CJC-1295 with DAC - Frequently Asked Questions

It is a synthetic growth-hormone-releasing hormone (GHRH/GRF) analog, specifically an albumin-binding long-acting secretagogue peptide. DAC stands for Drug Affinity Complex, the albumin-binding feature that distinguishes this version. Its backbone is the GRF(1-29) sequence (sermorelin) with four substitutions plus a C-terminal albumin-binding linker.

It is a 30-residue peptide: Tyr-D-Ala-Asp-Ala-Ile-Phe-Thr-Gln-Ser-Tyr-Arg-Lys-Val-Leu-Ala-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Leu-Ser-Arg-Lys. The backbone is GRF(1-29) with substitutions D-Ala2, Gln8, Ala15 and Leu27, plus a C-terminal Lys30 bearing an Nepsilon-maleimidopropionyl DAC linker.

The GRF(1-29) backbone is a ligand for the growth-hormone-releasing-hormone receptor (GHRHR), a class-B secretin-family Gs-coupled G-protein-coupled receptor expressed on pituitary somatotroph cells, as described in the Halmos et al. 2025 review (PMID 39934495).

The C-terminal Lys30 carries an Nepsilon-maleimidopropionyl linker whose maleimide reacts selectively with the single free thiol of cysteine-34 on serum albumin, forming a stable thioether bioconjugate at 1:1 loading. The cited chemistry (Leger et al. 2004, PMID 15357960) reports roughly 1000-fold accelerated reactivity toward that thiol versus other thiols. This albumin tethering is the structural basis for the molecule's extended plasma residence.

The substitutions D-Ala2, Gln8, Ala15 and Leu27 reduce susceptibility to dipeptidyl-peptidase-IV and other proteolytic cleavage in vitro, hardening the backbone against enzymatic degradation while preserving GHRHR recognition.

The free pre-conjugation DAC peptide has a molecular weight near 3647 g/mol (commonly cited ~3647.8 g/mol). The molecular formula is C165H269N47O46 (PubChem CID 91971820), with some vendor sources listing C165H271N47O46; the entry treats the PubChem value as primary. The CAS number is 863288-34-0. After conjugation to ~66.5 kDa albumin the effective circulating mass is about 70 kDa.

An estimated plasma half-life of 5.8 to 8.1 days after a single subcutaneous dose is attributed to Teichman et al. 2006 in JCEM (PMID 16352683). This is the only peptide-specific half-life value the source data supports and should be read as a reported pharmacokinetic estimate from that study.

Per Teichman et al. 2006 and Ionescu and Frohman 2006 (PMID 17018654), a single dose raised mean plasma GH roughly 2 to 10-fold for more than six days and IGF-1 roughly 1.5 to 3-fold for nine to eleven days, with preserved GH pulsatility and no rise in prolactin, cortisol or ACTH. These are the only quantitative output figures the data supports.

Ligand binding to GHRHR promotes coupling to the stimulatory Gs protein, activating adenylate cyclase and raising intracellular cyclic AMP. cAMP activates protein kinase A, which phosphorylates the CREB transcription factor and, with Pit-1, modulates growth-hormone gene transcription, alongside an increase in intracellular calcium.

For laboratory handling only, the lyophilized peptide is dissolved in bacteriostatic water. The resulting concentration equals the vial mass divided by the diluent volume; for example, 5 mg in 2 mL gives 2.5 mg/mL. The ~3647 g/mol free mass can convert that to molarity. Reconstituted stock is conventionally refrigerated for near-term use or frozen for longer storage, with freeze-thaw cycles minimized. This is benchtop preparation guidance, not a human dosing protocol.

No. This is research-use-only reference material. All statements describe in-vitro receptor coupling, conjugation chemistry, and reported preclinical or pharmacokinetic findings from the cited sources, not clinical outcomes or any form of human administration.