Source comparison
What's the Half-Life of CJC-1295? (With vs Without DAC)
The most important thing to understand about what's the half-life of CJC-1295 is that there are actually two different compounds sharing the same base name. And their pharmacokinetics couldn't be more different. CJC-1295 with DAC (Drug Affinity Complex) has a
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- The most important thing to understand about what's the half-life of CJC-1295 is that there are actually two different compounds sharing the same base name. And their pharmacokinetics couldn't be more different. CJC-1295 with DAC (Drug Affinity Complex) has a half-life of approximately 6–8 days, allowing weekly or twice-weekly dosing. The modified version. Often called 'CJC-1295 without DAC' or simply 'Modified GRF(1-29)'. Has a half-life of less than 30 minutes, requiring multiple daily administrations for sustained GH pulse elevation. The DAC molecule binds the peptide to serum albumin, extending circulation time by preventing enzymatic degradation that would otherwise occur within minutes.
- Our team has worked with researchers across metabolic health, performance optimization, and regenerative medicine protocols for years. The confusion around CJC-1295 half-life is one of the most common sourcing errors we see. Labs ordering the wrong variant because they assumed 'CJC-1295' meant a single compound with a single dosing schedule.
- What's the half-life of CJC-1295?
- CJC-1295 with DAC has a terminal half-life of approximately 6–8 days, meaning it takes roughly one week for plasma concentrations to drop by 50% after a single injection. The non-DAC version (Modified GRF 1-29) has a half-life of under 30 minutes due to rapid enzymatic cleavage by dipeptidyl peptidase-4 (DPP-4). This difference fundamentally changes dosing frequency: the DAC version sustains elevated growth hormone levels across multiple days, while the non-DAC variant produces acute GH pulses that dissipate within hours.
- Here's what most guides overlook: the extended half-life of CJC-1295 with DAC wasn't the primary design goal. It was a mechanism to prevent the peptide's near-instant degradation by DPP-4 enzymes in plasma. Growth hormone-releasing hormone (GHRH) analogs like native GHRH(1-44) or unmodified GRF(1-29) are cleaved at the Ala2 position within minutes of entering circulation. The Drug Affinity Complex. Four lysine molecules covalently bonded to the peptide's structure. Binds to serum albumin and physically shields the cleavage site from DPP-4 access. What you're dosing isn't just a longer-acting peptide; it's a peptide-albumin conjugate that circulates as a bound complex.