GH axis research
Work on GHS-R1a-mediated signalling, where the pentapeptide structure and C-terminal amide are both part of what is being studied.
Peptide · Growth hormone axis
Ipamorelin (NNC 26-0161)
Five residues, three of them unnatural. On this molecule purity by HPLC is a weak claim — the question is whether the right diastereomer was made.
Also known as Ipamorelin · NNC 26-0161 · Ipam · Aib-His-D-2-Nal-D-Phe-Lys-NH₂
Sequence · 5 residues
BasicHydrophobicModified
- Residues
- 5
- Molecular weight
- 711.85
- Formula
- C38H49N9O5
- Purity
- 99.3% HPLC
Identity data as printed on the batch certificate of analysis.
Overview
What Ipamorelin is
Ipamorelin is a pentapeptide: Aib-His-D-2-Nal-D-Phe-Lys, amidated at the C-terminus, 711.85 g/mol. It is the smallest peptide in the growth-hormone range and chemically the least ordinary — three of its five residues are not the standard L-amino acids found in a protein.
That is the analytical point. Aib (α-aminoisobutyric acid) has no chiral centre; D-2-Nal and D-Phe are the opposite configuration to what a ribosomal synthesis would give. A reversed-phase HPLC method separates compounds by hydrophobicity, and a diastereomer — same sequence, one residue inverted — can elute within the main peak. Purity of 99.3% therefore says the material is chromatographically clean. It does not, by itself, say the stereochemistry is right.
What we can document is what the certificate carries: 99.3% purity, 0.6% total impurities, acetate at 15.8% and peptide content at 82.2% by nitrogen determination. The last two are the numbers that decide your weighing, and both are higher than buyers usually expect on a peptide this small.
- 99.3% by HPLC; total impurities 0.6%, largest single 0.3%
- Aib / D-2-Nal / D-Phe sequence, C-terminal amide — stated in full on the certificate
- Acetate 15.8% and peptide content 82.2%, reported as separate lines
- R&D code ES008 printed on the certificate, matching the catalogue
Identity
The record.
The identifiers your specification sheet, customs paperwork and product label all have to agree on. Where a number depends on the salt form, both are given.
- Chemical name
- Aib-His-D-2-Nal-D-Phe-Lys-NH₂ (C-terminal amide)
- Common name
- Ipamorelin; NNC 26-0161
- CAS number
- 170851-70-4
- Molecular formula
- C₃₈H₄₉N₉O₅
- Molecular weight
- 711.85 g/mol
- Residue count
- 5, of which two are D-configured and one is Aib
- Counter-ion
- Acetate — 15.8% on the current lot
- Appearance
- White or almost white powder
- Solubility
- Soluble in water
- Water content
- ≤ 8.0% (Karl Fischer)
- Peptide content
- 82.2% (nitrogen determination)
- Storage
- 2–8 °C, sealed, protected from light
HS codes are indicative only. Final classification is confirmed per shipment with your customs broker.
Manufacture
How it is made.
Short chain, unusual residues. The hard part is stereochemistry, not length.
- 01
Solid-phase assembly
Five residues couple quickly; the constraint is that three of them are non-standard. Aib and D-2-Nal have to be supplied as the correct building blocks, and D-Phe must not be substituted by its L form — a swap that changes nothing about the mass.
- 02
C-terminal amidation
The amide is part of the molecule. It is introduced at cleavage and confirmed by mass spectrometry; the free acid would be 1 Da lighter and a different product.
- 03
Purification
Reversed-phase HPLC at 220 nm. Because a diastereomer can co-elute, the certificate's impurity figures should be read as a purity statement rather than a stereochemical one.
- 04
Acetate exchange and drying
The peptide is converted to the acetate and lyophilised. Acetate is high on this molecule — 15.8% — which is why peptide content is 82.2% rather than the 90%+ seen on larger peptides.
Applications
Where it is used.
Supplied to laboratories studying the growth-hormone secretagogue class. Research use only.
Structure–activity work
The small size makes this a common model compound for testing how individual residue substitutions change receptor behaviour.
Analytical method development
A useful case for methods that must separate diastereomers, since a reversed-phase gradient alone will not resolve an inverted residue inside the main peak.
Specification
Release criteria.
The written limits we release against, with the method used to test each one. Batch results for the lot you receive are stated on its certificate of analysis.
| Parameter | Limit | Method |
|---|---|---|
| Appearance | White or almost white powder | Visual |
| Solubility | Soluble in water | Visual |
| Water content | ≤ 8.0% | Karl Fischer |
| Acetic acid | ≤ 18.0% | HPLC |
| Peptide content (N) | ≥ 80.0% | Nitrogen determination |
| Purity | ≥ 98.0% | HPLC |
| Total impurities | ≤ 2.0% | HPLC |
| Largest single impurity | ≤ 1.0% | HPLC |
| Dichloromethane residue | ≤ 0.060% | GC |
| DMF residue | ≤ 0.088% | GC |
| Bacterial endotoxin | < 10 EU/mg | LAL |
| Total aerobic count | ≤ 100 cfu/g | Plate count |
| Mould & yeast | ≤ 100 cfu/g | Plate count |
| Shelf life | 24 months from manufacture | Stability programme |
Tighter limits — for example a lower heavy-metal ceiling or a residual-solvent panel — can be quoted against your own specification wording.
HPLC · ES008
Certificate
Reading the certificate.
Five residues is short enough that the certificate has to carry more of the identity work.
Check that the sequence names the D residues
A certificate listing “Aib-His-Nal-Phe-Lys” without configuration has dropped the most important information on the page. The D forms are the molecule; the all-L version is a different compound with the same mass and a different receptor profile.
Acetate at 15.8% is high, and it is fine
The limit is ≤ 18%. A high counter-ion load lowers peptide content to 82.2%, which is the number to use when weighing. Do not calculate concentrations from the label weight on this material.
Mass spectrometry confirms mass, not configuration
An ESI result matching 711.85 proves the composition. It cannot distinguish D from L. If stereochemistry is critical to your work, ask what chiral or diastereomer-selective data exists for the batch.
Documentation & packaging
What ships with it.
The paperwork travels with the goods. If your QA team needs an extra declaration, ask before the order is released — some are issued per production lot and cannot be retrofitted.
Certificate of analysis
Purity, impurities, acetate, water, peptide content and microbiological results for the lot.
Identity data
Mass spectrometry against the theoretical 711.85, plus the full sequence with configuration.
SDS & specification
Safety data sheet and the enterprise standard the batch is released against.
Batch traceability
Lot number, manufacture date and retest date; the file travels with the shipment.
| Pack size | Presentation | Typical use |
|---|---|---|
| 1–10 g | Amber vial, 10 mL | Evaluation |
| 25–50 g | Amber vial, 50 mL | Pilot scale |
| 100 g | Amber vial, 100 mL | Small commercial |
| 1 kg+ | Foil bag, quoted per order | Bulk |
Questions
Before you order.
The questions buyers actually ask about Ipamorelin. Anything not covered here, ask directly — you will get an answer from someone technical, not a template.
Why is the peptide content only 82.2%?
Because acetate accounts for 15.8% of the powder and water for another 4.8%. Nitrogen determination gives the peptide fraction, which is 82.2%. It is a normal figure for an acetate salt of a small, highly charged peptide.
Should I weigh against purity or peptide content?
Peptide content. Purity describes how clean the peptide is; peptide content describes how much of the powder is peptide at all. On this material the gap is about 17 percentage points.
What makes ipamorelin chemically unusual?
Three of its five residues are non-standard: Aib has no chiral centre, and D-2-Nal and D-Phe are the opposite configuration to a ribosomal product. That is why the sequence on the certificate must state configuration, not just residue names.
Is this the same as GHRP-2 or GHRP-6?
No. They belong to the same secretagogue family but are different molecules with different sequences, masses and CAS numbers. Ipamorelin is the pentapeptide at 711.85 g/mol, CAS 170851-70-4.
How should it be stored?
2–8 °C, sealed and protected from light. This one is refrigerated rather than frozen — follow the certificate rather than a generic assumption about peptides.
Can you supply a batch with lower acetate?
Ask. Reducing the acetate load requires a different salt-exchange endpoint and would be a made-to-order batch. Tell us the peptide-content target and we will quote against it.
Related
Often quoted together.
Quotation
Ask for Ipamorelin, by the gram.
Send the quantity, the grade you need and the destination. You will get a written quotation with lead time, packaging options and the documentation set for this material.