CJC-1295 No DAC: structure and analysis

What it is

CJC-1295 without DAC — also written as modified GRF(1-29) — is a synthetic analog of the first 29 amino acids of growth hormone-releasing hormone, carrying four amino acid substitutions and no drug-affinity complex.

The four substitutions are the point of the molecule: each replaces a residue at a site where the native sequence is vulnerable to enzymatic cleavage or chemical rearrangement, so the analog is more robust than the unmodified fragment.

The absence of the drug-affinity complex is what distinguishes this compound from the DAC-bearing version, and the two are frequently confused in this category.

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 distinguishes this compound from both native GHRH(1-29) and the DAC-bearing variant. The four substitutions shift the expected mass relative to the native fragment, and the absence of the drug-affinity complex shifts it substantially relative to the DAC form.

That second distinction is a large mass difference, which makes it an easy confirmation to perform and an unambiguous one to read — and therefore a poor thing for a supplier to leave undocumented.

Analytical considerations

At 29 residues this is a long synthetic peptide, so deletion and truncation sequences are the expected impurity class and chromatographic resolution of closely related species matters more than it does for a short chain.

Because three compounds in this catalogue are built on the GHRH sequence — this one, sermorelin and tesamorelin — the identity result is what establishes which of them is in a given vial. They are not interchangeable and their masses differ.

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.