CJC-1295 exists in two research forms that are routinely confused. The “DAC” suffix denotes a drug affinity complex — a covalent modification that dramatically extends plasma half-life. Without DAC, the same peptide is sometimes labelled “mod GRF 1-29” or “CJC-1295 no-DAC”. They are not the same molecule and the research applications differ. This is the comparison.
What CJC-1295 is at baseline
CJC-1295 is a synthetic analogue of the first 29 amino acids of growth hormone releasing hormone (GHRH 1-29), with four amino acid substitutions (D-Ala²-Gln⁸-Ala¹⁵-Leu²⁷) that resist enzymatic degradation. The substitutions extend the half-life from the endogenous GHRH’s ~7 minutes to roughly 30 minutes.
The DAC modification
The drug affinity complex is a maleimidopropionic acid linker added to the C-terminus of CJC-1295. After administration, the linker binds covalently to circulating serum albumin via a free cysteine residue. The peptide is then carried by albumin, which has a plasma half-life of approximately 19 days.
The result: CJC-1295 DAC has a plasma half-life of roughly 8 days, compared to ~30 minutes for the non-DAC form.
Half-life table
| Form | Modification | Half-life | Dosing frequency (research) |
|---|---|---|---|
| GHRH 1-29 (native) | none | ~7 min | multiple times daily |
| CJC-1295 (no DAC) | 4 amino acid substitutions | ~30 min | daily |
| CJC-1295 with DAC | substitutions + albumin linker | ~8 days | weekly |
GH pulse pattern — the critical difference
This is where the two forms diverge in research application.
CJC-1295 no-DAC produces a discrete GHRH stimulus that decays within hours. Endogenous GH pulses remain pulsatile — the researcher can model acute pulse amplification without disrupting the natural pulsatility pattern.
CJC-1295 DAC produces a near-continuous GHRH stimulus over its 8-day half-life. The pulsatility of endogenous GH release becomes attenuated — GH is elevated more continuously. This is a different physiological state and the research models that use it ask different questions.
Stacking with ghrelin receptor agonists
Both forms are commonly studied alongside ghrelin receptor agonists (ipamorelin, GHRP-6) because GHRH stimulus and GHS-R1a stimulus produce synergistic GH release. With no-DAC CJC-1295, pulse timing matters — the GHRP and the GHRH analogue need to peak concurrently. With DAC CJC-1295, the constant background GHRH signal means GHRP timing alone determines pulse amplitude.
Stability and reconstitution
Both forms are supplied lyophilised. Reconstitution in bacteriostatic water at 1–2 mg/mL is standard. Refrigerated reconstituted CJC-1295 retains potency for approximately 4 weeks. The DAC linker is sensitive to repeated freeze-thaw — single freeze-thaw is acceptable, multiple cycles degrade the linker integrity.
Choosing for the research question
- Acute GH pulse amplification — non-DAC
- Sustained GHRH receptor activation models — DAC
- Pulsatile pattern preservation — non-DAC
- Reduced dosing frequency / steady-state models — DAC
Chempeptides supplies both forms with batch-specific CoA — see the research catalogue for current availability. Research use only.