Maple CJC-1295 is a synthetic 30-amino-acid analog of growth hormone-releasing hormone (GHRH) engineered with four strategic amino acid substitutions that confer resistance to dipeptidyl peptidase IV (DPP-IV) degradation, extending its biological half-life from minutes to hours or days depending on the formulation variant. Preclinical and early clinical data demonstrate that CJC-1295 produces sustained, dose-dependent elevations in growth hormone (GH) and insulin-like growth factor 1 (IGF-1), making it one of the most pharmacologically characterized GHRH analogs in the research literature.
The development of CJC-1295 emerged from a broader effort to overcome the fundamental pharmacokinetic limitation of native GHRH(1-44) and its truncated form GHRH(1-29), both of which are rapidly cleaved by DPP-IV at the Ala2-Asp3 bond within minutes of administration. This enzymatic vulnerability renders native GHRH impractical for sustained GH axis research. CJC-1295 addresses this problem through molecular engineering that preserves receptor binding affinity while dramatically improving metabolic stability.
Molecular Design and DPP-IV Resistance
CJC-1295 is based on the GHRH(1-29) scaffold with four amino acid substitutions at positions 2, 8, 15, and 27. The substitution at position 2 (Ala to D-Ala) is the most critical modification, directly blocking the DPP-IV cleavage site that destroys native GHRH within 5 to 7 minutes in circulation. The remaining three substitutions (Gln8 to Ala, Ala15 to Leu, Met27 to Leu) enhance overall proteolytic resistance and receptor binding stability without compromising the peptide’s ability to activate the GHRH receptor (GHRH-R) on anterior pituitary somatotrophs.
This tetrasubstituted analog, sometimes referred to as modified GRF(1-29), retains full agonist activity at the GHRH receptor while achieving a plasma half-life of approximately 30 minutes in its unmodified form. The pharmacological profile was first characterized by Iovino and colleagues in early structure-activity studies that mapped the relationship between GHRH sequence modifications and biological potency in rodent models.
The DAC Modification: Albumin Bioconjugation Technology
The most pharmacologically significant advance in CJC-1295 research was the addition of a Drug Affinity Complex (DAC), a reactive maleimidopropionic acid moiety attached to a lysine residue at the C-terminus. This modification enables the peptide to form a covalent bond with the Cys34 residue on circulating serum albumin after subcutaneous injection. The albumin-bound complex is protected from renal filtration and enzymatic degradation, extending the effective half-life to approximately 6 to 8 days in preclinical models.
The landmark characterization of this bioconjugation mechanism was published by Jetté and colleagues (2005) in Endocrinology. Their work demonstrated that CJC-1295 with DAC produced a 4-fold increase in GH area under the curve over a 2-hour period compared with unmodified GHRH(1-29) in rat models. Western blot analysis confirmed that the peptide appeared on the albumin band within 15 minutes of injection and remained detectable beyond 72 hours, validating the in vivo bioconjugation hypothesis (Jetté et al., Endocrinology, 2005).
This pharmacokinetic distinction between the DAC and non-DAC variants is critical for research design. The non-DAC form (modified GRF 1-29) produces acute, pulsatile GH release patterns that more closely mimic physiological GHRH signaling. The DAC form produces a sustained, tonic elevation of GH that resembles continuous GHRH infusion. Researchers studying GH pulse dynamics versus sustained GH exposure use these two variants to model fundamentally different endocrine scenarios. For a detailed comparison of both forms, see our CJC-1295 DAC vs No DAC research comparison.
GHRH Receptor Pharmacology and Downstream Signaling
CJC-1295 exerts its effects through direct agonism of the GHRH receptor, a class B G protein-coupled receptor (GPCR) expressed primarily on somatotroph cells of the anterior pituitary. Receptor binding activates adenylyl cyclase via Gs-alpha coupling, increasing intracellular cyclic adenosine monophosphate (cAMP) concentrations. This triggers protein kinase A (PKA) activation, which drives GH gene transcription through phosphorylation of the cAMP response element-binding protein (CREB).
The cAMP/PKA/CREB pathway also promotes somatotroph proliferation and survival, which is relevant for research models examining pituitary function under chronic GHRH stimulation. Unlike growth hormone secretagogues (GHS) that act through the ghrelin receptor (GHS-R1a), CJC-1295 does not stimulate appetite signaling, cortisol release, or prolactin secretion at physiologically relevant concentrations. This receptor selectivity makes CJC-1295 a cleaner pharmacological tool for isolating GHRH-specific effects on the GH/IGF-1 axis.
The distinction between GHRH receptor agonists like CJC-1295 and ghrelin receptor agonists like ipamorelin is a foundational concept in growth hormone research. Our Ipamorelin vs CJC-1295 comparison explores the complementary receptor pharmacology of these two peptide classes in detail.
Preclinical Evidence: GH and IGF-1 Axis Activation
The most robust preclinical dataset for CJC-1295 comes from the GHRH knockout (GHRH-KO) mouse model. Alba and colleagues (2006) published in the American Journal of Physiology that once-daily administration of CJC-1295 normalized growth parameters in GHRH-KO mice, which otherwise exhibit severe GH deficiency and dwarfism. Treated animals showed significant increases in body weight, body length, and nose-to-anus measurements compared to vehicle-treated GHRH-KO controls, demonstrating that the peptide could functionally replace endogenous GHRH signaling (Alba et al., American Journal of Physiology: Endocrinology and Metabolism, 2006).
Subsequent work by Ionescu and Chen (2006) in the Journal of Clinical Endocrinology and Metabolism examined CJC-1295 with DAC in healthy human subjects, reporting dose-dependent increases in mean GH concentrations of 2 to 10-fold above baseline, with IGF-1 elevations of 1.5 to 3-fold that persisted for 6 to 14 days following a single subcutaneous injection. These pharmacodynamic data confirmed that the albumin bioconjugation strategy successfully translated from rodent models to larger organisms.
The sustained IGF-1 elevation observed with CJC-1295 DAC is particularly relevant for research into the somatotropic axis and its relationship with tissue remodeling, metabolic regulation, and cellular proliferation. IGF-1 acts as the primary mediator of many GH-dependent effects through activation of the IGF-1 receptor (IGF-1R) and downstream PI3K/Akt and MAPK/ERK signaling cascades.
Synergistic Research Models: CJC-1295 and Ipamorelin
One of the most studied peptide combinations in growth hormone research pairs CJC-1295 (non-DAC) with ipamorelin, a selective GHS-R1a agonist. The pharmacological rationale is straightforward: GHRH primes somatotrophs for GH release while ghrelin receptor agonism triggers the release itself. Preclinical data from Bowers (1998) and subsequent combination studies show that co-administration of GHRH analogs with GHS compounds produces GH release that exceeds the additive sum of either agent alone, suggesting true pharmacological synergism at the pituitary level.
This synergistic model has made the CJC-1295/ipamorelin combination a standard reference tool in GH axis research. The CJC-1295/Ipamorelin blend available from Maple Research Labs is manufactured to research-grade purity standards with batch-specific third-party COA verification.
CJC-1295 Variants: Choosing the Right Research Tool
Researchers working with CJC-1295 must select between two pharmacologically distinct variants, each suited to different experimental designs. The CJC-1295 (No DAC) variant, also called modified GRF(1-29) or Mod GRF, has a half-life of approximately 30 minutes and produces discrete GH pulses that decay within 2 to 3 hours. This variant is appropriate for research models examining acute GH pulse dynamics, circadian GH secretion patterns, and short-duration pharmacological challenges.
The CJC-1295 DAC variant produces sustained GH elevation over 6 to 14 days following a single injection. This profile is suited for research models examining chronic GH/IGF-1 axis activation, body composition effects under prolonged somatotropic stimulation, and comparative pharmacodynamics against other long-acting GH secretagogues like tesamorelin.
For a broader comparison of growth hormone secretagogues across different receptor pharmacologies, our growth hormone secretagogues comparison guide covers ipamorelin, CJC-1295, tesamorelin, and GHRP-6 in a unified research framework.
Stability, Storage, and Research Handling Considerations
CJC-1295 in lyophilized form demonstrates acceptable stability when stored at -20°C in a desiccated environment, with most manufacturers reporting shelf lives of 24 to 36 months under these conditions. Reconstituted CJC-1295 in bacteriostatic water should be refrigerated at 2 to 8°C and used within 4 to 6 weeks for optimal peptide integrity. The methionine-to-leucine substitution at position 27 reduces oxidative degradation susceptibility compared to native GHRH, but standard peptide handling protocols still apply. Researchers should avoid repeated freeze-thaw cycles and protect reconstituted solutions from light exposure.
For detailed guidance on peptide reconstitution procedures, solvent selection, and concentration calculations, see our peptide reconstitution research guide and the reconstitution calculator.
Regulatory and Research Context
CJC-1295 is not approved by Health Canada or the FDA for therapeutic use in humans. It is classified as a research compound and is available for in vitro research, preclinical investigation, and educational purposes. Researchers working with CJC-1295 should be aware that its regulatory status was reviewed in the 2024 FDA nomination process for bulk compounding substances, where it was ultimately withdrawn from Category 2 consideration. Standard 503A and 503B pharmacy regulations apply to any compounding applications.
All CJC-1295 products from Maple Research Labs are supplied exclusively for research purposes with batch-specific certificates of analysis from independent third-party testing laboratories. For research purposes only. Not for human consumption. Not for diagnostic or therapeutic use.