Source comparison
DAC vs No DAC: Why the Distinction Exists
The Drug Affinity Complex (DAC) is a synthetic chemical moiety that binds non-covalently to serum albumin, dramatically extending the half-life of conjugated peptides from minutes to days. CJC-1295 with DAC. Sometimes called CJC-1295 DAC or simply CJC-1295 wit
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- The Drug Affinity Complex (DAC) is a synthetic chemical moiety that binds non-covalently to serum albumin, dramatically extending the half-life of conjugated peptides from minutes to days. CJC-1295 with DAC. Sometimes called CJC-1295 DAC or simply CJC-1295 without the 'no DAC' qualifier. Has a half-life of 6–8 days, allowing for once-weekly administration and sustained elevation of growth hormone and IGF-1 levels. CJC-1295 no DAC, by contrast, retains the 30-minute half-life of the base peptide, requiring multiple daily administrations to maintain pulsatile GH release that mimics endogenous secretory patterns.
- The naming problem arose during clinical development. ConjuChem Biotechnologies originally developed CJC-1295 with DAC for therapeutic use in growth hormone deficiency. The DAC conjugation was the defining feature. When researchers wanted the same GHRH analog without the DAC extension for studies requiring physiological GH pulsatility rather than sustained elevation, they needed a way to distinguish it. Some vendors called it CJC-1295 no DAC. Others adopted Mod GRF 1-29, referencing the modification of native GRF(1-29) without implying DAC conjugation. Both names stuck, creating the current nomenclature overlap.
- Pharmacologically, the difference matters. CJC-1295 with DAC produces supraphysiological, sustained GH elevation. Useful for studying chronic GH exposure effects but not for replicating normal pulsatile secretion. Mod GRF 1-29 and CJC-1295 no DAC produce sharp GH peaks 15–30 minutes post-administration that return to baseline within 90–120 minutes, matching the 3–4 hour ultradian rhythm of endogenous GH secretion. Research protocols examining GH pulse amplitude, frequency modulation, or circadian rhythmicity require the no-DAC version. Confusion between the two leads to fundamentally different experimental outcomes. A researcher expecting pulsatile release who receives DAC-conjugated peptide will observe blunted peak amplitude and elevated baseline GH instead.