Few naming conventions in peptide research cause as much confusion as CJC-1295 no DAC versus CJC-1295 with DAC. Both names describe analogues of growth hormone-releasing hormone (GHRH), both share the same modified 29-residue backbone, and both are frequently shortened to "CJC-1295". Yet they are chemically distinct molecules with very different pharmacokinetic profiles. This article explains where the difference lies, where the names came from and how the two are described in the published literature.
For laboratory research use only. Not for human or veterinary use. See our research use only policy.
For a wider view of this peptide family, including the GHRP ipamorelin, see our pillar guide to CJC-1295 and ipamorelin in research.
At a glance: CJC-1295 no DAC
- Name: CJC-1295 no DAC
- Synonyms: Modified GRF (1-29), Mod GRF 1-29, tetrasubstituted GRF (1-29)
- Sequence: Tyr-D-Ala-Asp-Ala-Ile-Phe-Thr-Gln-Ser-Tyr-Arg-Lys-Val-Leu-Ala-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Leu-Ser-Arg-NH2
- Molecular formula: C152H252N44O42
- Molecular weight: 3367.9 g/mol
- CAS number: 863288-34-0
- Form: Lyophilised powder
- Purity: >99% (HPLC)
- Storage: 2-8°C, dark, upright, do not freeze. Keep sealed until use.
The starting point: GHRH(1-29)
Native human GHRH is a 44-amino-acid peptide, first isolated in 1982 from pancreatic tumours by the groups of Guillemin and Rivier. Researchers soon established that the N-terminal 29 residues, GHRH(1-29)-NH2, retain the receptor activity of the full-length peptide. This shorter fragment, sometimes called sermorelin, became the template for many later analogues.
The weakness of GHRH(1-29) as a research tool is its instability. In plasma it is rapidly cleaved by dipeptidyl peptidase-4 (DPP-4) between residues 2 and 3, and it is also vulnerable to oxidation and other enzymatic attack. Its reported half-life in circulation is measured in minutes, which limits the window available for observation in experimental systems.
What makes it "Mod GRF 1-29"
Modified GRF (1-29) addresses this instability through four amino acid substitutions to the native fragment:
- Position 2: L-alanine replaced with D-alanine, which hinders DPP-4 cleavage at the N-terminus
- Position 8: asparagine replaced with glutamine, reducing the tendency to deamidate
- Position 15: glycine replaced with alanine, which has been associated with greater helical stability
- Position 27: methionine replaced with leucine, removing an oxidation-prone residue
These four changes give the tetrasubstituted analogue its alternative name. The modified peptide is still a 29-residue C-terminal amide and is what most catalogues, including ours, list as CJC-1295 no DAC. You can see the full sequence above, with D-Ala at position 2, Gln at 8, Ala at 15 and Leu at 27.
What the DAC adds
CJC-1295 with DAC takes the same tetrasubstituted backbone and adds a further C-terminal lysine carrying a maleimidopropionic acid (MPA) group. DAC stands for Drug Affinity Complex, a technology developed by the Canadian company ConjuChem. The maleimide is a thiol-reactive group, and once in plasma it was designed to form a covalent bond with the free cysteine residue (Cys34) of serum albumin.
Albumin is abundant and long-lived, so a peptide anchored to it is protected from fast renal filtration and much enzymatic breakdown. Jetté and colleagues described this bioconjugation approach for GRF(1-29) in rats in 2005 and identified CJC-1295 as a long-lasting analogue. A 2006 study by Teichman and co-workers in the Journal of Clinical Endocrinology and Metabolism reported an estimated half-life of roughly six to eight days for CJC-1295 with DAC in adult volunteers.
Why the naming became muddled
Strictly, the code CJC-1295 was assigned by ConjuChem to the DAC-bearing molecule. Over time, the research supply market began using "CJC-1295 no DAC" as a convenient label for the tetrasubstituted backbone without the albumin-binding group. As a consequence, one code now covers two molecules. When reading a paper or a specification, it is worth checking the stated sequence, molecular weight and any mention of a maleimide or lysine extension rather than relying on the name alone.
Side-by-side comparison
Structure
No DAC: 29 residues, four substitutions relative to native GHRH(1-29), C-terminal amide. With DAC: the same 29 residues plus an extra lysine bearing a maleimidopropionyl group, giving a higher molecular weight.
Pharmacokinetics in the literature
No DAC: a half-life reported in the order of tens of minutes, longer than native GHRH(1-29) but still short. With DAC: a half-life reported in days because of albumin conjugation, as described by Teichman et al. (2006).
Signalling pattern
Because GHRH receptor signalling is pulsatile under physiological conditions, the duration of exposure matters. Short-acting analogues produce a brief, discrete period of receptor activation, whereas albumin-bound analogues produce a sustained signal. Researchers studying pulsatility and receptor desensitisation have regarded this distinction as a key design variable.
Development status
CJC-1295 with DAC entered early clinical studies in the mid-2000s, but development was discontinued and it has not been approved as a medicine. Mod GRF 1-29 has no marketing authorisation either. Material sold by Compound Cave is not a medicine and is intended only for in vitro and laboratory research.
How CJC-1295 no DAC relates to ipamorelin
GHRH analogues act at the GHRH receptor, while growth hormone-releasing peptides such as ipamorelin act at a different receptor, the growth hormone secretagogue receptor (GHS-R1a). The two pathways converge on the pituitary somatotroph but use separate signalling mechanisms. This is why the two classes are often discussed together in the literature, and why some catalogues list a combined vial. Our article on ipamorelin structure and selectivity covers the GHRP side in more detail, and tesamorelin offers a different approach to stabilising the GHRH sequence.
Handling and storage of the lyophilised material
As a lyophilised peptide, CJC-1295 no DAC is supplied as a dry powder in a sealed vial. We recommend storage at 2-8°C, away from light, kept upright and not frozen, and keeping the vial sealed until use. General guidance on handling dry peptide material is set out in our article on how to store lyophilised peptides, and our guide to reading a certificate of analysis explains how HPLC purity and mass spectrometry are used to confirm identity.
View CJC-1295 no DAC in the catalogue.
Frequently asked questions
Is CJC-1295 no DAC the same as Mod GRF 1-29?
In most supplier and research usage, yes. CJC-1295 no DAC refers to the tetrasubstituted GHRH(1-29) amide, which is also called modified GRF (1-29) or Mod GRF 1-29. It lacks the maleimide linker and lysine extension that define the DAC version.
What does DAC stand for?
DAC stands for Drug Affinity Complex. It describes a reactive maleimide group attached through a lysine residue, designed to form a covalent bond with circulating albumin. The concept was developed by ConjuChem, the company behind the original CJC-1295 work.
Why does the DAC version have a longer half-life?
Binding to albumin shields the peptide from rapid renal clearance and enzymatic degradation. A 2006 study by Teichman and colleagues reported an estimated half-life of several days for CJC-1295 with DAC, compared with minutes for native GHRH(1-29).
Which version does Compound Cave list?
The catalogue lists CJC-1295 no DAC as a lyophilised powder at >99% HPLC purity, both on its own and as a pre-blended vial with ipamorelin. Both are supplied strictly as laboratory research materials.
Are the two forms interchangeable in an experiment?
They should not be assumed to be. The pharmacokinetic profiles reported in the literature differ substantially, so a study design built around one form is not directly transferable to the other. Researchers usually specify the exact form in their methods.
References
- 1. Guillemin R, Brazeau P, Böhlen P, et al. Growth hormone-releasing factor from a human pancreatic tumor that caused acromegaly. Science. 1982;218:585-587.
- 2. Rivier J, Spiess J, Thorner M, Vale W. Characterization of a growth hormone-releasing factor from a human pancreatic islet tumour. Nature. 1982;300:276-278.
- 3. 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;146:3052-3058.
- 4. Teichman SL, Neale A, Lawrence B, et al. 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;91:799-805.
For laboratory research use only. Not for human or veterinary use. See our research use only policy.