CJC-1295 DAC: Mechanism, 6-8 Day Half-Life, and Research Applications

Quick answer: CJC-1295 DAC is a synthetic analog of growth hormone-releasing hormone (GHRH). It is modified with a Drug Affinity Complex (DAC) that covalently binds serum albumin. This overview covers how that binding extends its half-life from roughly 30 minutes (unmodified GHRH fragments) to 6-8 days. This will help researchers understand the pharmacokinetics before working with this drug. It's studied for sustained GH and IGF-1 elevation while preserving natural pulsatile release. It's not FDA-approved and is banned under WADA category S2.

This guide is written for researchers, students, and anyone trying to understand what's actually established about CJC-1295 DAC versus what's assumed. It covers the mechanism, the pharmacokinetics, the human data that exists, and the current regulatory status. That matters because CJC-1295 is one of the few research peptides with a detailed, documented FDA safety review behind it, rather than just silence or ambiguity.

An engineering fix for a biology problem

Growth hormone-releasing hormone is the signal your hypothalamus sends the pituitary to release GH. It has a real design flaw if you're trying to study it, though. It disappears from the bloodstream in about seven minutes, a matter of drug elimination and distribution rather than a weak signal to begin with.

Enzymes chew it up almost as fast as it's released. That made GHRH itself nearly useless as a research or clinical tool. By the time you'd measured an effect, the molecule was already gone.

CJC-1295 was built to solve exactly that problem, and it did it twice, in two different ways, which is why you'll see two different compounds sharing one name.

Two molecules, one name

The base molecule is a 29-amino-acid fragment of GHRH. It carries four substitutions, at positions 2, 8, 15, and 27, that resist the enzyme DPP-4, responsible for GHRH's rapid breakdown.

On its own, this version is often called Modified GRF(1-29), or "CJC-1295 without DAC." It pushes the half-life out to about 30 minutes. That's better than seven minutes, but the time required between doses to maintain any signal is still short - a real practical constraint once you factor it into research knowledge of the compound.

The second version bolts on a Drug Affinity Complex: a maleimidopropionic acid linker attached to a lysine residue on the peptide. After injection, that linker forms a covalent bond with Cys34 on circulating serum albumin. It's not a loose, reversible attachment. It's a permanent one.

The peptide effectively hitches a ride on one of the most abundant, longest-lived proteins in blood plasma. That's CJC-1295 with DAC, and it's the version behind the 6-to-8-day half-life you'll see quoted everywhere (CAS 446262-90-4).

Once released from the albumin complex, CJC-1295 acts on the GHRH receptor, a Class B G protein-coupled receptor on pituitary somatotroph cells. Binding activates the receptor's downstream signaling cascade, including protein kinase A (PKA) activation via cyclic AMP, which is the pathway that ultimately triggers GH release from the cell.

What the albumin trick actually buys you

Binding to albumin does two things at once. It shields the peptide from the enzymes that would otherwise break it down in minutes. It also dramatically slows renal clearance, since albumin itself is too large to be filtered out by the kidneys quickly.

The peptide gets released gradually as the albumin-peptide complex circulates. Researchers describe this as a depot effect - a slow trickle of active compound rather than a single spike.

The foundational preclinical paper on this, from Jetté and colleagues in 2005, characterized exactly this behavior in rats. Their research efforts focused on how the albumin-bound GHRH analog activated pituitary GHRH receptors and held elevated activity far longer than the free peptide. That paper is the one that first identified CJC-1295 as what the authors called a "long-lasting GRF analog."

Pharmacokinetics: what about half-life

Half-life gets thrown around constantly in peptide research discussions, but it's worth being precise about what it means: the time it takes for a drug's concentration in the body to fall by half. It's not a hard cutoff where the compound disappears - it's an exponential decay curve, and a useful rule of thumb is that a drug reaches steady state, meaning its concentration stops meaningfully rising with continued dosing, after roughly five half-lives.

That's exactly why the DAC modification matters so much. Drugs with longer half-lives can be dosed less frequently while maintaining a stable concentration, which is the whole design rationale behind attaching a GHRH fragment to albumin in the first place. Like most compounds, CJC-1295's half-life isn't a fixed universal number - factors like age and metabolic rate affect how quickly any given drug is cleared from an individual's system, which is part of why PK studies report ranges rather than a single value.

On the clearance side, CJC-1295 is broken down through normal peptide metabolism - enzymatic cleavage by circulating peptidases - and eliminated by renal excretion, the same general pathway most peptide drugs follow once they've dissociated from albumin or been broken down into smaller fragments.

Does it actually raise GH and IGF-1, and does that matter?

Two human studies from 2006 form the core evidence base here. Teichman and colleagues gave healthy adults single and repeated doses of CJC-1295 DAC. Mean plasma IGF-1 rose 1.5- to 3-fold, an elevation that persisted 9 to 11 days after a single dose.

A separate study by Ionescu and Frohman looked at whether this sustained elevation came at a cost to normal GH physiology. It found that it didn't. GH is normally released in pulses, and those pulses matter for how target tissues respond to it. Continuous, non-pulsatile GH exposure, the kind you get from directly injecting synthetic GH, can blunt the body's own signaling over time. Ionescu and Frohman found CJC-1295 raised trough and mean GH levels while preserving the pulsatile pattern - a meaningfully different profile from straight GH administration.

That's a real and specific finding, not a vague "boosts growth hormone" claim: the mechanism appears to raise the baseline without flattening the natural rhythm. It's the kind of detail that matters for an honest assessment of the compound, since it closes a real gap between "raises a hormone level" and "does so in a way that preserves normal physiology" - and it's part of why CJC-1295 has held research interest for as long as it has.

The clinical research efforts that didn't yield

CJC-1295 DAC did reach a Phase 2 trial. ConjuChem, the Canadian company that developed it, ran a randomized, placebo-controlled study in 192 HIV-positive adults with visceral obesity, through a multicenter collaboration testing two dose levels against placebo over 12 weeks.

The trial was halted in July 2006, after one enrolled participant died at a study site in Argentina. At the time, the cause of death and its relationship to the drug were still under investigation, and ConjuChem didn't release further detail publicly. CJC-1295 was never advanced further or filed for approval anywhere.

That's worth sitting with. This isn't a compound that never got tested in people. It went further than most research peptides ever do, with 192 enrolled participants, and development still stopped. No modern trial has since reopened the question. The practical result today is the same either way: no approved drug, and no completed later-phase trial exists.

The regulatory story: flagged, then formally rejected

CJC-1295's path through U.S. drug-compounding rules is more detailed than most peptides get, because it actually went through the full review process.

In September 2023, the FDA placed CJC-1295 in Category 2 of its interim bulk drug substances list. That's the category reserved for compounds the agency considers to carry significant safety risk, alongside more than a dozen other peptides.

In September 2024, that Category 2 listing was withdrawn on procedural grounds, after the original nominator pulled the nomination. That might sound like good news. What happened next matters more: the FDA still referred CJC-1295 to a full Pharmacy Compounding Advisory Committee (PCAC) review in December 2024.

The committee voted against including CJC-1295 on the approved 503A bulks list, meaning pharmacies still can't legally compound it. The stated reasons were specific:

• Nonclinical toxicity findings, including DNA damage observed in pituitary cells

• Injection-site necrosis

• An unresolved cardiac signal tied to the 2006 trial's termination

• Immunogenicity concerns

That's a substantially more detailed rejection than a simple "insufficient data" call. It's a committee weighing actual toxicology findings and coming down against compounding.

For research purposes, the bottom line hasn't moved: no FDA approval for any human indication, and as of the most recent advisory review, no path to legal pharmacy compounding either.

Banned in sports, without ambiguity

Unlike some newer research peptides where the anti-doping classification is genuinely disputed, CJC-1295's status isn't in question. GHRH and its analogs, including the likes of sermorelin, tesamorelin, and CJC-1295, are explicitly listed under WADA category S2, covering peptide hormones, growth factors, and related substances. That prohibition applies at all times, in and out of competition, for any athlete subject to WADA testing. It doesn't depend on the strength of the underlying research.

What this actually tells a researcher

Put together, CJC-1295 DAC is one of the better-characterized entries in the growth hormone research peptide category - a genuine engineering solution to a real pharmacokinetic problem, backed by a preclinical mechanism paper and two published human studies. It's also one of the few peptides in this space where a completed FDA advisory review, rather than silence or ambiguity, spells out specific safety findings. That combination of real human data, a documented rejection, and no approved pathway forward is different from a peptide that simply hasn't been reviewed yet, and it's worth keeping that distinction in mind to understand any proposed research application, or when comparing it to compounds like BPC-157, which has drawn far less formal regulatory scrutiny despite far less human data existing either way.

FAQ

What does DAC actually stand for, and what does it do? 

Drug Affinity Complex is a chemical linker that permanently binds the peptide to serum albumin in the blood, turning a molecule that would normally last minutes into one that lasts days.

Is CJC-1295 DAC the same as CJC-1295 without DAC? 

No. They share the same core amino acid sequence, but the DAC version's half-life is measured in days, while the non-DAC version's is measured in minutes. They're studied differently and shouldn't be treated as interchangeable.

Is CJC-1295 legal to research? 

It's not FDA-approved for human use, and pharmacy compounding was formally rejected in December 2024 following a safety review. It's also prohibited under WADA at all times for tested athletes.

Why did the FDA advisory committee reject it? 

The committee cited specific nonclinical toxicity findings like DNA damage in pituitary cells and injection-site necrosis, along with an unresolved cardiac signal from the compound's 2006 clinical trial and immunogenicity concerns.

Has it been tested in humans at all? 

Yes, more than most research peptides. Two published studies from 2006 measured GH and IGF-1 responses in healthy adults. A Phase 2 trial also ran in 192 HIV-positive adults before being halted in July 2006, after a participant's death whose cause was under investigation at the time. No later-phase or approved use has followed.

This article is for research and educational purposes only. All compounds described are for laboratory use only and are not approved by the FDA for human use. RCD bio products are not intended to diagnose, prevent, treat, or cure any disease or medical condition.

ATTENTION: All RCDbio products are strictly for LABORATORY AND RESEARCH PURPOSES ONLY. They are not intended for human consumption, veterinary use, or any other non-research application. For queries or support, contact support@rcdbio.co 

References

1. Jetté L, Léger R, Thibaudeau K, et al. Human growth hormone-releasing factor (hGRF)1-29-albumin bioconjugates activate the GRF receptor on the anterior pituitary in rats: identification of CJC-1295 as a long-lasting GRF analog. Endocrinology. 2005;146(7):3052-3058. PMID: 15817669. https://pubmed.ncbi.nlm.nih.gov/15817669/ 

2. Teichman SL, Neale A, Lawrence B, Gagnon C, Castaigne JP, Frohman LA. Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults. J Clin Endocrinol Metab. 2006;91(3):799-805. PMID: 16352683. https://pubmed.ncbi.nlm.nih.gov/16352683/ 

3. Ionescu M, Frohman LA. Pulsatile secretion of growth hormone (GH) persists during continuous stimulation by CJC-1295, a long-acting GH-releasing hormone analog. J Clin Endocrinol Metab. 2006;91(12):4792-4797. PMID: 17018654. https://pubmed.ncbi.nlm.nih.gov/17018654/ 

4. ConjuChem Biotechnologies. A Study to Evaluate CJC-1295 in HIV-Positive Adults With Excess Abdominal Fat. ClinicalTrials.gov. NCT00267527. https://clinicaltrials.gov/study/NCT00267527 

5. Lipodystrophy study halted after patient death. aidsmap. 2006. https://www.aidsmap.com/news/jul-2006/lipodystrophy-study-halted-after-patient-death 

6. FDA Pharmacy Compounding Advisory Committee. Briefing document on CJC-1295-related bulk drug substances. December 4, 2024. https://www.fda.gov/media/183583/download 

7. FDA. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (503A Category 2 list, September 2023 update). https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks