Ipamorelin explained: five residues, three unusual

Ipamorelin consists of five building blocks, three of which do not occur in the usual set of protein building blocks. That explains why it scores so well in the reports, and why one of the figures there is easy to misread.

Five building blocks, three of them synthetic

The sequence is Aib-His-D-2-Nal-D-Phe-Lys-NH₂. Only histidine and lysine are ordinary amino acids. Aib is aminoisobutyric acid, a building block with two methyl groups on the central carbon that stiffens the chain at that point. D-2-Nal and D-Phe are mirror-image forms; proteins almost exclusively contain the non-mirrored ones.

The NH₂ at the end stands for an amide at the chain terminus. It caps the free acid group and is part of the molecule; without it the molecular formula and mass would be different.

The molecular formula is C₃₈H₄₉N₉O₅, the molar mass 711.86 g/mol and the CAS number 170851-70-4. All of this is on the product page.

Why mirror-image building blocks are used at all

Enzymes that break chains down are tuned to the ordinary form. A mirror-image building block does not fit their binding site, so the chain is cleaved more slowly. SS-31 uses the same principle, with two mirror-image residues.

For manufacturing, this means the building blocks are more expensive but no harder to handle in solid-phase synthesis than ordinary ones. The shortness of the chain, four coupling steps, is the real reason for the high values in the reports.

Five reports, four of them from the smaller vial size

The certificate library holds five analytical reports for this substance. Four come from 5 mg lots and one from a 10 mg lot, the size sold here. The product page lists every certificate for the substance with the vial size of its lot; a report belongs to the lot it comes from, not to a different fill size.

What "100%" on a report means

The five reports give 98.91%, 99.37%, 99.644%, above 99.8% and 100%. That last figure needs explaining, because it promises more than a measurement can deliver.

Purity is derived from areas in the chromatogram: the area of the target signal divided by the total area of all signals. If the method finds no signal other than the target above its detection limit, the result is exactly one hundred. That means nothing was found, not that nothing is there. The report for this lot also carries a tolerance figure, which expresses exactly this point.

This shop states no blanket minimum purity; what counts is the measured value in the report for each lot. Purity should not be confused with peptide content: that describes what share of the weighed material is pure peptide, and it is regularly lower because of counterions and residual moisture.

Also as a ready-made blend

Together with CJC-1295 without DAC, ipamorelin is also in the catalogue as a ready-made blend, CJC-1295 no DAC + ipamorelin. The two belong to different classes; CJC-1295 no DAC explained covers the GHRH side.

For blends the specification applies per component. There is no shared purity figure for a blend. The library holds no report for the ipamorelin blend; its only blend report is for BPC-157 + TB-500, which gives no numerical purity figure. More on this in Research blends and their certificates.

In brief

Five building blocks with an amide end, three of them unusual, 711.86 g/mol, CAS 170851-70-4, five analytical reports, four from 5 mg lots and one from a 10 mg lot. How to check such reports yourself is covered in How to read a certificate of analysis.

Questions

What does "100%" mean in an analytical report?

That no signal other than the target signal was found above the detection limit of the method. It is a statement about the limit of the measurement, not about the absence of every impurity.

What is Aib?

Aminoisobutyric acid, a building block with two methyl groups on the central carbon. It does not occur in proteins and stiffens the chain at its position.

Why are most of the reports for 5 mg when the product is 10 mg?

Because a report belongs to the lot it comes from. Four of the five come from 5 mg lots and one from a 10 mg lot; the product page lists each with its vial size.