GHRP-2What the studies show
The potent GHRP approved in Japan as a one-dose test for growth hormone deficiency, and shown to make healthy men eat about a third more at a single meal.
5 min read · Small human studies · Updated November 2026
In short
- Name
- GHRP-2 (pralmorelin)
- Evidence
- Small human studies
- Bottom line
- Small human hormone studies in children and adults, a diagnostic approval in Japan based on single doses, one uncontrolled eight-month growth study and one single-meal appetite study; nothing placebo-controlled for any therapeutic use.
Before you read this
This guide explains what published studies found. That is all it is.
It is not medical advice and it is not instructions for using anything. Where a dose appears, we are reporting what a named study gave the people or animals in it — a fact about the study, not an instruction to you.
The compounds here are not approved by the FDA for use in people and are sold for laboratory research only. A study tells you what happened to the subjects in it; it does not tell you what would happen to you. Talk to a doctor first.
What it is
GHRP-2, also called pralmorelin, is a six-amino-acid peptide from Cyril Bowers' laboratory, the same group that made GHRP-6. Three of its residues are in the D form, including a D-2-naphthylalanine that makes it the most potent of the early GHRPs at releasing growth hormone. Like the others it acts on the ghrelin receptor, and like GHRP-6 it also raises ACTH and cortisol, a point made directly in the 1998 paper that introduced ipamorelin as the first GHRP that did not 1. Kaken Pharmaceutical developed it in Japan under the code KP-102, and it is approved there as a diagnostic agent: a single intravenous dose, with the growth hormone response measured afterward, used to test whether a patient's pituitary can release growth hormone 2. It is not approved as a treatment anywhere.
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As a test
The diagnostic use is the best-documented part of the record. A 2007 study in the European Journal of Endocrinology, from the Japanese group behind the approval, gave a single intravenous dose of GHRP-2 to adults with confirmed growth hormone deficiency and to controls, and found that a cut-off on the peak growth hormone level separated the two groups cleanly, with a simpler and shorter procedure than the insulin tolerance test that is the usual standard 2. A diagnostic test is a different thing from a therapy: it depends on the drug producing a large, reliable, one-time response, which GHRP-2 does.
In children
A 1998 phase 1 study measured GHRP-2's pharmacokinetics and the growth hormone response in children with short stature, and found the response rose with dose and the peptide was tolerated at the doses given 3. In the same year, a Chilean and American group reported an eight-month study in which growth-hormone-deficient children received graded doses of GHRP-2 under the skin, and found that growth velocity increased during treatment in the children studied 4. The study was small and had no placebo arm, so it establishes that growth can respond, not how much or how reliably.
Appetite
The ghrelin receptor is also the hunger receptor, and GHRP-2 is the GHRP for which that was measured most directly in people. In a 2005 study, healthy men received an infusion of GHRP-2 or saline and were then offered a buffet meal; on GHRP-2 they ate about a third more than on saline, with the usual rise in growth hormone alongside 5. The effect was on food eaten, in a single session. It says nothing about weight over time, but it does establish that the appetite effect of this class is real in humans and not only in rats. The meal came during the infusion; what happens to appetite between doses, or after weeks of them, was not measured.
What is not known
There is no placebo-controlled trial of GHRP-2 as a treatment for anything, in children or adults, and no study of body composition, strength or ageing in healthy people. The cortisol and prolactin rise has been measured acutely but not over months. The children in the growth study were followed for eight months and then the record stops: there is no published report of their final height, and no controlled comparison with growth hormone itself, the treatment such children would normally receive. The Japanese approval covers a single diagnostic dose and nothing else, and the pharmacology that makes it a good test, a big one-off release, is not evidence about repeated use.
What these studies are, and aren't
Small human studies. Small human hormone studies in children and adults, a diagnostic approval in Japan based on single doses, one uncontrolled eight-month growth study and one single-meal appetite study; nothing placebo-controlled for any therapeutic use.
Sources
- 1Raun K et al. Ipamorelin, the first selective growth hormone secretagogue. European Journal of Endocrinology, 1998.
- 2Chihara K et al. A simple diagnostic test using GH-releasing peptide-2 in adult GH deficiency. European Journal of Endocrinology, 2007.
- 3Pihoker C, Kearns GL, French D, Bowers CY. Pharmacokinetics and pharmacodynamics of growth hormone-releasing peptide-2: a phase I study in children. Journal of Clinical Endocrinology & Metabolism, 1998.
- 4Mericq V et al. Effects of eight months treatment with graded doses of a growth hormone (GH)-releasing peptide in GH-deficient children. Journal of Clinical Endocrinology & Metabolism, 1998.
- 5Laferrère B et al. Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men. Journal of Clinical Endocrinology & Metabolism, 2005.
More in Growth hormone axis
- CJC-1295 (no DAC): What the Studies ShowSermorelin with four amino acids swapped to survive the blood longer, and without the albumin-binding tail that gave the DAC version its week-long half-life.
- CJC-1295 + Ipamorelin: What the Studies ShowTwo peptides for two receptors on the same pituitary cell. The idea comes from a 1990 study in men; the pair itself has never been tested together.
- CJC-1295 with DAC: What the Studies ShowA GHRH analogue that bonds to albumin in the blood: one injection raised growth hormone for about a week in healthy adults, with the normal pulses intact.
- GHRP-6: What the Studies ShowThe 1984 hexapeptide that came before its own receptor and before ghrelin — and the reason the hunger it causes is the receptor doing its job.
- Hexarelin: What the Studies ShowGHRP-6 with one methyl group added, active by mouth and nose as well as by injection, and the GHRP whose growth hormone response was shown to fade by 16 weeks.