What Is CJC-1295 (No DAC)?
CJC-1295 without DAC — also known as Modified GRF (1-29) or Mod GRF 1-29 — is a stabilised synthetic analogue of the first 29 amino acids of endogenous GHRH. Four amino acid substitutions at positions 2, 8, 15, and 27 confer resistance to dipeptidyl peptidase-IV (DPP-IV) cleavage, extending its active half-life from ~2 minutes (native GHRH) to ~30 minutes. This is the version used in most GHRH/GHRP combination research protocols.
Note: CJC-1295 with DAC uses a drug affinity complex to bind albumin, producing a half-life of 6–8 days. The no-DAC version is preferred when researchers wish to maintain pulsatile GH release patterns rather than sustained elevation.
Mechanism of Action
CJC-1295 (no DAC) binds GHRHR on anterior pituitary somatotrophs, stimulating a single, well-defined GH pulse within 15–30 minutes of administration. Because it does not persist systemically, the natural GH feedback loop is preserved.
Research Applications
- GH pulse studies: Provides a reproducible, dose-dependent GH stimulus for pituitary function research
- Combination protocols: The GHRH + GHRP combination is the most studied peptide stack in GH axis research — CJC-1295 (no DAC) + Ipamorelin or GHRP-6 produces 4–10× greater GH AUC than either alone
- Body composition: Research in GH-deficient adults shows improvements in lean mass and fat distribution over 12-week periods
- Safety: No evidence of pituitary desensitisation with pulsatile dosing protocols
Research Notes
CJC-1295 (no DAC) is best administered immediately before sleep to coincide with the natural nocturnal GH surge. Store lyophilised peptide at −20°C.
Related compounds: Ipamorelin, Sermorelin, GHRP-6, Hexarelin.