Ipamorelin

Pentapeptide · GHSR-1a agonist (ghrelin mimetic)

Identifier graph

Cross-references to canonical chemistry knowledge graphs. Each binding is the same identity used in PubMed-indexed literature.

CAS Registry Number
170851-70-4 · CAS Common Chemistry
Wikidata
Q20707829
ChEMBL
CHEMBL58547
Molecular formula
C38H49N9O5
Molecular weight
711.86 g/mol
Peptide sequence
Aib-His-D-2-Nal-D-Phe-Lys-NH2

What is Ipamorelin?

Ipamorelin is a synthetic pentapeptide with the sequence Aib-His-D-2-Nal-D-Phe-Lys-NH₂, where Aib is the unnatural amino acid α-aminoisobutyric acid and the C-terminus is amidated to improve metabolic stability. The compound binds and activates the growth hormone secretagogue receptor type 1a (GHSR-1a), the same receptor activated by endogenous ghrelin.

CAS Registry Number 170851-70-4, molecular formula C₃₈H₄₉N₉O₅, molecular weight 711.86 g/mol. Originally developed by Novo Nordisk as research code NNC 26-0161, Ipamorelin progressed to phase II clinical investigation before being discontinued; it remains widely used as a research-grade GH-secretagogue reference compound.

Mechanism of action

Ipamorelin selectively binds the GHSR-1a receptor on pituitary somatotrophs and stimulates pulsatile growth-hormone release. Unlike earlier-generation growth-hormone-releasing peptides (e.g. GHRP-2, GHRP-6), Ipamorelin shows minimal effect on cortisol, prolactin or aldosterone secretion in published studies — a selectivity attributed to the Aib-containing N-terminus and the D-amino-acid substitutions that restrict conformational sampling at off-target receptors.

The compound is rapidly absorbed following subcutaneous administration and has a published plasma half-life of approximately 2 hours.

Research context

Investigated in preclinical models of growth-hormone secretion, bone-density changes during prolonged immobilisation, and post-surgical recovery. Ipamorelin reached phase II clinical trial for post-operative ileus before development was discontinued.

Researchers often combine Ipamorelin with the GHRH analogue CJC-1295 (No DAC) in protocols that probe the synergistic GHRH+GHSR-1a signalling pathways. NMChem supplies both compounds as a 5 mg + 5 mg blend (CJC/Ipa) for these protocols.

Analytical specifications

Every batch of Ipamorelin supplied by NMChem is characterised by reversed-phase HPLC for purity determination and by mass spectrometry for identity confirmation. Certificate of Analysis (COA) documents are issued per batch and made available on request.

Identity is confirmed by electrospray-ionisation mass spectrometry (ESI-MS); the observed mass falls within ±2 Da of the theoretical monoisotopic mass calculated from the residue sequence. Purity is determined by reversed-phase HPLC on a C18 column with a trifluoroacetic-acid-modified water/acetonitrile gradient and reported as the area-under-curve percentage of the main peak at 214 nm. NMChem specification is ≥99% main peak. Material ships as lyophilised powder and must be reconstituted in sterile water or bacteriostatic water immediately before use.

Browse the COA database

UK regulatory status

Supplied as a research-grade reference standard for laboratory use only. Not a licensed medicinal product in the United Kingdom and not approved by the MHRA for human or veterinary administration. Sale is restricted to researchers, institutions and laboratory professionals; the compound must be retained within research premises. End-user compliance with the Human Medicines Regulations 2012, the Misuse of Drugs Act 1971 (where applicable) and local institutional biosafety policy is the responsibility of the buyer.

Research literature

Selected peer-reviewed publications from PubMed referencing this compound.

  1. Therapeutic Peptides in Orthopaedics: Applications, Challenges, and Future Directions. Rahman OF et al. · Journal of the American Academy of Orthopaedic Surgeons. Global research & reviews · 2026
    PubMed PMID 41490200
  2. Injectable Peptide Therapy: A Primer for Orthopaedic and Sports Medicine Physicians. Mayfield CK et al. · The American journal of sports medicine · 2026
    PubMed PMID 41476424
  3. Ipamorelin, the first selective growth hormone secretagogue. Raun K et al. · European journal of endocrinology · 1998
    PubMed PMID 9849822

Related compounds

Other research compounds in adjacent mechanism classes or commonly used alongside Ipamorelin.

  • GHRP-2
    Pentapeptide · GHSR-1a agonist (ghrelin mimetic)
  • CJC-1295 (No DAC)
    GHRH (1-29) analogue · 29-residue peptide
  • Tesamorelin
    GHRH(1-44) analogue with N-terminal fatty acid · 44-residue peptide
  • AOD-9604
    HGH (176-191) lipolytic fragment · 16-residue peptide

Frequently asked questions about Ipamorelin

What is the difference between Ipamorelin and GHRP-2?
Both are pentapeptide GHSR-1a agonists. Ipamorelin (Aib-His-D-2-Nal-D-Phe-Lys-NH₂) is selectively pulsatile for GH release with minimal cortisol or prolactin elevation. GHRP-2 is structurally distinct, more potent at GHSR-1a but with documented cortisol-elevating activity in published studies. Selection depends on whether the research endpoint requires selectivity (Ipamorelin) or potency (GHRP-2).
Why is Ipamorelin often paired with CJC-1295?
CJC-1295 is a GHRH analogue (it activates the growth-hormone-releasing-hormone receptor); Ipamorelin is a GHSR-1a agonist (ghrelin receptor). The two receptors are mechanistically distinct and synergistic — published research suggests co-administration produces greater GH release than either compound alone. This is why the two are commonly co-supplied as a blend.
Is Ipamorelin approved for human therapeutic use?
No. Ipamorelin did not progress beyond phase II clinical trial and is not licensed as a medicinal product in any jurisdiction. It is supplied as a research-grade reference standard for laboratory use only.

Get research-grade Ipamorelin from NMChem

UK supplier · HPLC and MS verified · Per-batch Certificate of Analysis · Tracked Royal Mail dispatch.

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