2

Abstract

Mechanism of action

Reported research dose ranges

References

Read the full monograph

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Abstract

Mechanism of action

Reported research dose ranges

References

Read the full monograph

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