CJC-1295 DAC

Origin and the DAC Innovation

CJC-1295 DAC is the long-acting variant of the GHRH(1-29) analogue developed by ConjuChem Biotechnologies (Montreal) in the early 2000s. "CJC" refers to the company; "DAC" stands for Drug Affinity Complex — ConjuChem's proprietary platform for extending peptide half-life by covalent conjugation to circulating serum albumin. The molecule combines Modified GRF 1-29 (the same four-substitution GHRH analogue discussed on our CJC-1295 (no DAC) page) with a maleimidopropionic acid (MPA) linker attached at the C-terminal lysine.

On subcutaneous injection, the maleimide group of the MPA linker reacts rapidly and irreversibly with the free thiol of cysteine-34 on serum albumin, forming a stable thioether bond. The peptide is then carried through the circulation as a covalent passenger on albumin — a protein with its own 19-day half-life — producing an effective GHRH-analogue half-life on the order of 6 to 8 days in humans. This is the central pharmacokinetic difference between CJC-1295 DAC and Modified GRF 1-29, and it drives most of what is interesting and most of what is concerning about the variant.

Pulsatility Lost — and Why It Matters

Native GH secretion is pulsatile, with most output occurring in discrete bursts during slow-wave sleep. The short-acting CJC-1295 (and pure sermorelin) preserves this pulse biology: each injection produces a transient GH pulse that decays within hours. CJC-1295 DAC does not. The 6–8 day half-life means that after the first few injections, a near-continuous tonic elevation of GHRH-analogue signalling is established, producing what researchers have sometimes called a "GH bleed" — a chronic, non-pulsatile elevation of GH and IGF-1.

Whether non-pulsatile GH exposure reproduces the downstream benefits of pulsatile endogenous GH is an open physiologic question. The endocrinology literature on continuous versus pulsatile GH exposure is mixed; chronic exposure can blunt receptor responsiveness over time and alters IGF-1 binding protein dynamics in ways that are not obviously beneficial. This is a meaningful departure from physiological GH biology that CJC-1295 DAC users should understand.

Clinical Development and the Discontinuation

ConjuChem advanced CJC-1295 DAC into Phase 2 trials in the mid-2000s. The program was discontinued in 2007, with public discussion centering on a reported cardiovascular death during the trial — though ConjuChem never published a full adverse-event accounting. No regulatory filing for approval followed, and CJC-1295 DAC has no approved indication anywhere. This is an important difference from tesamorelin, the FDA-approved GHRH analogue in active clinical use.

Practical Considerations

Research protocols for CJC-1295 DAC typically use 1–2 mg per dose injected subcutaneously once or twice weekly, reflecting the long half-life. Because sustained receptor engagement is the pharmacologic state being created, dose timing is less critical than with short-acting analogues — the empty-stomach, pre-sleep discipline that governs Modified GRF 1-29 dosing is mostly irrelevant here. GHRP co-administration with ipamorelin is common but changes character compared with the pulse-synchronized pairing used with non-DAC CJC-1295: with DAC, the GHRP is layered over a continuous GHRH background rather than combined into a discrete pulse.

The side-effect profile tracks the long half-life. Facial flushing, water retention, and joint stiffness are reported more consistently and persist longer after dosing than with short-acting variants. Any adverse event that develops cannot be turned off in the near term — the drug has to wear off on its own timescale.

Safety and Regulatory Status

CJC-1295 DAC is not approved by the FDA or any other major regulator and carries the discontinued-development context noted above. It is listed on the World Anti-Doping Agency prohibited list at all times under class S2. Active malignancy is a contraindication; IGF-1 elevation is a plausible tumor-promotion risk and is of particular concern given the non-pulsatile exposure pattern. Supply is almost exclusively through research-chemical vendors with the usual quality and identity caveats — for a broader view of that supply chain, see our peptide sourcing guide.

Bottom Line

CJC-1295 DAC is a pharmacologically elegant molecule that deliberately departs from physiological GH biology, carries a discontinued clinical program, and has less real-world safety data than either its short-acting counterpart or tesamorelin. Anyone choosing between the DAC and non-DAC variants should start from the pulsatility question: if preserving pulse biology matters, the short-acting version is the rational choice.