Encyclopedia

CJC-1295 with DAC is a long-acting analog of growth-hormone-releasing hormone (GHRH) fragment (1-29), chemically modified with a Drug Affinity Complex (DAC) that covalently binds circulating albumin. This extends its half-life from minutes to approximately 6-8 days, allowing once- or twice-weekly dosing with sustained GH and IGF-1 elevation. It is a distinct entry from CJC-1295 (no DAC) / Modified GRF(1-29), which shares the same peptide backbone but clears in about 30 minutes.

CJC-1295 is built on the same tetrasubstituted GHRH(1-29) backbone as the no-DAC (Modified GRF) version, but carries an added maleimidopropionyl-linked DAC group. After subcutaneous injection, the maleimide reacts with the free thiol on cysteine-34 of circulating albumin, forming a stable covalent thioether bond. Because albumin itself has a plasma half-life of roughly 19 days, this conjugation shields the peptide from renal filtration and proteolytic clearance, extending its own half-life to about 6-8 days. A single dose has been shown in a phase I randomized, placebo-controlled trial (Teichman et al., 2006) to produce dose-dependent 2- to 10-fold GH elevations and 1.5- to 3-fold IGF-1 elevations lasting 9-11 days; with repeated dosing, IGF-1 remained elevated for up to 28 days. It is not FDA-approved and has no approved clinical indication; it is sold as a research chemical.

Mechanism of Action

Binds the GHRH receptor (GHRHR) on pituitary somatotrophs to stimulate GH synthesis and release, identical in principle to the no-DAC form. The DAC modification covalently conjugates the peptide to serum albumin via cysteine-34, adopting albumin's slow clearance kinetics and converting a normally pulsatile, short-acting GHRH signal into a sustained, days-long elevation of GH and downstream IGF-1.