Japan approved pralmorelin (GHRP-2; brand GHRP Kaken 100, Kaken Pharmaceutical) on October 22, 2004 as an IV diagnostic agent for GH deficiency in patients aged 4 years and older.
adults and children >4 years with suspected GH deficiency (Japan)
GHRP-2
Not available
Growth
GHRP-2
A peptide approved in Japan for growth-hormone testing
Not FDA-approved · not available for sale or prescriptionOverview.
GHRP-2 has never been approved as a drug in the United States, where it is sold only as an unapproved research chemical. It is a synthetic hexapeptide ghrelin-receptor agonist developed at Tulane University. Under the name pralmorelin it is approved in Japan as a diagnostic agent for growth-hormone deficiency.
Also known as Pralmorelin · KP-102 · GPA-748
The molecule, decoded.
- Sequence
-
D-Ala-D-2-Nal-Ala-Trp-D-Phe-Lys-NH2
- Length
- 6 residues
- Molecular weight
- 818 g/mol
- Formula
- C45H55N9O6
- CAS number
- 158861-67-7
- Half-life
- Not established
- Routes studied
- intravenous (diagnostic testing, Japan), intranasal (studied), subcutaneous (unapproved research-chemical use)
- Modifications
- D-amino acids at positions 1, 2 and 5; D-2-naphthylalanine at position 2; C-terminal amide
How it works.
Agonizes the ghrelin receptor (GHS-R1a) on pituitary somatotrophs and hypothalamic neurons, triggering GH release together with secondary, comparatively modest elevations in cortisol, ACTH and prolactin, and mild appetite stimulation via ghrelin-pathway crosstalk.
Evidence · Approved outside the US (Japan, diagnostic use) · limited evidence
What the research shows
A pediatric study of the GHRP-2 stimulation test established diagnostic peak-GH cutoffs for GH deficiency, with sensitivity/specificity trade-offs described for different thresholds.
children evaluated for GH deficiency
In 36 patients with hypothalamic-pituitary disorders in Japan, the ACTH response during the GHRP-2 test helped screen for secondary adrenal insufficiency (cutoff 1.55-fold rise: 83% sensitivity, 88% specificity); the authors recommend measuring ACTH as well as GH during the test.
36 patients with hypothalamic-pituitary disorders (Japan)
A comparative human study found that both GHRP-2 and hexarelin stimulate GH release and also affect prolactin, ACTH and cortisol, contrasted against GHRH, TRH and hCRH.
adult volunteers
A class-wide review of GH secretagogues, including GHRPs, found insufficient long-term human safety data and a recurring glucose/insulin-sensitivity signal.
mixed adult populations
What to know first.
Based on: Japan's diagnostic-use label and small human diagnostic studies; no US efficacy or safety trials.
Reported side effects
- adverse reactions in 37.9% (86/227) of subjects in Japanese pre-approval trials, mainly borborygmi, feeling hot/flushing, sweating and increased white-cell count
- mild cortisol/ACTH/prolactin elevation
- appetite stimulation
- FDA-cited serious adverse event reports: increased insulin requirement, deaths of critically ill study subjects, infection and pancreatitis (causality not established)
Cautions
- FDA-cited immunogenicity concern for injectable/nasal compounded formulations
- not evaluated in large Western safety trials
- class-wide glucose/insulin-sensitivity concerns
Checked 2026-09
Where it stands.
Not FDA-approved · not available for sale or prescription. GHRP-2 is not FDA-approved and is not available for sale or prescription. We profile it because people ask about it.
- FDA
- Not approved in the US. Approved in Japan as a diagnostic agent (pralmorelin, PMDA, October 2004).
- Approved products
- GHRP (Kaken) / Pralmorelin (PMDA, Japan, 2004): diagnostic test for GH deficiency in adults and children over 4 (Japan only)
- Compounding
- GHRP-2 was placed in Category 2 under FDA's 503B (outsourcing facility) interim policy only, for injectable and nasal routes, on September 29, 2023, and remains there as of FDA's April 22, 2026 update; FDA cites immunogenicity risk, an unnatural amino acid that complicates characterization, and reports of serious adverse events (increased insulin requirement, deaths of critically ill study subjects, infection, pancreatitis; causality not established). GHRP-2 for other routes is in 503B Category 1. Under 503A it has never been in Category 2: FDA lists it in 503A Category 3 ('nominated without adequate support', list updated May 14, 2026), and it is not eligible for 503A compounding.
- Sport (WADA)
- Prohibited at all times under S2 (GH-releasing peptides / GHRPs) of the WADA Prohibited List, naming 'GHRP-2 (pralmorelin)' explicitly.
- Enforcement
- FDA 503B Category 2 listing (injectable and nasal routes), Sept 29, 2023, still in effect per fda.gov (updated Apr 22, 2026); 503A status is Category 3 (nominated without adequate support)
- FDA warning letter to Tailor Made Compounding (Apr 1, 2020) cited compounding with GHRP-2 among peptides not eligible under 503A