What Is GHRP-2 (Pralmorelin)? Structure and Status

GHRP-2 is a synthetic six-residue peptide, D-Ala-D-2Nal-Ala-Trp-D-Phe-Lys-NH2, that acts on the growth hormone secretagogue receptor, also called the ghrelin receptor. Its nonproprietary name is pralmorelin. Its formula is C45H55N9O6, its molecular weight about 818.0 Da and its CAS number 158861-67-7.

How does it relate to GHRP-6?

GHRP-2 belongs to the growth hormone-releasing peptide family that began with GHRP-6, described in 1984. It replaces the first two residues of GHRP-6 with D-alanine and D-2-naphthylalanine. Like GHRP-6, it was reported in animal and human pharmacology to raise adrenocorticotropic hormone and cortisol as well as growth hormone, unlike the later, more selective Ipamorelin.

Where has it been used?

Pralmorelin has been used in Japan as a diagnostic agent for assessing growth hormone secretion, and studies from that setting describe growth hormone responses to it [1]. It is not approved as a medicine in the United States. As of April 2026 it is on the FDA list of bulk drug substances that may present significant safety risks in compounding [3]. It is also a target of anti-doping analysis, and methods for detecting it and its metabolite in urine have been published [2].

How is it identified in the laboratory?

Its tryptophan and naphthylalanine residues absorb ultraviolet light strongly, which makes HPLC detection straightforward, and mass spectrometry confirms the mass. Three of its six residues are D-amino acids, which have the same mass as their L-forms, so stereochemical purity requires a chiral method.

Frequently asked questions

Is GHRP-2 the same as Ipamorelin?

No. Ipamorelin is a five-residue peptide with a different sequence and a molecular weight of about 711.9 Da.

Is pralmorelin a peptide or a small molecule?

It is a peptide, although several of its residues are non-standard amino acids.

Does FLASK list GHRP-2?

Yes, as GHRP-2 10 mg, with structure data on the product page.