Growth hormone axis
CJC-1295 With DAC vs Without DAC: Research Comparison
Both are analogues of the first 29 amino acids of GHRH with four amino-acid substitutions. The difference is the drug affinity complex (DAC): a linker that bonds CJC-1295 with DAC to albumin in the blood, so it circulates for days. The version without DAC, also sold as Modified GRF 1-29, has no linker.
Side-by-side comparison
| Attribute | CJC-1295 with DAC | CJC-1295 without DAC (Mod GRF 1-29) |
|---|---|---|
| Structure | GHRH(1-29) with four substitutions, plus a lysine carrying the DAC linker | GHRH(1-29) with four substitutions, no linker |
| Albumin binding | Yes, bonds to albumin in the blood | No |
| Human half-life | About six to eight days (Teichman et al., 2006) | No human half-life reported |
| Human data | Short studies in healthy adults measuring hormone levels | No published controlled human studies |
| Licensed status | Not approved by the FDA or EMA | Not approved by the FDA or EMA |
Detailed analysis
CJC-1295 with DAC was developed by ConjuChem. The DAC linker bonds the peptide to albumin, a blood protein. In rats it was found attached to albumin and was still in plasma beyond 72 hours (Jetté et al., 2005). In two randomised, placebo-controlled trials in healthy adults, a single administration raised growth hormone for six days or more and IGF-1 for 9 to 11 days (Teichman et al., 2006). A follow-up study in a small group of healthy young men found that growth hormone pulses were preserved while levels between pulses rose.
CJC-1295 without DAC has the same four substitutions but no linker, so it is not expected to stay in circulation for days. In the developer's papers the name CJC-1295 referred to the DAC compound, so human studies of CJC-1295 describe the DAC version. A 2026 review described the version without DAC as essentially uncharacterised in peer-reviewed human research (Dominikowski et al., 2026).
Results from one version cannot be assumed to apply to the other.
Key differences
- ·The DAC version bonds to albumin and circulates for days; the version without DAC does not.
- ·Published human studies of CJC-1295 describe the DAC version only.
- ·In a small study the DAC version preserved growth hormone pulses while raising levels between them.
- ·The version without DAC has no reported human half-life.
Research summary
CJC-1295 with DAC has rat studies (Jetté et al., 2005) and short hormone-level studies in healthy adults (Teichman et al., 2006). CJC-1295 without DAC has scarce published data of its own, so its expected action is inferred from related GHRH analogues. Long-term safety is unknown for both. Supplied for laboratory research use only.