What CJC-1295 is
CJC-1295 without DAC — more precisely, Modified GRF (1-29) — is a 29-amino-acid analogue of growth hormone-releasing hormone. Native GHRH is a 44-residue peptide, but its receptor-activating activity resides in the first 29 residues, so GHRH (1-29) is the functional fragment that analogue development starts from.
Four substitutions distinguish the modified form from the native fragment:
| Position | Substitution | Purpose |
|---|---|---|
| 2 | D-Ala | Blocks DPP-4 cleavage, the primary degradation route |
| 8 | Gln | Prevents asparagine deamidation during storage |
| 15 | Ala | Improves bioactivity |
| 27 | Leu | Prevents methionine oxidation |
Two of the four are stability modifications aimed at the molecule sitting in a vial rather than at its behaviour in a receptor assay — asparagine deamidation and methionine oxidation are both classic degradation pathways in stored peptides.
With and without DAC
The name CJC-1295 is used for two distinct molecules, and the distinction is pharmacologically fundamental rather than cosmetic.
Without DAC (Modified GRF 1-29, ~3,368 Da) has a short half-life and produces a brief pulse of receptor activation resembling the endogenous pattern.
With DAC (~3,647 Da) carries a maleimidoproprionic acid group that forms a covalent bond with serum albumin, extending circulating half-life from minutes to days and producing sustained rather than pulsatile receptor exposure.
That is not a subtle formulation difference — pulsatile versus continuous GHRH receptor signalling is a well-recognised distinction in the endocrine literature, and research designs generally depend on which one is being used. The masses differ by roughly 280 Da, so mass spectrometry resolves the question unambiguously. This page describes the non-DAC form.
Molecular profile
| Property | Value |
|---|---|
| Also known as | Modified GRF (1-29), CJC-1295 no-DAC |
| Length | 29 amino acids |
| Molecular weight | ~3,368 Da |
| Receptor target | GHRH receptor |
| Appearance | White lyophilised powder |
Research context
CJC-1295 is used in growth hormone axis research as a GHRH receptor agonist — receptor binding and selectivity work, cAMP accumulation as a functional readout in pituitary cell models, and comparative studies examining pulsatile versus sustained receptor stimulation. It appears frequently alongside growth hormone secretagogue receptor agonists such as ipamorelin, since the two act on separate receptors within the same axis.
Supplied for in-vitro laboratory research only. No therapeutic claim is made and no dosing or administration guidance is provided.
Analytical notes
The with-DAC / without-DAC ambiguity makes mass confirmation the load-bearing test for this compound. The two forms are close enough in behaviour on reversed-phase chromatography that a purity figure alone will not tell you which you have, and far enough apart in mass that any real MS result will.
On the purity side, the substitutions at positions 8 and 27 exist specifically to close off deamidation and oxidation pathways, which means that finding deamidated or oxidised species in the impurity profile points at a manufacturing or storage failure rather than at an inherent property of the molecule. Those species elute close to the main peak, so the chromatogram matters more than the integrated percentage.
Handling and storage
Store sealed at −20 °C, protected from light and moisture, and bring to room temperature before opening. Reconstitute by running diluent down the vial wall and swirling. Store solution at 2–8 °C, protected from light, and avoid repeated freeze-thaw.
What we supply
Modified GRF (1-29) released against a ≥99% purity specification, with HPLC purity and mass spectrometry identity confirmation on every batch and a batch-specific Certificate of Analysis on which the observed mass — and therefore which form of the molecule you have — is stated explicitly. Select batches additionally receive independent third-party purity verification.