Research Protocols / Growth Axis
CJC-1295 No DAC research protocols: half-life, pulsatility, and published findings
CJC-1295 without DAC is a tetrasubstituted GRF 1-29 analogue with a half-life measured in minutes, not days. That single property drives every protocol decision in the published literature, and it is the thing most summaries get wrong.
The naming around this compound causes more protocol errors than the pharmacology does. CJC-1295 with DAC and CJC-1295 without DAC are not two doses of one compound. They are two molecules with half-lives that differ by roughly three orders of magnitude, and substituting one for the other invalidates any comparison to published data.
What the molecule is
CJC-1295 without DAC is modified GRF 1-29: the first 29 residues of growth-hormone-releasing hormone, carrying four amino acid substitutions that resist enzymatic degradation. GHRH itself has a circulating half-life near 7 minutes, largely because dipeptidyl peptidase-4 (DPP-4) cleaves it rapidly at the N-terminus. The substitutions in modified GRF 1-29 blunt that cleavage, extending the half-life to roughly 30 minutes in published measurements.
The DAC variant adds a Drug Affinity Complex, a maleimidopropionic acid group that covalently binds circulating serum albumin. Albumin binding extends the half-life to approximately 6 to 8 days. Same receptor, radically different exposure profile.
| Property | CJC-1295 No DAC | CJC-1295 with DAC |
|---|---|---|
| Also called | Modified GRF 1-29, Mod GRF | CJC-1295 DAC |
| Approximate half-life | ~30 minutes | ~6 to 8 days |
| Albumin binding | No | Yes, covalent |
| GH release pattern | Discrete pulse | Sustained elevation, bleed |
| Research use case | Studying pulsatile GH signalling | Studying sustained GHRH-receptor occupancy |
Why pulsatility is the whole point
Endogenous growth hormone is not secreted continuously. It is released in discrete pulses, predominantly during slow-wave sleep, with near-baseline troughs between them. A substantial body of endocrine literature indicates that downstream signalling is sensitive to that pattern, not merely to total exposure. Continuous elevation and pulsatile elevation with the same area under the curve produce measurably different hepatic IGF-1 responses and different receptor regulation.
This is why the No-DAC variant is the more common tool in mechanistic research. Its short half-life produces a discrete GH pulse that decays before the next administration, preserving the trough. The DAC variant produces what the literature calls a bleed, a sustained elevation that flattens pulsatility. Neither is better in the abstract. They answer different questions.
If a protocol you are reading treats No-DAC and DAC as interchangeable, or quotes a weekly schedule for the No-DAC variant, it was not written from the primary literature.
Reconstitution for a 10 mg vial
Our CJC-1295 No DAC ships as a 10 mg lyophilized vial at 99.34% HPLC purity on the current lot. Common stock preparations:
| Water added | Resulting concentration | Per 0.1 mL draw |
|---|---|---|
| 2 mL | 5 mg/mL (5000 mcg/mL) | 500 mcg |
| 5 mL | 2 mg/mL (2000 mcg/mL) | 200 mcg |
| 10 mL | 1 mg/mL (1000 mcg/mL) | 100 mcg |
Add the solvent slowly down the vial wall rather than directly onto the lyophilized cake. GHRH analogues are not especially fragile, but shear from a direct stream causes foaming, and foam traps peptide at the air-liquid interface where it denatures. Swirl, never shake. Full method in our reconstitution guide.
The ipamorelin pairing in the literature
GHRH analogues and ghrelin-receptor agonists act through distinct receptors, GHRHR and GHS-R1a respectively, and published work reports synergistic rather than merely additive GH release when both pathways are stimulated. That is the mechanistic basis for the widely studied CJC-1295 plus ipamorelin combination. We cover the pairing in detail in the stack protocol article, and we supply the combination as a pre-blended reference standard for labs that want lot-matched material.
Tolerability signals in the literature
Reported observations in the GHRH-analogue literature centre on injection-site reactions in animal models and transient effects attributable to GH elevation itself rather than to the analogue. Because the No-DAC variant clears within about 30 minutes, exposure-related observations are correspondingly brief. There is no Health Canada authorization for this compound in any context, and the human clinical dataset for the No-DAC variant specifically is thin. Treat any protocol quoting confident human outcome figures with scepticism.
Sourcing and verification
Purity matters more than any protocol detail. A concentration curve computed from a vial that is 88% peptide and 12% truncated sequence is not reproducible, and the failure is invisible until you compare it against another lot. Every Lumera Labs lot ships with a lot-specific certificate of analysis reporting HPLC-UV purity, and those certificates are posted publicly at Lab Results before you order, not emailed afterward. Orders ship from within Canada in 24 to 48 hours, free over $200 CAD, so there is no customs exposure and no multi-week transit window for temperature-sensitive material.
FAQ
What is the difference between CJC-1295 with and without DAC?
They are different molecules. The No-DAC variant, modified GRF 1-29, has a half-life near 30 minutes and produces a discrete GH pulse. The DAC variant carries a Drug Affinity Complex that binds serum albumin covalently, extending the half-life to roughly 6 to 8 days and producing sustained elevation rather than pulses.
Is CJC-1295 No DAC the same as modified GRF 1-29?
Yes. Modified GRF 1-29, Mod GRF 1-29, and CJC-1295 without DAC all refer to the same tetrasubstituted 29-residue GHRH fragment. The naming overlap is a persistent source of protocol confusion.
How do I reconstitute a 10 mg CJC-1295 vial?
2 mL of bacteriostatic water gives 5 mg/mL, 5 mL gives 2 mg/mL, and 10 mL gives 1 mg/mL. Add solvent slowly down the vial wall rather than onto the cake, and swirl rather than shake to avoid foaming.
Why is CJC-1295 studied together with ipamorelin?
They act on different receptors, GHRHR and GHS-R1a. Published work reports synergistic rather than additive GH release when both pathways are stimulated simultaneously, which is the mechanistic basis for studying them as a pair.
Why does pulsatility matter in GH research?
Endogenous GH is released in discrete pulses with near-baseline troughs. Endocrine literature indicates downstream signalling responds to that pattern, not just total exposure. Continuous and pulsatile elevation at matched area under the curve produce different hepatic IGF-1 responses.
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