GHRP-2 is the one growth-hormone-releasing peptide that became a licensed medicine — but as a test, not a treatment. Japan approved pralmorelin hydrochloride to check whether the pituitary can release growth hormone, so the best-documented human dose is a single 100 mcg injection into a vein. The rest of the record is small studies from the 1990s and 2000s, most of them measuring growth hormone for hours after one dose. Medibact's GHRP-2 guide covers the molecule and its evidence; this page stays with figures.
What the human record holds
A census run on 2026-09-28:
| Source | Result |
|---|---|
| KEGG DRUG (Japan) | D02040, pralmorelin hydrochloride, trade name GHRP — diagnostic reagent for endocrine function |
| Drugs@FDA | no application |
| ClinicalTrials.gov, "GHRP-2", "GHRP2", "pralmorelin" | 0 records |
| PubMed, GHRP-2, pralmorelin or KP-102 in title/abstract | 237 records |
| … tagged as human | 147 |
| … tagged as clinical trial | 57 |
The doses in the human studies, by route:
| Use | Dose and route | Source |
|---|---|---|
| Diagnostic test (GH deficiency) | 100 mcg IV, once | Eur J Endocrinol 2007 (PMID 17609397), 135 people |
| Diagnostic test (adrenal axis) | the same test, ACTH and cortisol read | Endocr J 2016 (PMID 27020037), 47 patients |
| Daily injections, healthy men | 100 mcg SC once a day, 5 days | Eur J Endocrinol 1998 (PMID 9820615), 9 men |
| GH-deficient children | 0.3 → 1.0 → 3.0 mcg/kg/day SC, 2-month steps | J Clin Endocrinol Metab 1998 (PMID 9661608), 6 children |
| GH-deficient children, by mouth | 900 mcg/kg twice daily, 12 months | J Pediatr Endocrinol Metab 2003 (PMID 14513874), 10 children |
| Appetite study | 1 mcg/kg/h SC infusion, 270 minutes | J Clin Endocrinol Metab 2005 (PMID 15699539), 7 men |
The Japanese test compares well with the insulin tolerance test it stands in for: in 71 patients with pituitary tumours, a 2013 comparison put its sensitivity at 85.5% and specificity at 94.5% for severe adult GH deficiency (Endocr J 2013, PMID 23079545). A 2015 case report describes one woman with long-standing anorexia nervosa who used it intranasally before meals for a year and gained 6.7 kg (PMID 26401470); the abstract does not state the dose, and one patient is not a trial.
The per-kilogram figures in micrograms
| Body weight | 0.3 mcg/kg | 1 mcg/kg | 3 mcg/kg |
|---|---|---|---|
| 30 kg | 9 mcg | 30 mcg | 90 mcg |
| 50 kg | 15 mcg | 50 mcg | 150 mcg |
| 70 kg | 21 mcg | 70 mcg | 210 mcg |
These are the children's daily subcutaneous steps, converted for comparison only; the trial gave them to children, not adults. The 100 mcg flat test dose sits between the top two columns for an adult. The oral dose is a different order of magnitude: 900 mcg/kg for a 30 kg child is 27 mg per dose, a gap that reflects how little of a peptide swallowed reaches the blood intact.
What repeated dosing did
The two multi-dose injection studies point the same way. In healthy men, the GH peak to the same 100 mcg fell by 39% over five days, and IGF-I stayed where it was (22 to 25 nmol/L throughout); only osteocalcin, a marker of GH action in bone, rose. In the children, GH rose step by step with the dose but IGF-I and IGFBP-3 did not, and the authors noted the effect of each injection was brief, with little action later in the night. The dosing frequency page sets short-acting secretagogues beside the long-acting ones.
Units per vial size
GHRP-2 is counted in micrograms, so the table works in mcg/mL. Units on a U-100 syringe = mcg ÷ mcg/mL × 100. Research vials in this site's data are 5 and 10 mg:
| Amount | 5 mg + 2.5 mL (2,000 mcg/mL) | 5 mg + 2 mL (2,500 mcg/mL) | 10 mg + 3 mL (3,333 mcg/mL) | 5 mg + 1 mL or 10 mg + 2 mL (5,000 mcg/mL) |
|---|---|---|---|---|
| 70 mcg (1 mcg/kg at 70 kg) | 3.5 | 2.8 | 2.1 | 1.4 |
| 100 mcg (test dose) | 5 | 4 | 3 | 2 |
| 210 mcg (3 mcg/kg at 70 kg) | 10.5 | 8.4 | 6.3 | 4.2 |
| 300 mcg | 15 | 12 | 9 | 6 |
Readings under about 5 units put a single syringe mark close to a quarter of the amount, so the more dilute columns resolve better. A 5 mg vial at 100 mcg a day covers 50 days. The mg to mcg page covers the conversion, and the GHRP-2 calculator handles any other vial. The GHRP-6 dosage page reports the older peptide from the same research line, whose human doses are also mostly one-off intravenous tests.
What is not established
No regulator has reviewed a GHRP-2 dose for any use other than a single diagnostic injection. The studies of repeated dosing are small (six to ten people), short, and found no rise in IGF-I. Its one human appetite study, and how it compares with the older peptide it was built from, are on GHRP-2 vs GHRP-6. No human half-life figure appears in the abstracts opened for this page. Doping-control laboratories publish methods to detect it in urine (Rapid Commun Mass Spectrom 2010, PMID 20552695) and in dried blood spots (Drug Test Anal 2021, PMID 33197153). Whether a vial sold as GHRP-2 contains it, and how much, is not known without an assay. Nothing on this page is a dose or a schedule.
Sources and dates
Opened 2026-09-28: PubMed searches through NCBI E-utilities (GHRP-2, GHRP2, pralmorelin or KP-102 in title or abstract, with human, clinical-trial and dose filters) and the abstracts of PMIDs 17609397, 27020037, 23079545, 9820615, 9661608, 14513874, 15699539, 26401470, 15230633, 20552695 and 33197153; KEGG DRUG entry D02040; Drugs@FDA through openFDA; ClinicalTrials.gov v2 searches for GHRP-2, GHRP2 and pralmorelin. Per-kilogram, per-vial and unit figures are arithmetic by this site. Corrections go to the contact page.