The short answer
Ipamorelin is a synthetic pentapeptide of roughly 712 Da containing non-standard residues and a C-terminal amide. Its most relevant analytical detail is that the free-acid form differs by only about 1 Da, so adequate mass-spectrometric resolution or chromatographic separation is needed to distinguish them on a certificate.
An unusual peptide by construction
Ipamorelin is a five-residue synthetic peptide first described in the late 1990s as a selective growth hormone secretagogue acting at the ghrelin receptor. Its interest in the literature was that it released growth hormone in preclinical models without the cortisol and ACTH elevation seen with earlier compounds in the class.
Structurally it is not a plain sequence of standard amino acids. It incorporates non-proteinogenic residues — aminoisobutyric acid and D-configured aromatic residues — and terminates in an amide rather than a free acid. Those features are deliberate, and they are also what make identity confirmation non-trivial.
Evidence remains overwhelmingly preclinical. Ipamorelin reached a completed industry Phase II trial for postoperative ileus, but it is not an approved drug in any jurisdiction, and material supplied for research is not a medicine.
The one-dalton problem
The C-terminus of ipamorelin should be an amide. The corresponding free acid — the product of deamidation — is a different compound that differs in mass by roughly one dalton. On a low-resolution instrument, or with poor chromatographic separation, the two are easy to confuse.
This matters because deamidation is a plausible degradation route rather than an exotic failure. A certificate that reports identity confirmed by a method with adequate resolution is making a stronger claim than one that reports a mass to the nearest whole number and moves on.
It is also a good test of a laboratory's rigour. A report that states the method, the instrument class and the specification is describing an experiment. A report that states only a number is describing a conclusion.
Reading an ipamorelin lot report
Confirm the reported mass is consistent with the amide form near 712 Da, and that identity was established by mass spectrometry or reference-standard comparison rather than assumed. Related growth hormone secretagogues — GHRP-2, GHRP-6, hexarelin — have entirely different masses, so a gross substitution is easy to catch once identity is actually tested.
Read purity as a method-bound figure: RP-HPLC area normalisation at a stated wavelength, against a stated specification. Then check net peptide content if reported, since salt counterion and residual water mean the powder's mass and its peptide mass are not the same number.
Complete the picture with the contamination controls — elemental impurities, bacterial endotoxin, sterility — and confirm the lot number matches the vial. USP ⟨1503⟩ describes the attribute set a synthetic peptide substance is expected to be characterised against.
The non-standard residues are worth a moment's thought when reading any of this. Aminoisobutyric acid and D-configured aromatic amino acids are not what a routine amino-acid analysis expects to find, and their presence is deliberate — they are what give the molecule its stability and receptor selectivity. For an analytical laboratory, that means identity work leans on mass and chromatographic behaviour rather than on standard sequencing assumptions. For a reader, it means a certificate that names its methods is telling you whether the laboratory handled an unusual molecule appropriately or ran a generic panel and reported the output.
Questions researchers ask
What molecular weight should ipamorelin show on a COA?
Approximately 712 Da for the free base in its correct C-terminal amide form. Because the deamidated free-acid impurity differs by only about one dalton, the useful question is not just the number reported but whether the method had the resolution to distinguish the two.
Is net peptide content the same as purity on an ipamorelin COA?
No. Purity is a chromatographic percentage describing how much of the peptide content is the target species. Net peptide content is a mass measurement describing how much of the powder is peptide at all, with the remainder being counterion and residual water. They answer different questions.
How is ipamorelin distinguished from other GHRPs?
By mass and sequence. GHRP-2, GHRP-6 and hexarelin are different peptides with different masses, so once identity is determined analytically rather than assumed, a substitution of that kind is immediately visible on a lot-specific certificate.
Is ipamorelin an approved medicine?
No. It has been studied in preclinical work and reached a completed Phase II trial, but it is not approved in any jurisdiction. Material supplied under this name is a research compound, not a pharmaceutical product, and is for laboratory use only.
At a glance
- Class
- Synthetic pentapeptide (5 residues), C-terminal amide
- Expected mass
- ≈ 712 Da (free base)
- Close impurity
- Free-acid (deamidated) form — differs by ≈ 1 Da
- Confused with
- GHRP-2, GHRP-6, hexarelin (all different masses)
- Status
- Research use only — not an approved medicine
How our Ipamorelin lots test
Applying the same standard described above to our own material. Each certificate below opens on the issuing laboratory's portal— not a PDF hosted here — so you are reading the lab's record, not ours.
Sources
Written from primary literature and published standards — never from other suppliers' marketing copy.
- PubChem CID 9831659 — Ipamorelin, formula, mass and sequence ↗
- Raun K et al., Eur J Endocrinol 1998 — Ipamorelin, the first selective growth hormone secretagogue ↗
- USP General Chapter ⟨1503⟩ Quality Attributes of Synthetic Peptide Drug Substances ↗
- Reference Standards to Support Quality of Synthetic Peptide Therapeutics (PMC) ↗
Written by Ivory Science. Scientific review: pending appointment of a named reviewer. Until then this page cites its sources directly so every claim can be checked at origin.
Related notes
For research use only. Not for human or veterinary use, ingestion or administration. Nothing here is medical advice, and no statement on this page has been evaluated by the FDA. Ipamorelin is not an approved medicine.