CJC-1295 is a synthetic analogue of growth hormone-releasing hormone (GHRH), the endogenous hypothalamic peptide that drives pituitary GH secretion. Native GHRH has a plasma half-life of less than 10 minutes, rapidly inactivated by dipeptidyl peptidase IV (DPP-IV). CJC-1295 was developed by ConjuChem to overcome this limitation through two key modifications:
- DPP-IV resistance, amino acid substitutions at positions 2 and 8 protect the peptide from enzymatic cleavage
- Drug Affinity Complex (DAC) technology, a reactive lysine residue allows covalent binding to endogenous albumin after injection, extending the half-life to approximately 6–8 days
The result is a GHRH analogue that produces sustained GHRH signalling from a single weekly injection. CJC-1295 without DAC (also called Modified GRF 1-29 or Mod-GRF) retains the DPP-IV-resistant modifications but lacks the albumin-binding DAC, giving a half-life of approximately 30 minutes and producing a more physiological pulsatile GH pattern.
DAC vs No-DAC: Which for Research? CJC-1295 with DAC produces sustained GH elevation (constant signal, once-weekly dosing). CJC-1295 without DAC produces sharp GH pulses resembling physiological pulsatility (multiple daily doses required). The research question determines the choice: sustained GH effects → use DAC; pulsatile GH physiology → use no-DAC with Ipamorelin.