CJC-1295 DAC: Complete Research Guide & Mechanism Overview

CJC-1295 with DAC (also written CJC1295 DAC) is a synthetic analogue of growth hormone releasing hormone (GHRH) engineered to resist enzymatic degradation and bind serum albumin, extending its half-life from under 10 minutes to approximately 6-8 days in published human pharmacokinetic studies. The DAC (Drug Affinity Complex) technology - a maleimidopropionic acid linker enabling covalent albumin binding - represents the same half-life extension strategy used in semaglutide, applied here to the GHRH axis rather than the GLP-1 axis. The result is a GHRH analogue that produces sustained pituitary GH secretion over days from a single administration in published research models.

This article covers the molecular structure of CJC-1295+DAC (CJC1295), its mechanism of action at the GHRH receptor, its pharmacokinetic profile relative to native GHRH, and its research combination rationale with ipamorelin. All content is for research purposes only. Not for human consumption.

What Is CJC-1295 with DAC (CJC1295)?

CJC-1295+DAC is a synthetic analogue of growth hormone releasing hormone (GHRH), the hypothalamic peptide that stimulates GH synthesis and secretion from anterior pituitary somatotroph cells. Endogenous GHRH is a 44-amino acid peptide, but its biological activity resides predominantly in the first 29 amino acids (GHRH 1-29). CJC-1295 is based on this active fragment, with four strategic amino acid substitutions conferring DPP-4 resistance, plus the Drug Affinity Complex (DAC) technology adding a maleimidopropionic acid linker at a specific lysine residue that enables covalent albumin binding in vivo.

The result is a GHRH analogue that maintains full GHRH receptor (GHRHr) agonist activity while exhibiting a dramatically extended pharmacokinetic profile - which means CJC-1295+DAC (also written CJC1295) can be used to study sustained GHRH receptor activation in research models where the ~7-minute half-life of native GHRH would make continuous GH axis stimulation logistically impractical.

Molecular Profile

CJC-1295 Mechanism of Action: GHRH Receptor Agonism

CJC-1295+DAC acts as a full agonist at the GHRH receptor (GHRHr), a Gs-coupled GPCR expressed on anterior pituitary somatotroph cells and a subset of hypothalamic neurons. Receptor binding activates adenylyl cyclase, elevates intracellular cAMP, and activates protein kinase A - leading to both acute GH secretion and longer-term upregulation of GH gene expression and pituitary somatotroph cell proliferation in published animal models.

The physiological consequence is stimulation of GH synthesis and secretion from somatotroph cells - which then drives downstream IGF-1 production in the liver, the primary mediator of GH's anabolic and metabolic effects in peripheral tissue. Because CJC-1295+DAC's extended half-life maintains sustained GHRH receptor occupancy over days, the published pharmacological effect is a prolonged elevation of GH and IGF-1 rather than the discrete pulse produced by shorter-acting GHRH analogues or GHRPs such as ipamorelin.

The DAC Technology: How Albumin Binding Extends Half-Life

The Drug Affinity Complex (DAC) technology at the core of CJC-1295+DAC's pharmacokinetic profile involves a maleimidopropionic acid (MPA) linker attached to the Lys33 residue within the CJC-1295 backbone. In vivo, this linker forms a covalent thioether bond with the free thiol group on Cys34 of serum albumin - binding CJC-1295 directly to the most abundant plasma protein in the body.

Serum albumin has a half-life of approximately 19 days in humans. By covalently binding to albumin, CJC-1295+DAC effectively inherits albumin's pharmacokinetic stability - which means it is protected from renal filtration (albumin is too large to filter) and from the DPP-4 enzyme-mediated degradation that rapidly clears native GHRH. The result, as demonstrated by Jette L et al. (2005), is a half-life of up to 19 days in rodent models and 6-8 days in published human pharmacokinetic data.

This is the same conceptual strategy used in semaglutide, where a C18 fatty acid chain achieves reversible (non-covalent) albumin binding to extend the GLP-1 analogue's half-life to ~7 days. The key distinction is that DAC produces covalent albumin binding, while semaglutide's fatty acid chain produces reversible non-covalent binding - which means CJC-1295+DAC maintains a more stable, less variable plasma level than semaglutide's reversible binding approach.

CJC-1295 vs Native GHRH: Pharmacokinetic Comparison

CJC-1295 and Ipamorelin: Dual-Axis GH Research

The research combination of CJC-1295+DAC (CJC1295) and ipamorelin is mechanistically distinct from simply using two GH secretagogues together. The compounds target entirely different receptors in the GH axis:

• CJC-1295+DAC activates the GHRH receptor (GHRHr) on pituitary somatotrophs - the primary stimulatory signal driving GH synthesis and sustained secretion.
• Ipamorelin activates GHSR-1a (the ghrelin receptor) - amplifying the GH pulse response to GHRH stimulation while simultaneously suppressing somatostatin tone in the hypothalamus.

The somatostatin suppression produced by ipamorelin's GHSR-1a activation is particularly important here - somatostatin is the primary inhibitory brake on GH release, and its suppression effectively increases the amplitude of GH pulses triggered by CJC-1295's GHRH receptor activation. The combination therefore targets both the accelerator (GHRH receptor) and the brake (somatostatin suppression via GHSR-1a) of the GH secretion axis simultaneously - which is why published GH research increasingly uses this combination to study maximum pituitary GH secretory capacity rather than either compound alone.

Key Published Research

Jette L et al. (2005) - DAC Technology Proof of Concept

Published in Endocrinology (PMID: 15705778), this study by the ConjuChem team who developed the DAC technology characterised the pharmacokinetics of CJC-1295+DAC in rats and monkeys. In rats, the compound demonstrated a half-life of up to 19 days - the foundational pharmacokinetic data establishing that DAC-mediated albumin binding could translate GHRH's receptor potency into a long-acting research tool.

Teichman SL et al. (2006) - Human Pharmacokinetic Data

Published in the Journal of Clinical Endocrinology & Metabolism (PMID: 16352683), this Phase I/II trial administered CJC-1295+DAC to healthy adult volunteers and measured GH and IGF-1 responses over time. The study confirmed a half-life of approximately 6-8 days in humans and demonstrated dose-dependent increases in mean 24-hour GH concentration - the first published human evidence that the DAC pharmacokinetic extension translated from animal models to human subjects.

Frequently Asked Questions

Summary

CJC-1295+DAC (CJC1295, CAS: 863288-34-0) is a full GHRH receptor agonist engineered for sustained pharmacological activity, converting what is effectively a seconds-to-minutes endogenous hormone signal into a days-long research tool. Its DAC-mediated albumin binding extends the half-life from under 10 minutes (native GHRH) to 6-8 days in human pharmacokinetic studies - the longest-acting GHRH analogue in the published research chemical literature.

The mechanistic rationale for combining CJC-1295+DAC with ipamorelin is well-established in published literature: the two compounds target complementary arms of the GH secretion axis - GHRH receptor stimulation and somatostatin suppression - producing synergistic GH release that neither compound achieves alone. Both are available from Pure Grade Labs at research grade with batch-specific COA documentation, for laboratory research only. Not for human consumption.

References

1. Jette L et al. (2005). hGRF1-29-Albumin Bioconjugates Activate the GRF Receptor on the Anterior Pituitary in Rats: A Prolonged Hormone Half-Life. Endocrinology. PMID: 15705778. DOI: 10.1210/en.2004-0842.
2. Teichman SL et al. (2006). Prolonged Stimulation of Growth Hormone (GH) and Insulin-Like Growth Factor I Secretion by CJC-1295, a Long-Acting Analog of GH-Releasing Hormone. Journal of Clinical Endocrinology & Metabolism. PMID: 16352683. DOI: 10.1210/jc.2005-1500.
3. Raun K et al. (1998). Ipamorelin, the first selective growth hormone secretagogue. European Journal of Endocrinology. PMID: 9849822. DOI: 10.1530/eje.0.1390552.
4. Ghigo E et al. (1997). Growth hormone-releasing peptides. European Journal of Endocrinology. PMID: 9405023.