GHRP-2, also called pralmorelin, is a lab-made peptide, six amino acids long, that activates the ghrelin receptor and makes the pituitary gland release a burst of growth hormone. Unlike most peptides in its family, it has an approved medical use: since 2004, Japan has allowed it as a one-time IV test for growth hormone deficiency, sold by Kaken Pharmaceutical.[1][2] We found no FDA approval, and FDA lists injectable and nasal GHRP-2 among compounding substances that may present significant safety risks.[15]
This profile covers what GHRP-2 is, how it is used in Japan, what human studies found on growth hormone, hunger and growth, side effects, doses studied, comparisons with related peptides, and its legal status.
What is GHRP-2?
GHRP-2 belongs to a group of synthetic peptides called growth hormone-releasing peptides (GHRPs), built as more potent successors to the original, GHRP-6.[4][5] It contains an unnatural amino acid, a feature FDA says makes the peptide harder to characterize in compounded products.[15]
Japan’s label explains that GHRP-2 binds the growth hormone secretagogue receptor and acts mainly through the hypothalamus to make the pituitary release growth hormone.[2] Its effect is brief: after IV doses in 18 healthy men, its elimination half-life was about 0.42 to 0.69 hours, and no metabolites were found in the blood.[2] A US study in children measured about 33 minutes.[11]
GHRP-2 in Japan: a diagnostic test
Japan approved pralmorelin on October 22, 2004, and Kaken launched it as GHRP Kaken 100 in February 2005.[1][2] The label permits one use: diagnosing growth hormone deficiency.[2]
- How it is given: 100 mcg by slow IV injection after fasting in adults; 2 mcg/kg (up to 100 mcg) in children aged 4 to 17.[2]
- How it is read: blood is drawn before the dose and at 15, 30, 45 and 60 minutes. A peak growth hormone level of 15 ng/mL or less (9 ng/mL with newer recombinant standards) points to severe deficiency.[2]
In the validation study, run by the Japanese KP-102 Study Group and led from Kobe University, in 77 healthy adults and 58 adults with severe deficiency, the average peak after 100 mcg was 84.6 micrograms per liter in healthy people versus 1.36 in patients. A 15 microgram cut-off matched the standard insulin tolerance test, which can be dangerous for some patients.[3]
GHRP-2 benefits: what human research shows
Growth hormone release
In a head-to-head study in Turin, 1 mcg/kg IV GHRP-2 and hexarelin released similar, strong amounts of growth hormone, more than GHRH did.[5] In Belgium, a 21-hour infusion in 26 critically ill adults raised growth hormone 4- to 6-fold and IGF-1 by 61% within 24 hours.[12] In 10 older US adults with low growth hormone, a 30-day continuous infusion under the skin kept IGF-1 raised throughout.[13]
Hunger and food intake
GHRP-2 is one of the few ghrelin-type peptides tested for hunger in controlled human studies:
- Healthy men (New York): during a 270-minute infusion under the skin, seven men ate 35.9% more at a buffet than on saline, and every one ate more.[6]
- Lean and obese adults: a follow-up in 19 people found a dose-related rise of 10% at a low dose and 34% at a high dose, regardless of weight.[7]
- Children (Chile): 7 of 10 children taking GHRP-2 by mouth for a year reported more appetite in the first 6 months, but their BMI score did not rise significantly.[8]
Growth in children
In 15 US children with short stature, a nasal spray twice to three times daily raised height velocity from 3.7 to about 6 cm a year, without raising IGF-1.[9] In six Chilean children with growth hormone deficiency, eight months of injections increased growth velocity, though the effect of each dose was brief.[10] Neither was a placebo-controlled trial, and GHRP-2 was never approved for growth.
GHRP-2 side effects
From Japan’s label: a feeling of warmth was the most common reaction, in 16.0% of people tested. The label also lists sweating, thirst, hunger, feeling dazed, tiredness, drowsiness, nausea, stomach discomfort, bloating, runny nose, raised ALT (a liver enzyme), low blood pressure, headache and facial flushing.[2] It must not be used in pregnancy, and the label warns that similar drugs given to people with pituitary tumors have caused pituitary bleeding (apoplexy).[2]
Hormone effects: GHRP-2 raises prolactin, ACTH and cortisol, by amounts similar to hexarelin.[5] In pigs, it raised ACTH and cortisol while ipamorelin did not.[14]
FDA’s concerns: FDA cites reports of increased insulin needs to control blood sugar, deaths of critically ill study subjects, infection and pancreatitis in people given GHRP-2, though it says causality has not been established. It also warns injectable and nasal forms may trigger immune reactions from clumped peptide or impurities.[15]
GHRP-2 dosage: what has been studied
| Setting | Dose |
|---|---|
| Japanese diagnostic test (adults) | 100 mcg IV once[2] |
| Japanese diagnostic test (children 4 to 17) | 2 mcg/kg IV once, max 100 mcg[2] |
| Hunger studies | 0.1 or 1 mcg/kg per hour under the skin for 270 minutes[7] |
| Critical illness | 1 mcg/kg IV bolus, then 1 mcg/kg per hour[12] |
| Children, nasal spray | 5 to 15 mcg/kg two to three times daily[9] |
| Children, by mouth | 900 mcg/kg twice daily[8] |
A US clinic chart review found IGF-1 rose in 14 men on testosterone who took 100 mcg of a GHRP-2, GHRP-6 and sermorelin combination three times daily; it did not measure muscle, fat or safety.[23] For converting milligrams to syringe units, see our peptide calculator.
GHRP-2 vs GHRP-6, hexarelin and ipamorelin
- GHRP-6 is the original; GHRP-2 was designed as a stronger version.[4]
- Hexarelin matched GHRP-2 for growth hormone, prolactin, ACTH and cortisol in a direct comparison.[5]
- Ipamorelin was more selective in pigs: GHRP-2 was more potent but raised ACTH and cortisol, and ipamorelin did not.[14]
See our GHRP-2 vs GHRP-6 vs hexarelin comparison and the full list on our growth hormone peptides page.
What users report
Is GHRP-2 legal?
- Japan: a prescription diagnostic drug (GHRP Kaken 100), not a treatment.[2]
- United States: we found no FDA approval.
- Outsourcing facilities (503B): FDA placed GHRP-2 for injectable and nasal use in category 2, substances that may present significant safety risks, on September 29, 2023.[15] FDA’s 503B list, last updated March 2025, keeps GHRP-2 for other routes in category 1, still under evaluation.[18]
- Traditional pharmacies (503A): FDA’s May 2026 list places GHRP-2 in category 3, nominated without adequate support.[16] FDA’s interim policy does not cover category 3 substances.[17]
- Advisory committee: GHRP-2 was not among the substances FDA’s compounding advisory committee reviewed in October 2024.[19]
- Banned in sport: WADA lists “GHRP-2 (pralmorelin)” by name, prohibited at all times.[20] A Moscow anti-doping lab detected GHRP-2 and its breakdown products in urine for up to 47 hours after a nasal dose.[21]
This is general information, not legal advice; rules differ by country and change over time.
