Why is ipamorelin's sequence written with full residue names?

Single-letter codes cover only the twenty standard L-amino acids. Ipamorelin contains Aib and two D-residues, none of which the code can express.

D-2-naphthylalanine, a phenylalanine analogue carrying a naphthalene ring instead of a benzene, in the D configuration.

Is ipamorelin's identity confused like CJC-1295's?

No. One CAS, one CID, one compound, with mass, formula and sequence all in agreement.

Ipamorelin Sequence and Chemical Identity

The short answer

Ipamorelin is Aib-His-D-2-Nal-D-Phe-Lys-NH2 with CAS 170851-70-4, PubChem CID 9831659, UNII Y9M3S784Z6 and molecular weight 711.9 Da for formula C38H49N9O5. Its identifiers are unambiguous, which is unusual in this field and stands in sharp contrast to CJC-1295, where one name covers two different molecules depending on whether DAC is present.

Key facts

Sequence: Aib-His-D-2-Nal-D-Phe-Lys-NH2
CAS: 170851-70-4
PubChem CID: 9831659
UNII: Y9M3S784Z6
Molecular weight: 711.9 Da
Formula: C38H49N9O5
Development code: NNC 26-0161

Reading the sequence notation

Aib is α-aminoisobutyric acid, not one of the twenty standard amino acids and therefore written out rather than given a letter. D-2-Nal is D-2-naphthylalanine, a phenylalanine analogue with a naphthalene ring in place of the benzene. D-Phe is D-phenylalanine. The NH2 at the end denotes a C-terminal amide rather than a free carboxyl.

Why it cannot be written in single-letter code

Single-letter codes exist only for the twenty proteinogenic L-amino acids. Ipamorelin contains a non-proteinogenic residue and two D-isomers, none of which the code can express. This is itself informative: a peptide that cannot be written as a simple letter string is a designed molecule rather than a natural fragment.

Research material referenced

CJC-1295 + Ipamorelin 5+5mg, third-party HPLC tested

Buy CJC-1295 + Ipamorelin · £36.99

A clean identity, by contrast

CAS 170851-70-4 resolves to CID 9831659, and the mass, formula and sequence agree. There is no second compound sharing the name, no contradictory synonym set, no unresolvable registry number. Compared with CJC-1295 in the same category (or TB-500 and GHK-Cu elsewhere in this library), ipamorelin is unusually straightforward.

The development code

NNC 26-0161 is Novo Nordisk's internal designation, and it appears in the older literature. Searching for it surfaces records the name ipamorelin misses, which is the same pattern as PL-14736 for BPC-157 and thymosin beta-4 for TB-500.

Analytical confirmation

Mass spectrometry against 711.9 Da. The peptide contains no cysteine and no methionine, so neither disulfide species nor a +16 Da oxidation satellite should appear. At five residues the synthesis is short, though the non-standard residues are more expensive and less routine to couple than ordinary amino acids.

Frequently asked questions

Why is ipamorelin's sequence written with full residue names?: Single-letter codes cover only the twenty standard L-amino acids. Ipamorelin contains Aib and two D-residues, none of which the code can express.
What is D-2-Nal?: D-2-naphthylalanine, a phenylalanine analogue carrying a naphthalene ring instead of a benzene, in the D configuration.
Is ipamorelin's identity confused like CJC-1295's?: No. One CAS, one CID, one compound, with mass, formula and sequence all in agreement.

Extended research context

The CJC-1295 & Ipamorelin deep dive

Deep dive: why CJC-1295 and Ipamorelin are studied together

CJC-1295 is a modified GHRH (growth-hormone-releasing hormone) analogue; Ipamorelin is a selective growth-hormone secretagogue that binds the ghrelin receptor (GHS-R1a). In pituitary-cell research models the two act on independent pathways whose downstream effect converges on GH release. CJC-1295 amplifies the endogenous GHRH signal while Ipamorelin adds a separate ghrelin-pathway stimulus. That's why supplier catalogues frequently package them together as a research reference blend.

DAC vs no-DAC: which CJC-1295 is which

'CJC-1295 with DAC' contains a Drug Affinity Complex (a Lys-maleimide moiety) that binds serum albumin and extends half-life to several days. 'CJC-1295 no-DAC' (also called Modified GRF 1-29) lacks the linker and clears in minutes. These are pharmacologically different peptides. A CoA must specify which form is in the vial; mass differs (~3,367 Da with DAC vs ~3,367 minus linker for no-DAC).

Ipamorelin's selectivity profile

Unlike earlier GHS-R agonists (e.g. GHRP-6), Ipamorelin was engineered for minimal cross-activity at cortisol- and prolactin-releasing pathways in research models. That receptor selectivity is why it is the reference secretagogue for controlled pituitary-cell studies.

Research applications

▸Pituitary-cell GH-release assays (comparator vs GHRH and hexarelin)
▸Half-life comparison studies: DAC vs no-DAC CJC-1295 forms
▸Ghrelin-receptor binding assays for Ipamorelin analogue development
▸Analytical HPLC method development for lipidated GHRH analogues
▸Stability testing under refrigerated storage

Handling checklist

✓Store lyophilised at −20 °C long-term
✓Reconstitute in bacteriostatic water; both peptides dissolve readily
✓Aliquot immediately, refrigerate at 2–8 °C, use within 28 days
✓Confirm salt form and DAC/no-DAC status on CoA before starting a study
✓Do not use for human administration (research reference only)

Common research-handling mistakes

Learnt from thousands of researcher orders across our UK labs.

✗ Confusing DAC and no-DAC CJC-1295

Fix: Check the CoA. The two have very different pharmacokinetics.

✗ Assuming Ipamorelin acts on GHRH receptors

Fix: It binds the ghrelin receptor (GHS-R1a), a separate pathway from CJC-1295.

✗ Storing reconstituted solution at room temperature

Fix: Refrigerate 2–8 °C after reconstitution.

Continue researching

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Primary sources & clinical trials

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The UK Peptides Editorial Team · Research library, UK Peptides

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