GHRP-2 5mg

What is GHRP-2 ?

GHRP-2, also written GHRP2, is a synthetic six-amino-acid peptide that activates the ghrelin receptor, GHS-R1a. In the clinical literature it is called pralmorelin, development code KP-102. Each GHRP-2 5mg vial holds white lyophilised powder.

Its first two residues are D-alanine and D-2-naphthylalanine, an unnatural aromatic amino acid. These D-residues protect the chain from aminopeptidase cleavage. The rest of the sequence, Ala-Trp-D-Phe-Lys-NH₂, is shared with GHRP-6.

As pralmorelin, GHRP-2 has been used in Japan as a diagnostic agent when assessing growth hormone deficiency. It holds no marketing authorisation in the UK.

GHRP-2 Research Applications

• Receptor pharmacology : a reference GHS-R1a agonist in receptor-expression and secretagogue assay systems.
• Appetite research : seven healthy men ate about 36% more at a buffet meal with GHRP-2 than with saline. Serum growth hormone rose as expected (Laferrère et al., J Clin Endocrinol Metab, 2005).
• Diagnostic pharmacology : the pralmorelin literature on testing growth hormone reserve.

Laferrère and colleagues called GHRP-2 a valuable tool for studying ghrelin effects on eating behaviour. Beyond the appetite and diagnostic work, controlled human data are sparse. GHRP-2 is not an approved therapeutic agent in any jurisdiction.

GHRP-2 vs GHRP-6

Both are hexapeptides that act on GHS-R1a, and they differ only at positions 1 and 2. GHRP-6, the original Bowers compound, starts His-D-Trp. GHRP-2 starts D-Ala-D-2-Nal. Molecular weight tells them apart: 818.0 g/mol for GHRP-2 and 873.0 g/mol for GHRP-6. The hunger effect is often linked to GHRP-6, yet the controlled human food-intake study in this class used GHRP-2.

Research Overview

GHRP-2, also written GHRP2 or GHRP 2 and known in the clinical literature as pralmorelin (development code KP-102), is a synthetic hexapeptide growth hormone secretagogue with the sequence D-Ala-D-2-Nal-Ala-Trp-D-Phe-Lys-NH₂, molecular formula C₄₅H₅₅N₉O₆, molecular weight 817.9 g/mol and CAS number 158861-67-7. The design logic is visible in the sequence: D-alanine at position 1 and the unnatural aromatic D-2-naphthylalanine at position 2 protect the backbone from aminopeptidase cleavage while presenting the aromatic pharmacophore the receptor recognises, and the C-terminal lysine amide completes a motif shared across the growth hormone releasing peptide family. That receptor is GHS-R1a, the growth hormone secretagogue receptor, and its identification is a textbook example of reverse pharmacology, Howard and colleagues (Science, 1996) cloned the orphan G-protein-coupled receptor from pituitary and hypothalamus using peptides of exactly this class as the pharmacological probe, three years before ghrelin was identified as the endogenous ligand. GHRP-2 is therefore accurately described as a ghrelin-receptor agonist that predates the discovery of ghrelin itself. Human pharmacology exists but is narrow. Laferrère and colleagues (J Clin Endocrinol Metab, 2005) reported that GHRP-2 infusion increased ad libitum food intake in healthy young men in a dose-dependent manner, behaving like ghrelin, which established the peptide as a standard pharmacological tool in ghrelin-pathway appetite research. Separately, pralmorelin has been used in Japan as a diagnostic agent in the assessment of growth hormone deficiency, a regulatory history that distinguishes it from most compounds in this class. It should be stated plainly that GHRP-2 holds no marketing authorisation from the MHRA or any other regulator as a therapeutic product, and the wider claims attached to the GHRP family online run far ahead of the controlled findings summarised here. This vial contains 5mg of GHRP-2 as a white lyophilised powder, batch UKPL-781 at 99.8% purity by RP-HPLC with the certificate of analysis published on this page, supplied strictly for in-vitro laboratory research use only.

Storage and Reconstitution

Keep sealed vials at -20°C, away from light and moisture. After reconstitution, keep the solution at 2-8°C and use it within 4 weeks, or freeze single-use aliquots at -20°C. The tryptophan at position 4 is the residue most prone to oxidation, so keep solutions away from light.

Vials are sold on their own, without bacteriostatic water for mixing or other supplies.

How to reconstitute and handle

Bring the vial to room temperature and swab both stoppers with alcohol. Run bacteriostatic water slowly down the inside wall of the vial, then swirl until the powder dissolves. Do not shake or vortex. GHRP-2 dissolves readily and gives a clear, colourless solution. Do not use a vial that stays cloudy or shows particles. Label it with the reconstitution date.

• Aliquot reconstituted stock into single-use volumes and avoid repeated freeze-thaw cycles. The tryptophan residue at position 4 is the oxidation-prone site, so keep stored solutions light-protected and label each aliquot with the reconstitution date.

For the full method, see the peptide reconstitution guide and the reconstitution calculator.

Research References

• Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men (Laferrère et al., J Clin Endocrinol Metab, 2005)
• A receptor in pituitary and hypothalamus that functions in growth hormone release (Howard et al., Science, 1996)

Published research on GHRP-2 is indexed on PubMed. See our full UK buyer's guide for GHRP-2.