CJC-1295 No DAC

What Is CJC-1295 No DAC?

CJC-1295 No DAC is a synthetic analogue of the first 29 amino acids of human growth-hormone-releasing hormone (GHRH 1-29, the sermorelin sequence), tetra-substituted at positions 2, 8, 15, and 27 to resist proteolysis. The substitutions are D-Ala at position 2 (the DPP-IV cleavage site), Gln at 8 (trypsin resistance), Ala at 15 (chymotrypsin and endopeptidase resistance), and Leu at 27 (resistance to methionine oxidation). The result is a plasma half-life of roughly 30 minutes, against about 7 minutes for sermorelin and native GHRH.

The molecule binds the GHRH receptor on pituitary somatotrophs and triggers a discrete, pulsatile release of growth hormone. Each exposure produces a sharp GH rise that decays within one to two hours, reproducing the body's own pulsatile GH rhythm at higher amplitude. The No DAC designation is the critical distinction from the full CJC-1295 molecule, which carries a Drug Affinity Complex linker that covalently binds serum albumin and extends the half-life to 6 to 8 days with continuous rather than pulsatile elevation. Without the DAC group the molecule is functionally identical to what older literature calls modified GRF 1-29. Pulsatility matters because somatotroph signalling and hepatic IGF-1 production are tuned to pulse patterns; continuous GH exposure is associated with greater insulin resistance and receptor downregulation in the published comparisons.