Ipamorelin research peptide UK: a selective GHS-R ligand for the laboratory
Ipamorelin (NNC 26-0161) for UK researchers: its Aib and D-amino-acid chemistry, receptor pharmacology literature, solubility.
Ipamorelin is a synthetic pentapeptide developed in the 1990s as a selective ligand for the growth hormone secretagogue receptor (GHS-R1a, the ghrelin receptor). It is a well-characterised research compound with a clear pharmacological literature, unusual chemistry for a peptide, and a specific set of handling considerations. This guide covers what it is, its chemistry, where it appears in the literature, how to store and reconstitute it, and how Alphex Ipamorelin is verified. All material is supplied for laboratory and in-vitro research only.
What Ipamorelin is
Ipamorelin (development code NNC 26-0161) is a five-residue peptide with the sequence Aib-His-D-2-Nal-D-Phe-Lys-NH2. Three features make it chemically distinctive: it contains the non-proteinogenic residue alpha-aminoisobutyric acid (Aib) at the N-terminus, it contains two D-amino acids (D-2-naphthylalanine and D-phenylalanine), and it is C-terminally amidated. These modifications were introduced during its design to improve receptor selectivity and resistance to enzymatic breakdown, and they mean the peptide is not something a cell would produce naturally.
It belongs to the family of growth hormone secretagogues alongside GHRP-2, GHRP-6 and hexarelin, and the original research interest was in its selectivity: unlike earlier compounds in the family it was reported to have little effect on other pituitary hormones in the assay systems used. It has no marketing authorisation as a medicine anywhere.
Specification
- Sequence: Aib-His-D-2-Nal-D-Phe-Lys-NH2
- Molecular formula: C38H49N9O5
- Molecular weight: 711.9 g/mol
- CAS number: 170851-70-4
- Synonym: NNC 26-0161
- Form supplied: lyophilised powder in a vacuum-sealed glass vial, acetate salt
- Purity specification: 99+% by RP-HPLC at 220 nm; identity by ESI-MS within 1 Da of theoretical mass
- Sizes: 5 mg and 10 mg vials
Where Ipamorelin appears in the research literature
Ipamorelin's literature is more pharmacological than most research peptides, because it was designed as a receptor ligand rather than isolated from a natural source. Themes include:
- Receptor pharmacology. Binding and functional assays at GHS-R1a, comparisons of potency and selectivity against GHRP-6 and related secretagogues, and structure-activity work explaining the role of the D-amino acids and Aib.
- Pituitary cell and animal models. The original characterisation work in cultured pituitary cells and in rodent, swine and other animal models.
- Gastrointestinal motility models. A later strand of preclinical work looked at ghrelin-receptor agonists, including Ipamorelin, in models of post-operative ileus; a clinical development programme in that indication was discontinued.
- Peptide chemistry. Its stability and analytical behaviour, which is relevant to anyone developing HPLC methods for it because the naphthylalanine residue gives it a strong UV signature and a later retention time than most small peptides.
The presence of D-amino acids and Aib means Ipamorelin is resistant to many proteases, which is worth noting when designing degradation controls. Nothing in this literature establishes any use outside the laboratory.
Handling, storage and reconstitution
Lyophilised: -20 C long term, 2-8 C short term, protected from light and moisture. Warm the sealed vial to room temperature before opening.
Reconstitution: Ipamorelin is soluble in water at typical working concentrations, though the two aromatic D-residues make it less hydrophilic than peptides such as BPC-157; if a high-concentration stock is slow to dissolve, gentle swirling and a few minutes at room temperature usually resolves it, and a small proportion of DMSO or acetic acid can be used where the assay allows. Reconstitute in bacteriostatic water for multi-sample stocks or sterile water or buffer for single use, adding solvent down the vial wall without shaking.
In solution: refrigerate at 2-8 C in the dark and use within a few weeks; aliquot and freeze at -20 C for longer storage; avoid repeated freeze-thaw. Aromatic residues make the peptide somewhat prone to adsorbing onto plastic surfaces at very low concentrations, so use low-binding tubes or include carrier protein for dilute working solutions if your assay is sensitive to it. See storage, reconstitution and shelf life.
How Alphex verifies Ipamorelin
Every batch is synthesised to the Aib-His-D-2-Nal-D-Phe-Lys-NH2 sequence, run on reverse-phase HPLC at 220 nm against a reference standard with a 99+% area purity threshold. The results are issued on a Certificate of Analysis carrying the batch number on the vial, with the chromatogram and the testing laboratory named. UK stock, same-day dispatch before 2pm Monday to Friday. Method: how Alphex tests every batch.
Because Ipamorelin contains D-amino acids, identity by mass alone cannot distinguish it from an all-L stereoisomer of the same sequence; the synthesis route and the reference standard used for HPLC are what guarantee the correct stereochemistry. This is one reason a named, independent laboratory and a reference-standard comparison matter more for this compound than a bare purity figure.
Buying Ipamorelin in the UK
Ipamorelin is widely sold and widely mislabelled. Check the COA for the correct mass (711.9), an HPLC threshold and chromatogram, and a named laboratory, and run the 12-point supplier checklist before ordering from anyone. Our comparison of UK supplier types is in where to buy research peptides in the UK.
Frequently asked questions
Why is it listed as "Ipamorelin (laboratory reagent)"?
Because that is what it is supplied as. The listing name reflects the research-use-only status of every product in the catalogue.
Is Ipamorelin the same as GHRP-6 or CJC-1295?
No. GHRP-6 is a different secretagogue with a different sequence; CJC-1295 is a modified GHRH analogue acting at a different receptor entirely. They are sometimes discussed together but are chemically and pharmacologically distinct compounds.
Can I request the COA before ordering?
Yes: request the in-stock batch COA.
Is Ipamorelin legal to buy in the UK for research?
Yes. It is not a controlled substance and can be purchased and possessed for laboratory research; it has no marketing authorisation as a medicine. See UK research peptide compliance.
Sources and further reading
- Kojima M et al. Ghrelin is a growth-hormone-releasing acylated peptide from stomach. Nature 1999: identification of the endogenous GHS-R ligand
Alphex Ipamorelin is supplied for laboratory and in-vitro research by qualified researchers only. It is not authorised for human or veterinary use.
Research use only. Alphex products are supplied exclusively for laboratory and in-vitro research by qualified researchers. They are not authorised for human or veterinary use, and nothing in this note is advice on any such use.
Published 23 February 2026, last reviewed 16 August 2026. Alphex reviews research notes when the testing method, the catalogue or UK guidance changes.