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Compound monograph

Ipamorelin

Ipamorelin is a synthetic pentapeptide with a C-terminal amide, characterized in its original report as a growth hormone secretagogue acting through a GHRP-like receptor rather than the GHRH receptor.

Published: 2026-09-04Literature/identifier verification: 2026-08-23

01

Identity & nomenclature

Ipamorelin is a synthetic pentapeptide with a C-terminal amide, characterized in its original report as a growth hormone secretagogue acting through a GHRP-like receptor rather than the GHRH receptor.

Identified within a series of compounds lacking the central Ala-Trp dipeptide of growth hormone-releasing peptide-1. PubChem lists NNC 26-0161 as a development identifier.

Declared aliases and development codes: NNC 26-0161.

02

Molecular properties

Molecular formulaC38H49N9O5
Molecular mass711.9 Da
CAS Registry Number170851-70-4
PubChem CID9831659
UNIIY9M3S784Z6
Three-letter sequenceAib–His–D-2-Nal–D-Phe–Lys

Pentapeptide Aib-His-D-2-Nal-D-Phe-Lys-NH2. Contains alpha-aminoisobutyric acid, D-2-naphthylalanine, and D-phenylalanine, so a standard one-letter representation does not apply. The sequence is stated identically in the PubChem synonym record and in the original characterization paper.

03

Structural characteristics

Pharmacological profiling using GHRP and GHRH antagonists reported that ipamorelin acts via a GHRP-like receptor. The original report describes it as the first GHRP-receptor agonist whose selectivity for growth hormone release resembled that of GHRH, noting that plasma ACTH and cortisol were not raised significantly relative to GHRH stimulation even at doses more than 200-fold above the ED50 for growth hormone release, in contrast to GHRP-6 and GHRP-2. Structure-activity work on related analogs examined lysine mimetics combined with naphthyl- or biphenylalanine substitutions in the core.

  • Alpha-aminoisobutyric acid (Aib) at position 1
  • D-2-naphthylalanine at position 3
  • D-phenylalanine at position 4

Terminal features: C-terminal amide.

04

Molecular targets & mechanisms

05

Analytical considerations

Three of the five residues are non-proteinogenic, and the C-terminus is amidated. Identity methods must resolve the D-configuration residues and the amide, which a sequence-only assay assuming L-amino acids will not distinguish.

06

Verified bibliography

  1. Ipamorelin, the first selective growth hormone secretagogue.

    Raun K, Hansen BS, Johansen NL, Thøgersen H, Madsen K, Ankersen M, Andersen PH

    European journal of endocrinology · 1998-11 · Journal Article

    current
  2. Highly potent growth hormone secretagogues: hybrids of NN703 and ipamorelin.

    Hansen TK, Ankersen M, Raun K, Hansen BS

    Bioorganic & medicinal chemistry letters · 2001-07-23 · Journal Article

    current
  3. Ghrelin and glucose homeostasis.

    Delhanty PJ, van der Lely AJ

    Peptides · 2011-03-21 · Review

    current
  4. Growth hormone secretagogue receptor family members and ligands.

    Smith RG, Leonard R, Bailey AR, Palyha O, Feighner S, Tan C, Mckee KK, Pong SS, Griffin P, Howard A

    Endocrine · 2001-02 · Review

    current
  5. Structure of an antagonist-bound ghrelin receptor reveals possible ghrelin recognition mode.

    Shiimura Y, Horita S, Hamamoto A, Asada H, Hirata K, Tanaka M, Mori K, Uemura T, Kobayashi T, Iwata S, Kojima M

    Nature communications · 2020-08-19 · Journal Article

    current
  6. Determination of growth hormone releasing peptides (GHRP) and their major metabolites in human urine for doping controls by means of liquid chromatography mass spectrometry.

    Thomas A, Höppner S, Geyer H, Schänzer W, Petrou M, Kwiatkowska D, Pokrywka A, Thevis M

    Analytical and bioanalytical chemistry · 2011-02-06 · Journal Article

    current

10

Methodology & citation verification

Reference identity is checked against official PubMed metadata. Local deterministic receipts bind each normalized title and canonical metadata record to its verification date. Scientific values remain absent when an authoritative source has not been verified.

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