GHRH and Its Role in GH Release

Growth hormone releasing hormone (GHRH) is secreted by the hypothalamus and acts on the pituitary somatotrophs to stimulate GH synthesis and release. Native GHRH has a plasma half-life of approximately 7 minutes due to rapid DPP-4 enzymatic cleavage at the alanine-2 position. CJC-1295 is a modified GHRH analog (29 amino acids) engineered to resist this cleavage while maintaining full receptor affinity.

DAC Technology: Albumin Binding for Extended Half-Life

The "DAC" in CJC-1295 DAC stands for Drug Affinity Complex. This modification involves a maleimidoproprionic acid (MPA) group covalently bound to lysine-30, which reacts with free thiol groups on endogenous albumin. Once injected, CJC-1295 DAC covalently binds to circulating albumin in plasma, creating a depot that slowly releases the active peptide over days. The result is a half-life of approximately 6–8 days — transforming a peptide that would normally last minutes into one that provides sustained GHRH signaling with once or twice-weekly dosing.

CJC-1295 Without DAC: Modified GRF(1-29)

CJC-1295 without the DAC modification (also known as Modified GRF 1-29 or Mod GRF) has a shorter half-life of approximately 30 minutes. It produces a sharper, more discrete GH pulse and is more suitable for research requiring acute GHRH stimulation. CJC-1295 DAC, by contrast, produces more sustained baseline elevation of GH and IGF-1. The choice between them depends on the research question — acute pulse vs. sustained elevation.

Stack with Ipamorelin

CJC-1295 (GHRH analog) and Ipamorelin (GHRP) act on different receptors in the GH axis. CJC-1295 provides the GHRH signal that primes somatotrophs for GH release. Ipamorelin provides the ghrelin receptor signal that triggers the actual pulse. Used together, they engage the GH axis at two different regulatory points, producing synergistic GH output. This is the most researched growth hormone secretagogue combination.

COA Standards for CJC-1295 DAC

CJC-1295 DAC is a 30-amino acid peptide with the MPA modification, giving it a MW of approximately 3,647 Da. The DAC modification must be confirmed by mass spectrometry — HPLC alone cannot distinguish CJC-1295 with DAC from Modified GRF 1-29. HPLC purity should be ≥98%. Researchers should request documentation that explicitly confirms the DAC modification is present.