Name: GHRP-2
Brand: Peptific
SKU: GHRP-2-STANDARD

GHRP-2 (Pralmorelin) is a synthetic hexapeptide GHS-R1a agonist approved in Japan for GH stimulation testing — a potent non-selective GHRP that stimulates GH alongside cortisol and prolactin.

Growth Hormone Peptides

GHRP-2

GHRP-2 (Pralmorelin) is a synthetic hexapeptide growth hormone secretagogue that was developed as a potent GHS-R1a agonist and validated in Phase I/II human trials by Kaken Pharmaceutical, achieving approval as a GH stimulation test agent in Japan. It is among the most rigorously characterized GHRPs in the published literature, with human pharmacokinetic and pharmacodynamic data available from its Japanese regulatory process. GHRP-2 binds the ghrelin receptor (GHS-R1a) on pituitary somatotropes, stimulating potent GH release through phospholipase C and calcium-mediated signaling pathways. Unlike ipamorelin — which is highly GH-selective — GHRP-2 also significantly stimulates cortisol, prolactin, and ACTH at doses that produce meaningful GH responses. This broader receptor profile makes it less appropriate for protocols requiring isolated GH-axis effects, but more appropriate as a reference compound for full GHS-R1a agonism research where the complete spectrum of secretagogue activity is the endpoint. In GH stimulation testing, GHRP-2 produces reproducible, robust GH pulses with a shorter active window than GHRH-based compounds — approximately 15–20 minutes in vivo. The combination of GHRP-2 with GHRH or a GHRH analog produces synergistic GH release, and this combination test (GHRP-2 + GHRH) has been studied in human diagnostic contexts for GH reserve assessment. For researchers studying GHS-R1a pharmacology, GH secretagogue potency comparisons, or GHRP-class effects on cortisol and other pituitary hormones, GHRP-2 is the reference potent non-selective GHRP with the most developed human pharmacokinetic dataset in its class. This listing is for laboratory and preclinical research purposes only. Not for human or veterinary use.

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Product definition

What is GHRP-2?

GHRP-2 (Pralmorelin) is a synthetic hexapeptide GHS-R1a agonist approved in Japan for GH stimulation testing — a potent non-selective GHRP that stimulates GH alongside cortisol and prolactin.

GHRP-2 (D-Ala-D-βNal-Ala-Trp-D-Phe-Lys-NH2) is a synthetic hexapeptide developed as a potent GHS-R1a agonist, and among the first GHRPs characterized in human subjects. Kaken Pharmaceutical's regulatory approval in Japan for GH stimulation testing provides human dose-response and pharmacokinetic data that is available in the published literature — unusual for a GHRP-class compound. The compound's GH-stimulating potency is among the highest of any characterized GHRP hexapeptide. In rodent and human studies, GHRP-2 produces dose-dependent GH release with EC50 in the nanomolar range. However, the same receptor engagement that produces GH release also activates ACTH/cortisol and prolactin secretion at effective GH doses — the pharmacological property that distinguishes it from ipamorelin's selective profile and defines its utility: GHRP-2 is appropriate for full GHS-R1a agonism research; ipamorelin is appropriate for GH-isolated research.

Research context

How is GHRP-2 described in the research literature?

GHRP-2 activates GHS-R1a (ghrelin receptor) via phospholipase C / calcium-mediated signaling, producing potent GH release. Unlike ipamorelin, GHRP-2 also significantly stimulates cortisol, prolactin, and ACTH at GH-effective doses — a non-selective GHS-R1a agonism profile useful for full GH secretagogue pharmacology research.

Compound profile

Key facts about GHRP-2

Class: Synthetic hexapeptide GHRP / GHS-R1a agonist
Amino acids: 6
Molecular weight: ~818 Da
Half-life: ~15–20 minutes in vivo
CAS: 158861-67-7
Selectivity: Non-selective — stimulates GH, cortisol, prolactin, ACTH
Clinical status: Approved in Japan for GH stimulation testing
Research category: GH secretagogue, GHS-R1a pharmacology, GH axis
Storage: Lyophilized: −20°C. Reconstituted: 2–8°C, use within 30 days

Research areas

What research areas is GHRP-2 associated with?

Japanese regulatory approval for GH stimulation testing — human pharmacokinetic data published
Among the most potent GHS-R1a agonists characterized — reference compound for maximal GH response research
Stimulates GH, cortisol, prolactin, and ACTH — appropriate for broad GHS-R1a agonism pharmacology research
~15–20 minute half-life produces sharp GH pulses with clean kinetic windows
Synergistic with GHRH analogs for combined GH pulse amplification studies
Reference non-selective GHRP for comparison against ipamorelin's selective profile in mechanistic studies

Research audience

Who researches GHRP-2?

GHRP-2 is used by researchers studying GHS-R1a pharmacology, GH secretagogue potency comparison, ACTH/cortisol co-stimulation mechanisms, pituitary hormone co-secretion, and GH axis diagnostic testing paradigms.

Preclinical research overview

What does the preclinical literature say about GHRP-2?

GHRP-2 was characterized in the early 1990s as part of the systematic development of synthetic GH secretagogues following Bowers et al.'s original discovery of the GHRP pharmacological class. Its development into a Japanese-approved GH stimulation test agent represents one of the few examples of a research GHRP reaching regulatory validation — providing a published human pharmacokinetic dataset that anchors its dose-response characterization. In comparative GHRP research, GHRP-2 serves as the 'potent non-selective' reference point against which ipamorelin's selectivity is measured. Studies directly comparing GHRP-2 and ipamorelin in the same animal models documented that ipamorelin produces equivalent or greater GH release with dramatically lower cortisol and prolactin stimulation — establishing ipamorelin's selectivity claim in the published literature. The clinical GH stimulation test use of GHRP-2 (alone and in combination with GHRH) has produced a body of human data on GH reserve assessment that is relevant to researchers studying GH deficiency mechanisms and pituitary somatotrope responsiveness.

Common questions

Frequently asked about GHRP-2

Why use GHRP-2 instead of ipamorelin for GH axis research?

The question is what you're studying. If GH-isolated effects are needed, ipamorelin's selectivity (no cortisol/prolactin co-stimulation) is the appropriate choice. If full GHS-R1a agonism — including the cortisol, prolactin, and ACTH components — is the research endpoint, GHRP-2 is appropriate. GHRP-2 also offers the highest GH peak output among characterized hexapeptide GHRPs, making it the tool when maximal GH response is required regardless of co-stimulation.

Is GHRP-2 approved for clinical use?

GHRP-2 is approved in Japan as a GH stimulation test agent (Kaken Pharmaceutical). It is not FDA-approved in the United States. The Japanese approval provides a human pharmacokinetic and pharmacodynamic dataset in the published literature, distinguishing it from most GHRP-class compounds which have only animal data.

Can GHRP-2 be combined with CJC-1295 Without DAC for research?

Yes — the GHRH+GHRP combination is well-studied. GHRP-2 paired with a GHRH analog produces synergistic GH release greater than either alone, consistent with the mechanistic model of GHRH priming (somatotrope recruitment) and GHRP amplification (GHS-R1a-mediated pulse enhancement). When cortisol/prolactin co-stimulation is an acceptable confound or is itself part of the study design, GHRP-2 is a valid GHRP partner for this combination.

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