CJC-1295 with DAC vs without DAC — and which one this is
This is the form without DAC. The two forms are separated by 279.3 Da: 3367.9 Da for the DAC-free peptide supplied here, 3647.2 Da for CJC-1295 with DAC, the difference being the Drug Affinity Complex — a thirtieth lysine residue bearing a maleimidopropionic acid linker — which binds covalently to cysteine-34 of serum albumin.
That covalent bond is why the DAC form's duration tracks albumin turnover — around nineteen days — while this one clears in roughly thirty minutes. Mass, not name, is the reliable discriminator: PubChem's own record for the DAC-free peptide carries both a with-DAC and a no-DAC synonym, and suppliers inherit that confusion.
We do not supply the DAC form. A short half-life is a design choice rather than a defect — a compound clearing in thirty minutes models a brief, physiological-like pulse more closely than one producing continuous exposure for days, and which is appropriate depends entirely on the research question.
- CJC-1295 without DAC, also called Modified GRF (1-29) — 3367.9 Da, C152H252N44O42, PubChem CID 56841945, CAS 863288-34-0, no albumin binding, clearance in roughly thirty minutes. This is what the vial contains.
- CJC-1295 with DAC — 3647.2 Da, C165H269N47O46, PubChem CID 91971820, covalently albumin-bound at Cys34, duration measured in days. Not supplied here.
- Sermorelin, native GRF(1-29) — 3357.9 Da, C149H246N44O42S: 10.0 Da lighter, and the only one of the three whose formula contains sulfur, because the substitution set removes the methionine. Not supplied here.
