Maple CJC-1295 is a synthetic growth hormone-releasing hormone (GHRH) analogue available in two distinct research formulations: with Drug Affinity Complex (DAC) and without DAC (also called Modified GRF 1-29). The DAC modification extends the peptide’s plasma half-life from approximately 30 minutes to 6-8 days by enabling covalent albumin binding, fundamentally altering its pharmacokinetic profile in preclinical models. Understanding these differences is critical for researchers selecting the appropriate variant for growth hormone axis investigations. Maple Research Labs supplies both CJC-1295 research peptides to Canadian laboratories with independent third-party COA verification.
What Is CJC-1295? Structure and Development Background
CJC-1295 is a 30-amino acid peptide analogue of GHRH(1-29) that was first characterized by ConjuChem Biotechnologies. The base sequence (Modified GRF 1-29) incorporates four amino acid substitutions at positions 2, 8, 15, and 27 to enhance resistance to dipeptidyl peptidase-IV (DPP-IV) enzymatic degradation. A 2006 study published in the Journal of Clinical Endocrinology & Metabolism by Teichman et al. demonstrated that these substitutions increased the peptide’s biological half-life from under 7 minutes (native GHRH) to approximately 30 minutes for Modified GRF 1-29 (n=31 healthy subjects, single ascending dose design).
The DAC-conjugated version adds a reactive lysine residue linked to a maleimidopropionic acid moiety. Once injected, this moiety forms a covalent bond with serum albumin, creating a long-circulating peptide-albumin conjugate. This bioconjugation technology was specifically designed to reduce injection frequency in research protocols while maintaining receptor activity at the GHRH receptor (GHRHR).
Pharmacokinetic Differences: Half-Life and Plasma Concentration Profiles
The most significant difference between CJC-1295 with DAC and without DAC lies in their pharmacokinetic profiles. Research data from Ionescu and Bhatt (2006), published in the Journal of Clinical Pharmacology, established the following parameters in healthy adult subjects:
CJC-1295 Without DAC (Modified GRF 1-29)
The non-DAC variant demonstrates a terminal half-life of approximately 30 minutes. Peak plasma concentrations occur within 15-30 minutes of subcutaneous administration. GH elevation follows a pulsatile pattern, with peak GH levels observed 15-30 minutes post-administration and returning to baseline within 2-3 hours. In a dose-escalation study (30, 60, 90, and 125 mcg/kg), mean peak GH levels increased in a dose-dependent manner, with the 125 mcg/kg group showing a 7.5-fold increase over baseline (p<0.001).
CJC-1295 With DAC
The DAC-conjugated variant shows a dramatically extended half-life of 6-8 days. The albumin binding results in sustained, non-pulsatile GH elevation. Teichman et al. (2006) reported that a single 60 mcg/kg dose produced sustained IGF-1 elevation lasting 9-11 days (mean increase of 1.5-fold to 3-fold over baseline across the observation period, n=31). Notably, GH levels remained elevated above baseline for 6 or more days after a single administration, a profile fundamentally different from the acute pulsatile pattern seen with the non-DAC variant.
GH Secretion Patterns: Pulsatile vs Sustained Elevation
The distinction between pulsatile and sustained GH release is not merely academic. Natural GH secretion follows a pulsatile pattern regulated by hypothalamic GHRH and somatostatin interplay. Research suggests that GH pulse characteristics, including amplitude, frequency, and duration, influence downstream signaling differently than tonic elevation.
A 2005 study by Veldhuis et al. in the American Journal of Physiology demonstrated that pulsatile GH administration in GH-deficient animal models produced 1.4-fold greater IGF-1 mRNA expression in hepatic tissue compared to continuous infusion at identical total doses (n=18 rats, p<0.05). This finding has led researchers to hypothesize that Modified GRF 1-29 (without DAC) may more closely mimic endogenous GH physiology in experimental settings, while the DAC variant may be better suited for studying sustained GH axis activation.
Receptor Binding and Mechanism of Action
Both variants act as GHRHR agonists. The GHRH receptor is a class B G-protein coupled receptor (GPCR) expressed primarily on anterior pituitary somatotroph cells. Upon binding, both CJC-1295 variants activate adenylyl cyclase via Gs protein coupling, increasing intracellular cAMP and triggering GH release from preformed secretory granules.
The key mechanistic difference is not at the receptor level but in plasma availability. The DAC version maintains receptor-activating concentrations for days rather than minutes, resulting in continuous somatotroph stimulation. Research by Alba et al. (2006) in the Journal of Clinical Endocrinology & Metabolism confirmed that CJC-1295 with DAC produced dose-dependent increases in mean 24-hour GH concentrations of 1.7-fold (30 mcg/kg) to 2.9-fold (60 mcg/kg) above baseline, sustained over multiple days (n=21).
Research Applications and Protocol Considerations
The choice between CJC-1295 variants depends on the specific research question. Modified GRF 1-29 (without DAC) is typically preferred for studies requiring acute GH stimulation tests, investigating pulsatile GH dynamics, short-duration pharmacological challenges, and combination studies with GHRP-class peptides where precise timing control is needed.
CJC-1295 with DAC is generally selected for studies examining sustained GH axis activation, longer-duration metabolic studies where daily injections are impractical, IGF-1 elevation kinetics over extended timeframes, and chronic administration models examining body composition endpoints.
A 2008 pharmacokinetic modeling study by Ferdinandi et al. in the Journal of Pharmaceutical Sciences estimated that CJC-1295 with DAC achieved greater than 95% albumin binding within 15 minutes of subcutaneous injection in a rat model (n=24), confirming rapid bioconjugation as the mechanism underlying its extended duration of action.
Stability, Storage, and Purity Verification
Both CJC-1295 variants are susceptible to degradation through oxidation and hydrolysis. Research-grade material should be stored lyophilized at -20°C. Once reconstituted, both variants should be refrigerated at 2-8°C and used within 14-21 days. The DAC moiety does not significantly alter storage requirements for the lyophilized form but may introduce additional degradation pathways in solution due to the maleimide linker’s susceptibility to hydrolysis.
HPLC purity verification is essential for both variants. The DAC conjugate produces a distinct chromatographic profile with a longer retention time due to increased hydrophobicity from the albumin-binding moiety. At Maple Research Labs, all peptide products undergo independent third-party testing by Janoshik Analytical to verify purity, identity, and composition. Researchers can review our COA interpretation guide for detailed information on reading analytical certificates.
Key Research Findings
CJC-1295 without DAC has a half-life of approximately 30 minutes versus 6-8 days for the DAC variant (Teichman et al., 2006, JCEM). Single-dose CJC-1295 with DAC at 60 mcg/kg sustained IGF-1 elevation for 9-11 days in healthy subjects (n=31). Pulsatile GH delivery produced 1.4-fold greater hepatic IGF-1 mRNA than continuous infusion at equivalent doses in rat models (Veldhuis et al., 2005). DAC bioconjugation achieves greater than 95% albumin binding within 15 minutes of administration (Ferdinandi et al., 2008). Both variants activate the same GHRHR pathway; the difference is pharmacokinetic, not pharmacodynamic.
For researchers investigating growth hormone axis physiology, the choice between CJC-1295 variants represents a fundamental experimental design decision. Maple Research Labs provides both formulations with batch-specific Certificates of Analysis for Canadian research institutions. Browse our full research peptide catalogue or review our documentation standards for more information on our quality verification process.
Researchers transitioning from US-based suppliers may also find our guide on Canadian peptide supplier alternatives useful for understanding domestic sourcing advantages including same-day Canadian shipping and simplified customs clearance.
For research purposes only. Not for human consumption. Not for diagnostic or therapeutic use.