Also known as: Pralmorelin, KP-102, Growth Hormone Releasing Peptide 2
Half-life: ~15-60 minutes
Last reviewed: · Published:
GHRP-2 (also known as Pralmorelin or KP-102) is a second-generation synthetic hexapeptide that acts as an agonist of the growth hormone secretagogue receptor (GHS-R1a). Compared to its predecessor GHRP-6, it produces a stronger, more reliable pulse of growth hormone at equivalent doses and causes substantially less appetite stimulation, making it more useful in body-composition contexts where additional hunger is unwanted. It still elevates prolactin and cortisol, though to a lesser degree than GHRP-6.
GHRP-2 is one of the few growth hormone secretagogues to have been formally approved as a clinical diagnostic agent: in Japan it is registered as Pralmorelin (brand name GHRP Kaken) and used as a single-dose challenge test to evaluate adult growth hormone deficiency. The diagnostic test takes advantage of the peptide's rapid, predictable GH-releasing effect to distinguish patients with intact pituitary function from those with somatotrope failure.
In peptide-optimization protocols, GHRP-2 is commonly stacked with a GHRH analog such as CJC-1295 (Mod GRF 1-29) to drive synergistic GH release: the GHRH side increases the GH wave amplitude while the GHRP side increases pulse frequency and removes somatostatin's brake on secretion. The combination produces noticeably larger pulses than either component alone.
GHRP-2 was developed in the 1990s by the same research lineage at Tulane University that produced GHRP-6, with the goal of improving potency and reducing the off-target hormonal effects of the first-generation hexapeptide. It was licensed to Kaken Pharmaceutical in Japan, which carried it through clinical development as a diagnostic test for adult GH deficiency. Pralmorelin was approved in Japan in 2006 for this indication, making it one of the only GHRPs with any regulatory approval anywhere in the world. Outside of Japan it has remained a research compound.
GHRP-2 sits between GHRP-6 and Ipamorelin on the cleanliness scale: more potent than Ipamorelin but with a noticeably better side-effect profile than GHRP-6. The most common subjective effects are a brief head-rush feeling within minutes of injection and a mild appetite bump. Prolactin and cortisol elevations are real but usually clinically insignificant at typical doses (100 mcg). The Japanese diagnostic approval — granted after standard pharmaceutical safety review — supports the conclusion that single doses are well-tolerated in healthy adults.
Dose Range
100 mcg
Frequency
Two to three times daily (SubQ)
Duration
8-12 weeks
Dose Range
100 mcg of each
Frequency
Two to three times daily
Duration
8-12 weeks
Dose Range
100 mcg IV bolus
Frequency
Single dose
Duration
One-time test
Dosing information is for educational purposes only. Consult a healthcare professional before using any peptide.
Typical Vial Size
5 mg
Water Type
Bacteriostatic water (BAC water)
Mixing Volume
2 mL
Half-Life
~15-60 minutes
Molecular Weight
817.4 Da
Store reconstituted vial refrigerated at 2-8°C. Use within 30 days. Subcutaneous injection on an empty stomach; one dose ideally taken before bed to align with the natural overnight GH pulse.
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FDA Status
Not FDA approved for any indication.
Legal Status
Approved in Japan (Pralmorelin) as a GHD diagnostic. Unregulated research chemical in most other countries. Prohibited by WADA.
USA
Not approvedResearch-only; sold as a research chemical
EU
Not approvedNot authorized as medicinal product
UK
Not approvedClassified as research chemical
Japan
ApprovedPralmorelin (GHRP Kaken) approved 2006 as adult GH-deficiency diagnostic
Australia
Not approvedTGA has not authorized
Canada
Not approvedNot authorized for human use
Laferrere B, Abraham C, Russell CD, Bowers CY
Journal of Clinical Endocrinology & Metabolism (2005)
Demonstrated that GHRP-2 stimulates appetite in healthy adults but to a noticeably lesser degree than GHRP-6, supporting its preference in body-composition protocols.
View Study →Bowers CY, Granda R, Mohan S, Kuipers J, Baylink DJ, Veldhuis JD
Journal of Clinical Endocrinology & Metabolism (2004)
Showed that twice-daily subcutaneous GHRP-2 over 14 days produced sustained increases in GH pulse amplitude and IGF-1 without significant tachyphylaxis in healthy older adults.
View Study →Chihara K, Shimatsu A, Hizuka N, Tanaka T, Seino Y, Katofor Y
Journal of Clinical Endocrinology & Metabolism (2007)
Pivotal Japanese clinical trial supporting regulatory approval of Pralmorelin as a single-dose diagnostic test for adult GH deficiency, validating dosing and safety in a clinical population.
View Study →Selective growth hormone secretagogue with minimal side effects.
Long-acting growth hormone releasing hormone analog for sustained GH and IGF-1 elevation.
First-generation ghrelin mimetic — potent GH release with notable appetite stimulation.
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