Sermorelin: structure and analysis

What it is

Sermorelin is the first 29 amino acids of growth hormone-releasing hormone, produced synthetically as the C-terminal amide. It is the native fragment rather than an analog: no substitutions, no acyl modification, no drug-affinity complex.

Growth hormone-releasing hormone is a 44-residue peptide, and the 1-29 fragment retains the activity of the full sequence — which is why three compounds in this catalogue are built on it.

The C-terminal amide is the one deliberate departure from the plain fragment, and it is a structural feature rather than an incidental one.

How it is produced

Assembled by solid-phase peptide synthesis: the chain is built one residue at a time on an insoluble resin support, then cleaved from the resin, deprotected and purified — most commonly by reversed-phase high-performance liquid chromatography. The purified material is lyophilized to a dry solid.

The impurity profile that appears on a certificate is a record of where that process was imperfect: deletion sequences from an incomplete coupling, truncated chains, and species retaining a protecting group.

Confirming identity

Mass spectrometry confirms the 29-residue chain and the C-terminal amide. The amide and the corresponding free acid differ by approximately one mass unit, so distinguishing them requires high-resolution measurement — and they are different compounds.

Because this is the unmodified fragment, its mass also distinguishes it from CJC-1295 without DAC, which is the same fragment carrying four substitutions.

Analytical considerations

Twenty-nine residues means twenty-nine coupling steps, and the probability of at least one incomplete coupling rises with chain length. Deletion sequences differing from the target by a single residue are the expected impurity class, and they are closely spaced chromatographically.

Incomplete C-terminal amidation is the other characteristic impurity, and the small mass shift involved makes it a result that depends on the resolution of the identity method.

With three GHRH-derived compounds in this catalogue, the identity result is what establishes which is in a given vial. Their masses differ and they are not interchangeable.

What its certificate reports

A certificate for a lot of this material names the lot, names the issuing laboratory, and states for each parameter both the method used and the specification the result was measured against. Identity and purity are the two core results; net peptide content states how much of the fill weight is actually peptide.

A certificate belongs to a lot, not to a product line. When a new lot is released it is tested again, and the certificate published against it is that lot's certificate — a previous lot's result is never carried forward.

Research use only

This page describes structure and analysis. It makes no claim about what this compound does, and none should be inferred from it. Material is supplied for laboratory research use only: it is not a drug, food, dietary supplement, cosmetic or medical device, it is not for human or veterinary consumption, and no dosing, administration or reconstitution guidance is provided for any such use.