What Is CJC-1295? DAC vs No DAC (Mod GRF 1-29) Explained
CJC-1295 comes in two versions that behave very differently: with DAC it lasts about a week, without DAC (Mod GRF 1-29) it lasts about 30 minutes. Here is what CJC-1295 is and how the two compare.
What is CJC-1295?
CJC-1295 is a synthetic analogue of growth hormone releasing hormone (GHRH). It was developed by the Canadian company ConjuChem in the early 2000s. It acts at the GHRH receptor in the pituitary, the same receptor the body's own GHRH uses. The name now covers two different peptides, which is where most confusion comes from.
| CJC-1295 No DAC | CJC-1295 with DAC | |
|---|---|---|
| Also called | Mod GRF 1-29 | CJC-1295 DAC |
| Length | 29 amino acids | 29 + a modified lysine |
| Albumin binding | No | Yes |
| Half-life | About 30 minutes | About 6 to 8 days |
| Our vials | 10mg | 5mg and 10mg |
- Natural GHRH~7 min
- CJC-1295 No DAC~30 min
- CJC-1295 DAC~6 to 8 days
Log scale. The DAC version lasts hundreds of times longer because it binds albumin.
The four substitutions (Mod GRF 1-29)
Natural GHRH is 44 amino acids, but only the first 29 are needed for activity. That fragment breaks down within minutes, so four amino acids were swapped to protect it:
| Position | Natural | Swapped to | Why |
|---|---|---|---|
| 2 | Alanine | D-Alanine | Blocks the main cutting enzyme (DPP-4) |
| 8 | Asparagine | Glutamine | Improves chemical stability |
| 15 | Glycine | Alanine | Improves stability |
| 27 | Methionine | Leucine | Prevents oxidation |
That modified 29-amino-acid peptide is Mod GRF 1-29, sold as CJC-1295 No DAC.
What DAC adds
DAC stands for drug affinity complex. It is a lysine with a maleimide group added at the end of the chain. Once in blood, that group bonds to albumin, the most common blood protein. Riding on albumin protects the peptide from enzymes and the kidneys, which is why a 2006 human study measured a half-life of roughly six to eight days.
Which one is used in research?
The choice comes down to the signal a study wants: No DAC gives a short pulse similar to natural GHRH, while DAC gives sustained exposure. CJC-1295 No DAC is also the version in our CJC-1295 + Ipamorelin blend; see what is Ipamorelin for its partner.
Further reading
- CJC-1295 vs Ipamorelin vs Tesamorelin
- What is Ipamorelin?
- What is Tesamorelin?
- How to reconstitute peptides
For laboratory research use only. Not for human consumption. Not medical or legal advice.
