What Is CJC 1295? (GHRH Analog Mechanism Explained)

Here's the thing that trips up almost everyone researching this compound: the vial most suppliers label CJC 1295 no DAC is chemically a different molecule from the one that carries the name in published pharmacology. Same peptide backbone. Clearance profiles that differ by orders of magnitude.

Our team fields this question constantly from lab buyers staring at two listings with nearly identical names and completely different specification sheets. Once you see where the naming split happened, the rest of the pharmacology falls into place fast.

What is CJC 1295?

CJC 1295 is a synthetic analog of growth hormone-releasing hormone (GHRH), built on the first 29 amino acids of the natural hormone with four amino acid substitutions that resist enzymatic breakdown. It binds the GHRH receptor on pituitary somatotroph cells to stimulate growth hormone release. The DAC variant attaches to circulating albumin, stretching its life from minutes into days.

The oversimplification worth correcting immediately: this compound does not add growth hormone to a system. It asks the pituitary to release more of its own, which means every existing feedback brake still applies. What follows covers the chemistry behind those four substitutions, how the DAC linker binds albumin, what actually separates the two variants on the bench, and why the certificate of analysis decides whether a batch produces usable data.

The molecule behind the name

CJC 1295 starts as GRF (1-29), the first 29 amino acids of growth hormone-releasing hormone and the shortest fragment that retains full activity at the receptor. On its own that fragment is fragile. Dipeptidyl peptidase-4 (DPP-4), an enzyme abundant in plasma, clips it at the second residue almost immediately.

Four substitutions solve that. D-Ala at position 2 blocks the DPP-4 cleavage site. Gln at position 8 prevents asparagine deamidation. Ala at 15 improves binding stability. Leu at 27 removes a methionine prone to oxidation. The product is tetrasubstituted GRF (1-29), also written as modified GRF (1-29), a short peptide of roughly 3.4 kilodaltons.

Then comes the fork in the road. ConjuChem, the company behind the original compound, attached a Drug Affinity Complex (DAC) to the C-terminus. The name CJC 1295 in the peer-reviewed literature refers to that DAC-bearing molecule. The linker-free tetrasubstituted peptide picked up the retronym CJC 1295 no DAC across the research supply market, which is a borrowed name rather than a chemical description.

We've watched this cause genuine ordering errors. A researcher reads a pharmacokinetic paper on the DAC compound, orders the no-DAC vial, and receives a molecule whose clearance behaviour looks nothing like the paper's figures.

How the signal actually reaches the pituitary

CJC 1295 works by binding the GHRH receptor (GHRHR), a class B G-protein-coupled receptor expressed on somatotroph cells in the anterior pituitary. Receptor occupancy activates the Gs protein, which switches on adenylyl cyclase, raising intracellular cAMP. cAMP activates protein kinase A, which phosphorylates the transcription factor CREB, which in turn drives Pit-1 dependent transcription of the growth hormone gene alongside immediate release of stored GH vesicles. Circulating GH then reaches hepatocytes and stimulates production of IGF-1 (insulin-like growth factor 1), the mediator responsible for much of the downstream biology.

So what does CJC 1295 do that introducing exogenous growth hormone would not? It leaves the regulatory architecture intact.

Here's the part most explainers skip. Somatotrophs are not a tap you open wider. Somatostatin, also called somatotropin release-inhibiting factor, sits on the same cells and functionally mutes GHRH signalling when hypothalamic somatostatin tone is high. A GHRH analog raises the amplitude of pulses the hypothalamus already permits. It cannot push through a closed gate, and rising IGF-1 feeds back to increase somatostatin release, closing that gate further.

That ceiling is the reason combination pharmacology exists in this space. GHS-R1a agonists such as ipamorelin act on the ghrelin receptor, a separate target, and reduce somatostatin output rather than pressing harder on the same door. In our experience reviewing study designs, ignoring the somatostatin variable is the single most common reason GHRH analog data comes out messier than expected.

What the DAC linker changes, and why

The DAC in CJC 1295 with DAC stands for Drug Affinity Complex: a maleimidoproprionyl group joined through a lysine linker at the peptide's C-terminus. Maleimide chemistry reacts selectively with free thiol groups, and the most abundant free thiol in blood is cysteine-34 on serum albumin. The linker forms a covalent bond at that site, and the peptide then circulates as a passenger on a carrier protein with a naturally long residence time.

Published pharmacokinetic work on the DAC-bearing analog describes persistence measured in days rather than minutes, with IGF-1 remaining elevated well beyond a single exposure. We deliberately avoid quoting one precise half-life figure here. Reported values vary across studies and assay methods, and a confident number stripped of its context is worse than an honest range.

CJC 1295 no DAC behaves in the opposite direction. With no albumin anchor, it clears quickly, and the resulting GH response reads as a discrete spike returning toward baseline. That sustained versus transient distinction is a real experimental variable, not vendor language. Continuous agonist exposure raises receptor desensitisation questions that intermittent exposure simply does not, which is why investigators studying pulsatile physiology and investigators studying sustained receptor occupancy reach for different vials.

One practical consequence: pharmacokinetic data from one variant cannot be mapped onto the other. They share a sequence, not a profile.

Research applications and the paperwork that makes them valid

In legitimate settings, CJC 1295 is used as a laboratory research tool for studying the GHRH, GH and IGF-1 axis. Investigation in this area spans receptor pharmacology, GH pulse architecture, IGF-1 signalling, lipolysis and body composition models, the coupling between slow-wave sleep and nocturnal GH release, and combination work with ghrelin-receptor agonists. Research suggests the class has real translational interest, and there is regulatory precedent worth naming precisely: tesamorelin is a GHRH analog with FDA approval for one specific medical indication.

This compound holds no such approval. Real Peptides supplies it strictly for laboratory research, and it is not for human or veterinary consumption. If concerns about an animal's health are what brought you to this page, talk to your veterinarian rather than a peptide supplier.

Now the part that decides whether a batch is worth anything. Two figures on a certificate of analysis get conflated constantly. Chromatographic purity, measured by HPLC, tells you what fraction of the peptide material present is the target sequence. Net peptide content tells you what fraction of the vial's total mass is peptide at all, as opposed to residual water, acetate counterions and salts. A vial can read 99% pure by HPLC and still hold noticeably less peptide than the label suggests when net content goes unreported. Mass spectrometry confirms identity; HPLC confirms purity; neither one substitutes for the other.

That is why every batch of our CJC 1295 no DAC ships with its own certificate rather than a generic sequence sheet. Across the third-party documentation our team has reviewed, the most common gap isn't a failing purity number. It's a missing net peptide content line.

CJC 1295 With DAC vs No DAC: Side-by-Side

The two forms share an identical amino acid sequence and differ by one linker. That single structural difference cascades through every property that matters experimentally.

What If: Laboratory Sourcing Scenarios

What if a shipment of lyophilised peptide arrives warm?

Document the excursion, then check the supplier's stability data before the material enters an experiment. Lyophilised peptides tolerate short ambient excursions far better than reconstituted solutions do, because hydrolysis and aggregation both require water as a medium. Long-term storage of lyophilised material is standard at -20C or below, with reconstituted material held at 2-8C. A single transit excursion is usually not disqualifying on its own. An unknown thermal history, with no documented chain of custody, is a different problem entirely.

What if two suppliers list the same compound under different names?

Compare sequences and linkers rather than product titles. Modified GRF (1-29), tetrasubstituted GRF (1-29), and the no-DAC designation all describe the same 29-residue peptide with the same four substitutions. A listing that names the DAC linker explicitly and a listing that omits it may or may not be the same material, and the product page alone will not tell you. The certificate of analysis, showing mass spectrometry identity confirmation, settles the question in seconds.

What if the pharmacokinetics in a cited paper don't match the material on the bench?

Check which variant the paper studied before assuming a handling error. Most published pharmacology under the CJC name examined the albumin-binding form, so any comparison against linker-free material will diverge sharply on duration, IGF-1 persistence and release pattern. This is the most frequent source of confusion we encounter from research teams new to the class, and it is a literature-matching problem rather than a material-quality problem.

The unglamorous truth about sourcing this class of peptide

Let's be direct about this: the largest variable in GHRH analog research is not the choice between the two variants. It's whether the contents of the vial match the label on it. A beautifully designed pulsatility study collapses if the material is 78% target sequence with unreported net peptide content, and no amount of experimental rigour downstream will surface that error. Batch-level HPLC and mass spectrometry, published and traceable to the specific lot in hand, is the only thing standing between a research-grade compound and an expensive unknown. Anonymous supply chains cannot provide that, and generic sequence sheets recycled across every batch are not documentation.

The information here is educational and describes what the research literature reports about a laboratory compound. If you're comparing the two forms before ordering, our CJC 1295 overview breaks them down by specification, the no-DAC listing carries current batch details, and every result we publish sits in the certificate of analysis library. The broader research catalog and our facility and shipping information cover everything else.

CJC 1295 generates so much confusion for one reason: a marketing retronym got attached to a molecule the original literature never described, and thousands of research pages have repeated the conflation since. The chemistry itself is refreshingly clean. Four substitutions buy stability, one linker buys albumin binding, and the pituitary does exactly what its own feedback loops allow it to do. Read the sequence, read the linker, read the certificate. The name on the label is the least reliable piece of information in the whole transaction.

References

Peer-reviewed sources on CJC-1295 indexed in PubMed, listed for research context. Real Peptides supplies CJC-1295 for laboratory research use only.

1. Netnography of Female Use of the Synthetic Growth Hormone CJC-1295: Pulses and Potions. Substance use & misuse, 2016. PMID 26771670. doi:10.3109/10826084.2015.1082595
2. Identification of CJC-1295, a growth-hormone-releasing peptide, in an unknown pharmaceutical preparation. Drug testing and analysis, 2010. PMID 21204297. doi:10.1002/dta.233
3. Activation of the GH/IGF-1 axis by CJC-1295, a long-acting GHRH analog, results in serum protein profile changes in normal adult subjects. Growth hormone & IGF research : official journal of the Growth Hormone Research Society and the International IGF Research Society, 2009. PMID 19386527. doi:10.1016/j.ghir.2009.03.001
4. 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. The Journal of clinical endocrinology and metabolism, 2006. PMID 16352683. doi:10.1210/jc.2005-1536
5. Once-daily administration of CJC-1295, a long-acting growth hormone-releasing hormone (GHRH) analog, normalizes growth in the GHRH knockout mouse. American journal of physiology. Endocrinology and metabolism, 2006. PMID 16822960. doi:10.1152/ajpendo.00201.2006
6. Pulsatile secretion of growth hormone (GH) persists during continuous stimulation by CJC-1295, a long-acting GH-releasing hormone analog. The Journal of clinical endocrinology and metabolism, 2006. PMID 17018654. doi:10.1210/jc.2006-1702
7. 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. PMID 15817669. doi:10.1210/en.2004-1286