CJC-1295: Growth Hormone Releasing Hormone Analog Research

Compiled by the APL Research TeamSourced directly from peer-reviewed pharmacological literature and clinical guidelines.

Key Takeaways

• Expert Insight: An overview of CJC-1295, a synthetic GHRH analog, covering its mechanism of action, DAC modification, pharmacokinetics, and key findings in growth hormone research.
• Quality Assurance: All discussed methodologies align with stringent Australian laboratory standards.
• Clinical Relevance: Critical informational resource for verifying the stability and purity of cjc-1295: growth hormone releasing hormone analog research in-vitro.

Introduction

CJC-1295 is a synthetic analog of growth hormone releasing hormone (GHRH, also known as somatoliberin), the 44-amino acid hypothalamic peptide that stimulates growth hormone (GH) secretion from the anterior pituitary. CJC-1295 was developed to address the primary limitation of native GHRH as a research tool — its extremely short plasma half-life of approximately 7 minutes due to rapid enzymatic degradation by dipeptidyl peptidase IV (DPP-IV).

The peptide exists in two primary forms in the research literature: CJC-1295 without DAC (also referred to as Modified GRF 1-29) and CJC-1295 with DAC (Drug Affinity Complex), each with distinct pharmacokinetic profiles.

Molecular Profile

GHRH Signalling Pathway

To understand CJC-1295, it is necessary to understand the GH axis:

1. Hypothalamus releases GHRH in a pulsatile fashion
2. GHRH binds to GHRH receptors (GHRH-R) on somatotroph cells in the anterior pituitary
3. GHRH-R activation triggers a G-protein coupled cascade → adenylyl cyclase → cAMP → protein kinase A
4. GH synthesis and secretion — both immediate release from stored granules and longer-term transcriptional upregulation of the GH gene
5. GH acts on target tissues directly and via stimulation of hepatic IGF-1 production
6. Negative feedback — GH and IGF-1 feed back to the hypothalamus, increasing somatostatin release and decreasing GHRH, completing the regulatory loop

CJC-1295 acts at step 2, binding the GHRH receptor with similar affinity to native GHRH but with significantly extended duration of action.

Modifications and DPP-IV Resistance

Native GHRH(1-29) is rapidly inactivated by DPP-IV, which cleaves the Tyr¹-Ala² bond at the N-terminus. CJC-1295 incorporates four amino acid substitutions that confer DPP-IV resistance:

• Position 2: Ala → D-Ala (D-amino acid substitution prevents DPP-IV recognition)
• Position 8: Asn → Gln (reduces deamidation)
• Position 15: Gly → Ala (improves metabolic stability)
• Position 27: Met → Leu (prevents oxidation)

These modifications extend the half-life from ~7 minutes (native GHRH) to ~30 minutes (CJC-1295 without DAC).

The DAC Modification

The Drug Affinity Complex (DAC) is a lysine-maleimidopropionic acid linker that enables covalent, irreversible binding to serum albumin after injection. This albumin conjugation:

• Dramatically extends the half-life to approximately 8 days
• Reduces renal clearance (albumin-bound peptides are not filtered by the kidneys)
• Creates a sustained, non-pulsatile elevation of GH levels
• Changes the pharmacokinetic profile from acute to chronic exposure

This distinction is significant for research design, as pulsatile versus continuous GH release produces different downstream effects in animal models.

Key Research Findings

Pharmacokinetic Studies

The foundational pharmacokinetic research on CJC-1295 was conducted by ConjuChem Biotechnologies:

• Single-dose administration of CJC-1295 DAC in healthy adults produced dose-dependent increases in mean GH levels sustained for 6-14 days
• IGF-1 levels increased 1.5-3x above baseline, peaking at 8-11 days post-dose
• No significant tachyphylaxis (tolerance) was observed over the study period
• The GH response was maintained over multiple dosing cycles in extended studies

GH Pulsatility Research

Comparative studies between the DAC and non-DAC forms have provided insights into GH release dynamics:

• CJC-1295 without DAC preserves the natural pulsatile pattern of GH release, amplifying endogenous pulses
• CJC-1295 with DAC elevates the baseline GH level, blunting the pulsatile pattern
• The distinction is relevant because GH pulse frequency and amplitude have differential effects on hepatic gene expression, lipolysis, and tissue growth in animal models

Synergy with GH Secretagogues

Research has examined the co-administration of CJC-1295 (GHRH analog) with GH secretagogues (GHS, which act via the ghrelin receptor):

• GHRH and GHS act on different receptor systems and produce synergistic (greater than additive) GH release
• This synergy reflects the complementary mechanisms: GHRH increases GH synthesis and release, while GHS amplifies the pulse amplitude and suppresses somatostatin
• Combined administration in animal models produces GH responses 2-3x greater than either agent alone

Body Composition Studies

Animal studies have examined the effects of sustained GH elevation via CJC-1295 DAC:

• Increased lean body mass in GH-deficient rodent models
• Reduced adipose tissue mass, particularly visceral fat depots
• Increased bone mineral density in aged animal models
• Enhanced nitrogen retention, indicating increased protein synthesis

GHRH Receptor Pharmacology

The GHRH receptor is a class B G-protein coupled receptor (GPCR) with distinct pharmacological properties:

• Expressed primarily on anterior pituitary somatotrophs
• Also expressed in extrapituitary tissues (immune cells, gastrointestinal tract, kidneys) — relevance of these sites is under active investigation
• Receptor desensitisation occurs with continuous GHRH exposure (relevant to the DAC vs. non-DAC distinction)
• Receptor expression is regulated by glucocorticoids, thyroid hormones, and sex steroids

Research Considerations

CJC-1295 is supplied as a lyophilised white powder. Both DAC and non-DAC forms should be reconstituted with bacteriostatic water for multi-use applications. See our Reconstitution Best Practices guide for detailed protocols.

Storage: -20°C for lyophilised material; 2-8°C after reconstitution. The DAC form is particularly sensitive to pH and should be reconstituted at neutral pH to prevent premature maleimide hydrolysis.

Because the DAC and non-DAC forms are not interchangeable, laboratories sourcing locally should confirm which form a batch contains — our CJC-1295 Australia research guide covers domestic supply, purity verification and COA expectations.

All research involving CJC-1295 should be conducted in accordance with institutional guidelines. This compound is designated for laboratory research use only.

The DAC and non-DAC forms are different molecules and are assayed separately: CJC-1295 (No DAC) batch certificates and CJC-1295 (DAC) batch certificates each publish their own chromatogram, ion channels and result table.

Frequently Asked Questions

Is CJC-1295 legal to buy and research in Australia? CJC-1295 is supplied strictly as a research chemical for in-vitro laboratory use. It is not approved for human therapeutic use in Australia and is not for human or animal consumption. Researchers are responsible for compliance with Therapeutic Goods Administration (TGA) regulations and their institution's protocols.

What is the difference between CJC-1295 with and without DAC? CJC-1295 without DAC (also called Modified GRF 1-29) has a half-life of roughly 30 minutes and amplifies the natural pulsatile pattern of GH release in research models. CJC-1295 with DAC adds a Drug Affinity Complex linker that binds serum albumin, extending the half-life to approximately 8 days and producing a sustained, non-pulsatile elevation. The distinction is significant for research design.

What is CJC-1295 studied for in research? CJC-1295 is a synthetic GHRH analog studied in preclinical work for GHRH-receptor agonism and downstream growth-hormone and IGF-1 dynamics, GH pulsatility, synergy with growth-hormone secretagogues, and body-composition endpoints in animal models. These are laboratory findings only and do not establish any effect in humans.

How is the purity of CJC-1295 verified? Every batch is analysed in-house by HPLC and mass spectrometry and ships with a Certificate of Analysis. Select batches also undergo independent, third-party purity verification.

Does Australian Peptide Labs provide CJC-1295 dosing protocols? No. As these compounds are supplied for laboratory research only, we do not provide dosing or administration protocols. Our research library covers reconstitution and concentration calculations for in-vitro work.

References

1. Teichman, S.L. et al. "Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults." The Journal of Clinical Endocrinology and Metabolism, 2006. — PubMed: 16352683
2. Alba, M. et al. "Once-daily administration of CJC-1295, a long-acting growth hormone-releasing hormone (GHRH) analog, normalizes growth in the GHRH knockout mouse." American Journal of Physiology. Endocrinology and Metabolism, 2006. — PubMed: 16822960
3. Nass, R. et al. "Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial." Annals of Internal Medicine, 2008. — PubMed: 18981485

⚠️ Medical & Regulatory Disclaimer:
The information provided in this academic article is intended exclusively for educational and laboratory research purposes. It does NOT constitute medical advice. Compounds discussed are strictly for in-vitro research and development only, and are not intended for human consumption, veterinary use, or clinical treatment. Always adhere to Australian Therapeutic Goods Administration (TGA) regulations and your institution's ethical guidelines when handling research chemicals.