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approvedGrowth Hormone

Pralmorelin

Also known as: GHRP-2 diagnostic, KP-102, GPA-748

Pralmorelin is a synthetic hexapeptide growth hormone secretagogue approved in Japan as a diagnostic agent for growth hormone deficiency. Pharmacologically identical to GHRP-2 (Growth Hormone Releasing Peptide-2), pralmorelin is the pharmaceutical-grade formulation used in clinical diagnostic testing. A single intravenous dose stimulates GH release through the ghrelin receptor (GHS-R1a), with the GH response measured at 15, 30, 45, and 60 minutes to assess pituitary GH reserve.

4 cited references·5 researched benefits

Quick Answer

Pralmorelin is the pharmaceutical-grade form of GHRP-2, approved in Japan as a diagnostic agent for growth hormone deficiency. Administered as a single intravenous injection, it stimulates pituitary GH release through the ghrelin receptor (GHS-R1a). The GH response measured at 15–60 minutes differentiates GH-deficient from GH-sufficient patients. Unlike the insulin tolerance test, it does not cause hypoglycemia, offering a safer diagnostic alternative with high sensitivity and specificity.

Key Facts

Mechanism
Pralmorelin (GHRP-2) is a synthetic hexapeptide (D-Ala-D-2Nal-Ala-Trp-D-Phe-Lys-NH₂) that agonizes the growth hormone secretagogue receptor 1a (GHS-R1a) on anterior pituitary somatotrophs. Receptor binding activates phospholipase C via Gq/11, generating IP3-mediated calcium release from intracellular stores and opening L-type calcium channels, triggering GH exocytosis. Pralmorelin also suppresses somatostatin release from the hypothalamus, removing tonic GH inhibition and amplifying the secretory response. Peak GH levels occur 15–30 minutes post-IV injection, with the magnitude of response reflecting pituitary somatotroph reserve.
Research Status
approved
Half-Life
~25 minutes
Molecular Formula
C₄₅H₅₅N₉O₆
Primary Use
Growth Hormone
Table of Contents

Benefits

  • GH deficiency diagnosis — approved diagnostic test in Japan with high sensitivity and specificity for adult and pediatric GH deficiencystrong
  • Safety advantage — no hypoglycemia risk compared to insulin tolerance test, the traditional gold standardstrong
  • Rapid results — GH response peaks within 15–30 minutes, with complete test in 60 minutesstrong
  • Potent GH release — among the strongest GH secretagogues, producing robust and reproducible GH responsesstrong
  • Synergy with GHRH — combining pralmorelin with GHRH (GHRP-2 + GHRH test) provides the most potent GH stimulation test availablemoderate

Dosage Protocols

RouteDosage RangeFrequencyNotes
Intravenous injection (diagnostic)1 mcg/kg body weight (max 100 mcg)Single doseAdministered as a single IV bolus for diagnostic testing. Patient must fast overnight. Blood samples collected at 0, 15, 30, 45, and 60 minutes. GH peak below defined cutoff confirms GH deficiency.
Subcutaneous injection (research/off-label)100–300 mcg1–3× dailyResearch use of GHRP-2. Often combined with Modified GRF 1-29 for synergistic GH release. Not approved for therapeutic use in any country.

Medical disclaimer

Dosage information is provided for educational reference only. Always follow your prescriber's instructions and consult a qualified healthcare provider before starting any peptide protocol.

Side Effects

  • Facial flushing — transient warmth and redness immediately after injection, lasting 5–10 minutescommon
  • Increased appetite — acute hunger sensation within 20–30 minutes of administrationcommon
  • Cortisol and prolactin elevation — pralmorelin also stimulates ACTH/cortisol and prolactin release, an effect not seen with all GH secretagoguescommon
  • Dizziness — mild lightheadedness in some patients during the testrare
  • Injection-site reaction — mild pain or erythema at IV injection sitecommon

Frequently Asked Questions

Is pralmorelin the same as GHRP-2?
Yes, pralmorelin is the International Nonproprietary Name (INN) for GHRP-2 (Growth Hormone Releasing Peptide-2). They are the same molecule: D-Ala-D-2Nal-Ala-Trp-D-Phe-Lys-NH₂. "Pralmorelin" is the pharmaceutical-grade designation used in the approved Japanese diagnostic product, while "GHRP-2" is the common research name used in the peptide research community. The diagnostic formulation meets pharmaceutical manufacturing standards (GMP), while research-grade GHRP-2 varies in purity.
How does the pralmorelin test compare to the insulin tolerance test?
The insulin tolerance test (ITT) induces hypoglycemia (blood glucose <40 mg/dL) to trigger a stress-mediated GH response, carrying risks of seizures, loss of consciousness, and cardiovascular events. The pralmorelin test directly stimulates pituitary somatotrophs without hypoglycemia, making it safer for patients with cardiovascular disease, epilepsy, or elderly patients. Diagnostic accuracy is comparable (sensitivity >90%), though the ITT remains the reference standard in some guidelines because it also tests the entire hypothalamic-pituitary axis.
Why does pralmorelin also increase cortisol and prolactin?
GHRP-2/pralmorelin activates GHS-R1a not only on somatotrophs but also on corticotrophs and lactotrophs. This produces parallel ACTH/cortisol and prolactin release. This effect distinguishes GHRP-2 from more selective GH secretagogues like ipamorelin, which stimulates GH without significant cortisol or prolactin elevation. For diagnostic purposes, this broader hormonal stimulation is acceptable, but for therapeutic use, the non-selective endocrine effects of GHRP-2 are considered a disadvantage.
Is pralmorelin available outside Japan?
Pralmorelin is approved as a diagnostic agent only in Japan. In other countries, the insulin tolerance test, arginine stimulation test, glucagon stimulation test, or macimorelin test (FDA-approved in the US) are used for GH deficiency diagnosis. GHRP-2 (the same molecule) is available as a research chemical from peptide suppliers worldwide, but it lacks pharmaceutical-grade manufacturing certification and regulatory approval for clinical use outside Japan.

References

  1. 1
    Diagnostic utility of GHRP-2 (pralmorelin) for growth hormone deficiency in adults(2006)PubMed ↗
  2. 2
    GHRP-2 test for GH deficiency in children: comparison with insulin tolerance test and arginine test(2005)PubMed ↗
  3. 3
    Growth hormone-releasing peptides: clinical and basic aspects(2001)PubMed ↗
  4. 4
    Pralmorelin: a review of its use as a diagnostic agent in growth hormone deficiency(2008)PubMed ↗

Latest Research

Last updated: 2026-02-19