What Is GHRP-2? Definition and What Research Reports
GHRP-2, also called pralmorelin, is a small synthetic peptide that acts on the same pituitary receptor as ghrelin and triggers growth hormone release. It was developed as a diagnostic agent for growth hormone deficiency and has been studied in adults, children, and animals. Published research describes growth hormone responses, appetite effects, ACTH and cortisol changes, and diagnostic testing applications. This glossary entry defines the term, explains how it is used in the literature, and summarises what studies reported.
GHRP-2 is short for growth hormone-releasing peptide-2, a small laboratory-made peptide that prompts the pituitary gland to release growth hormone. It is also known by the generic name pralmorelin and by development codes such as KP-102 and GPA-748 (PMID 15230633). In plain terms, it is a synthetic molecule that mimics part of what the natural hormone ghrelin does: it binds a receptor in the brain and pituitary and, within minutes of administration, causes a measurable rise in circulating growth hormone. Its best-documented role in medicine is not as a treatment but as a diagnostic probe — a way for clinicians to test whether a person's pituitary is capable of producing growth hormone.
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What GHRP-2 Is in Biochemical Terms
GHRP-2 belongs to a class of compounds called growth hormone secretagogues (GHS). These are agents that stimulate growth hormone secretion by acting on the growth hormone secretagogue receptor (GHS-R1a) — the same receptor the stomach-derived hormone ghrelin activates. This distinguishes GHRP-2 from GHRH analogues, which act on a separate receptor (the GHRH receptor). Because the two receptor pathways are different, researchers have often used GHRP-2 and GHRH together in testing protocols to probe pituitary reserve from two directions.
Structurally, GHRP-2 is a short synthetic peptide, not a protein or a hormone that occurs naturally in the body. Its small size and peptide nature mean it is cleared quickly; chemists have explored modifications such as PEGylation to extend its presence in circulation. One study synthesised a mono-PEGylated form of GHRP-2 and investigated its biological activity, reporting that the conjugate retained growth-hormone-releasing activity while the modification altered its pharmaceutical properties (PMID 25761386).
Key identifiers
| Term | What it refers to |
|---|---|
| GHRP-2 | Growth hormone-releasing peptide-2, the common research abbreviation |
| Pralmorelin | The international generic (INN) name for the same molecule (PMID 15230633) |
| KP-102, GPA-748 | Development codes used in pharmaceutical literature (PMID 15230633) |
| GHS-R1a | The receptor GHRP-2 acts on, shared with ghrelin |
| Secretagogue | General term for an agent that causes a gland to secrete a hormone |
Regulatory Status
GHRP-2 is unusual among research peptides in that it has a formal pharmaceutical identity. Under the name pralmorelin, it was profiled in the pharmaceutical development literature as a growth hormone-releasing peptide advanced toward diagnostic use (PMID 15230633). In Japan, a GHRP-2 test has been used clinically to evaluate hypothalamic-pituitary function, and a 2022 report in the Journal of the Endocrine Society examined the clinical usefulness of the GHRP-2 test for hypothalamic-pituitary disorder (PMID 35795807).
Outside of jurisdictions where a regulated diagnostic product exists, material labelled GHRP-2 is typically distributed as research-use-only (RUO) chemical and is not an approved medicine. RUO material is not manufactured, tested, or labelled to pharmaceutical standards, and its purity and identity are not verified by a regulator. GHRP-2 is also listed among substances prohibited in sport by anti-doping authorities under the growth hormone secretagogue category.
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Try it freeHow the Term Is Used in Research — and Where It Is Misused
In the published literature, "GHRP-2" almost always appears in one of three contexts: as a diagnostic stimulus in endocrine testing, as a pharmacological tool for probing the ghrelin receptor system, or as a synthesis and formulation subject in peptide chemistry. The diagnostic usage dominates. Researchers have used GHRP-2 challenges to distinguish pituitary conditions and to characterise hormone responses in defined patient groups.
The term is frequently misused in non-scientific settings in several recognisable ways:
- Treating it as growth hormone itself. GHRP-2 is not growth hormone. It is a signal that prompts the pituitary to release its own stored hormone, which means its effect depends on whether functioning pituitary tissue is present.
- Assuming it acts only on growth hormone. Published work showed that GHRP-2 also affected other pituitary outputs; one mouse study reported that GHRP-2 stimulated both secretion and synthesis of adrenocorticotropic hormone (ACTH) in the pituitary (PMID 19682503).
- Blurring it with GHRH peptides. GHRP-2 and GHRH analogues such as sermorelin or tesamorelin act on different receptors and are not interchangeable terms.
- Describing diagnostic-test data as if it were treatment data. Most human GHRP-2 studies involved single administrations in a controlled testing setting, not repeated administration over time, so they do not describe long-term outcomes.
Related Terms
- Ghrelin — the endogenous hormone whose receptor GHRP-2 activates; a human study directly compared GHRP-2's appetite effect to ghrelin's (PMID 15699539).
- GHS-R1a — the growth hormone secretagogue receptor.
- GHRH — growth hormone-releasing hormone, a separate pathway.
- GHRP-6, hexarelin, ipamorelin — other peptides in the growth hormone-releasing peptide family.
- Provocative testing — the endocrine practice of administering a stimulus and measuring the hormone response.
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Diagnostic testing in humans
The 2022 Journal of the Endocrine Society report evaluated the clinical usefulness of the GHRP-2 test for assessing hypothalamic-pituitary disorder, examining how the growth hormone response to GHRP-2 performed as a diagnostic tool in patients with pituitary disease (PMID 35795807). A separate 2018 study in Endocrine Journal evaluated GHRP-2 for the diagnosis of thyrotropin-producing pituitary adenomas, testing whether hormone responses to the peptide could help identify that specific tumour type (PMID 29973439).
In paediatric endocrinology, researchers assessed the growth hormone response to GHRP-2 in children, characterising how the peptide performed as a provocative stimulus in a younger population (PMID 20662346).
Appetite and food intake
One of the most cited human findings concerns appetite. A 2005 study in the Journal of Clinical Endocrinology and Metabolism reported that GHRP-2, like ghrelin, increased food intake in healthy men (PMID 15699539). The direction of this effect is not universal across species: an earlier study reported that chicken ghrelin and GHRP-2 inhibited food intake in neonatal chicks (PMID 12393062), illustrating why researchers caution against extrapolating appetite findings between species.
Other hormonal and cellular effects
Not every pituitary hormone responded. A 2010 study in healthy men reported that GH-releasing peptide-2 did not stimulate arginine vasopressin secretion (PMID 19907099). In contrast, mouse pituitary work reported stimulation of ACTH secretion and synthesis (PMID 19682503).
Outside the pituitary, a 2016 cell-culture study examined GHRP-2 in human ovarian granulosa cells and reported attenuation of protein kinase C-induced inflammation (PMID 27548147) — a laboratory finding in isolated cells, not a clinical outcome.
Animal and pharmacology studies
Researchers investigated the growth hormone response to GHRP-2 in growth hormone-deficient "little" mice, a genetic model with impaired GHRH signalling, to probe how much of the peptide's action depends on an intact GHRH pathway (PMID 22473409). A general pharmacology study of KP-102 (GHRP-2) surveyed its broader pharmacological profile as a potent growth hormone-releasing peptide across standard safety-pharmacology domains (PMID 15646371).
Safety and Tolerability: What Studies Report
The published record on GHRP-2 is dominated by short, single-administration diagnostic testing rather than long-term exposure, which limits what can be said about extended use. The general pharmacology study of KP-102 (GHRP-2) surveyed the peptide's pharmacological profile as part of preclinical characterisation (PMID 15646371), and the pharmaceutical development profile of pralmorelin summarised its status as a compound advanced through development (PMID 15230633). Reported off-target hormonal effects include the ACTH stimulation described in mouse pituitary tissue (PMID 19682503) and the increased food intake observed in healthy men (PMID 15699539). No long-duration human safety trial appears among the sources summarised here, and readers should treat the absence of such data as a gap rather than as reassurance.
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Start learning freeSummary of the Definition
GHRP-2 is a synthetic growth hormone secretagogue, generically named pralmorelin, that activates the ghrelin receptor and causes pituitary growth hormone release. Its established literature role is diagnostic testing of hypothalamic-pituitary function; its research literature also documents appetite effects, ACTH effects, absence of vasopressin stimulation, cell-level anti-inflammatory findings, and chemical modification work. Anyone with a medical question about growth hormone status should consult a licensed physician.
References
- Clinical Usefulness of the Growth Hormone-Releasing Peptide-2 Test for Hypothalamic-Pituitary Disorder (Journal of the Endocrine Society, 2022)
- Evaluation of growth hormone-releasing peptide-2 for diagnosis of thyrotropin-producing pituitary adenomas (Endocrine Journal, 2018)
- Pralmorelin: GHRP 2, GPA 748, growth hormone-releasing peptide 2, KP-102 (Drugs in R&D, 2004)
- Growth Hormone Releasing Peptide-2 Attenuation of Protein Kinase C-Induced Inflammation in Human Ovarian Granulosa Cells (International Journal of Molecular Sciences, 2016)
- GH-releasing peptide-2 does not stimulate arginine vasopressin secretion in healthy men (Endocrine Journal, 2010)
- Synthesis of Mono-PEGylated Growth Hormone Releasing Peptide-2 and Investigation of its Biological Activity (AAPS PharmSciTech, 2015)
- Growth hormone response to GH-releasing peptide-2 in children (Journal of Pediatric Endocrinology & Metabolism, 2010)
- Growth hormone-releasing peptide-2 stimulates secretion and synthesis of adrenocorticotropic hormone in mouse pituitary (Regulatory Peptides, 2009)
- Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men (Journal of Clinical Endocrinology and Metabolism, 2005)
- Growth hormone response to growth hormone-releasing peptide-2 in growth hormone-deficient little mice (Clinics, 2012)
- Chicken ghrelin and growth hormone-releasing peptide-2 inhibit food intake of neonatal chicks (European Journal of Pharmacology, 2002)
- General pharmacology of KP-102 (GHRP-2), a potent growth hormone-releasing peptide (Arzneimittel-Forschung, 2004)
Frequently asked questions
What does GHRP-2 stand for?▾
GHRP-2 stands for growth hormone-releasing peptide-2. It is a synthetic peptide also known by the generic name pralmorelin and by development codes including KP-102 and GPA-748, as catalogued in the pharmaceutical development literature (PMID 15230633). It is classified as a growth hormone secretagogue because it prompts the pituitary to release its own growth hormone.
Is GHRP-2 the same as growth hormone?▾
No. Growth hormone is a large protein hormone produced by the pituitary. GHRP-2 is a much smaller synthetic peptide that acts on the growth hormone secretagogue receptor to trigger release of stored pituitary growth hormone. Studies used it as a provocative stimulus to test pituitary capacity, including in patients with hypothalamic-pituitary disorder (PMID 35795807).
Why is GHRP-2 used in diagnostic testing?▾
Because it produces a rapid, measurable growth hormone rise, researchers used it to assess whether the pituitary can respond. A 2022 report evaluated the GHRP-2 test's clinical usefulness in hypothalamic-pituitary disorder (PMID 35795807), and a 2018 study evaluated it for diagnosing thyrotropin-producing pituitary adenomas (PMID 29973439). A separate study assessed the growth hormone response in children (PMID 20662346).
How is GHRP-2 related to ghrelin?▾
GHRP-2 acts on GHS-R1a, the same receptor activated by the natural hormone ghrelin. Researchers reported that GHRP-2, like ghrelin, increased food intake in healthy men (PMID 15699539). Species differences exist: an earlier study reported that chicken ghrelin and GHRP-2 inhibited food intake in neonatal chicks (PMID 12393062), so appetite findings do not transfer across species.
Does GHRP-2 affect hormones other than growth hormone?▾
Published work suggests it is not entirely selective. A mouse pituitary study reported that GHRP-2 stimulated both secretion and synthesis of adrenocorticotropic hormone (PMID 19682503). By contrast, a study in healthy men reported that GHRP-2 did not stimulate arginine vasopressin secretion (PMID 19907099). These findings describe specific experimental settings, not general clinical outcomes.
What is the regulatory status of GHRP-2?▾
Under the generic name pralmorelin, GHRP-2 was developed as a pharmaceutical agent and has been used clinically in some jurisdictions as a diagnostic test for pituitary function (PMID 15230633; PMID 35795807). Elsewhere, material labelled GHRP-2 is generally distributed as research-use-only chemical and is not an approved medicine. It is also prohibited in sport by anti-doping authorities.
What does the literature not answer about GHRP-2?▾
Most human studies involved short, single-administration diagnostic testing rather than prolonged exposure, so long-term human safety and outcome data are limited among the papers summarised here. Preclinical work included a general pharmacology survey of KP-102 (PMID 15646371) and chemistry work on a PEGylated form (PMID 25761386). This page is educational only and is not medical advice.
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References
This page summarises published research for education — it is not medical advice, and nothing here is a recommendation to use, purchase, or dose any substance. Study parameters described are what researchers reported, not instructions. Consult a qualified clinician before any health decision.