CJC-1295 without DAC — commonly catalogued as modified GRF(1-29) or mod-GRF(1-29) — is a synthetic analog of the biologically active N-terminal portion of human growth-hormone-releasing hormone. It carries a small set of engineered residue substitutions that resist enzymatic breakdown, but it deliberately omits the drug-affinity-complex (DAC) linker found on the long-acting variant. The result is a compact, stabilized peptide that is well suited to laboratory investigation of the growth-hormone axis.
The GHRH(1-29) starting point
Native GHRH is a 44-residue peptide, but its receptor-activating information is concentrated in the first 29 amino acids. Working from that truncated scaffold keeps the molecule short enough for efficient chemical assembly while preserving the sequence elements that engage the receptor, as described in its mechanism of action. Reading and interpreting that ordered residue string follows general amino acid sequence conventions.
Stabilizing substitutions
The characteristic modifications sit at positions that are otherwise vulnerable to rapid proteolysis. Substitutions near the N-terminus blunt cleavage by dipeptidyl peptidase-4, and additional swaps reduce oxidation and trypsin-like susceptibility. Collectively these changes extend in-vitro stability relative to unmodified GHRH(1-29), which is the practical value that made the analog attractive as a reagent.
No DAC linker
Because this form lacks the maleimidopropionyl (DAC) group, it does not form a covalent bond with circulating albumin the way the DAC variant does. That single structural fork is the reason the two molecules behave so differently in duration terms, and it is why comparative work often pairs them directly.
Solid-phase assembly
The peptide is produced by stepwise solid-phase peptide synthesis, in which protected amino acids are coupled one at a time onto a resin-bound growing chain. After cleavage from the resin and side-chain deprotection, the crude product is purified chromatographically to remove truncated and deletion sequences.
Purification, drying, and QC
Following purification the peptide is typically lyophilized for stability during storage and transport (what is lyophilization), then characterized for identity and purity by HPLC purity analysis and complementary mass measurement. Broader background is in the CJC-1295 no-DAC research overview.
Product page: CJC-1295 (No DAC) research vials.
Research Use Only. Supplied strictly for laboratory research and development — not for human or veterinary use, consumption, or any therapeutic or diagnostic purpose. This article is research education, not usage guidance.