Overview
CJC-1295 is a synthetic analog of growth hormone-releasing hormone (GHRH) developed to extend the half-life of native GHRH (1–44). Two primary variants are used in research: CJC-1295 with DAC (drug affinity complex) and CJC-1295 without DAC (also called Mod GRF 1–29). Both share the same core GHRH-analog sequence but differ dramatically in pharmacokinetics due to the DAC modification.
Mechanism and Half-Life
CJC-1295 with DAC incorporates a lysine-maleimide linker that covalently binds to circulating albumin after injection. This albumin binding shields the peptide from enzymatic degradation and renal clearance, extending the biological half-life to approximately 6–8 days. A single dose can sustain elevated GH-axis stimulation across multiple days, producing a blunted but prolonged GH release pattern rather than discrete pulses.
CJC-1295 without DAC (Mod GRF 1–29) retains a half-life of 25–30 minutes — significantly longer than native GHRH (approximately 7 minutes) due to amino acid substitutions at positions 2, 8, 15, and 27, but without albumin binding. It produces sharp, physiologically mimetic GH pulses when administered, making it the preferred research tool when pulse amplitude and timing need to be controlled independently.
Key Differences
| Parameter | CJC-1295 with DAC | CJC-1295 No DAC (Mod GRF 1–29) |
|---|---|---|
| Half-life | ~6–8 days | ~25–30 min |
| GH release pattern | Sustained, blunted | Discrete pulses |
| Dosing frequency | 1–2×/week in research models | Multiple times daily |
| Albumin binding | Yes (covalent DAC) | No |
| IGF-1 elevation | Sustained | Pulsatile |
| Purity sensitivity | DAC linkage requires strict storage | Standard peptide storage |
Research Applications
Researchers studying chronic GH-axis stimulation, body composition changes over weeks, or IGF-1 upregulation in animal models typically use CJC-1295 with DAC for practical dosing frequency. Studies focused on GH pulse dynamics, neuroendocrine feedback, or co-administration with GH secretagogues such as GHRP-2 or Ipamorelin generally prefer No DAC to preserve pulsatile physiology.
Laboratory Considerations
Both variants are supplied lyophilized and reconstituted with bacteriostatic water. CJC-1295 with DAC should be stored at −20°C after reconstitution and used within 4 weeks; the DAC linkage is more sensitive to freeze-thaw cycles than the no-DAC form. No DAC reconstituted solutions remain stable at 4°C for up to 3 weeks. Neither variant should be vortexed — gentle swirling prevents aggregation at the maleimide linker site.
Research Disclaimer: All compounds discussed are intended exclusively for laboratory and research purposes. This content is not medical advice. Bastion Peptides products are not approved for human use, consumption, or therapeutic application.
