Table of Contents
Structure and the DAC Modification
The base sequence of CJC-1295 corresponds to GHRH(1-29)-NH2 — the first 29 amino acids of growth hormone-releasing hormone, amidated at the C-terminus. This fragment retains full GHRH receptor binding activity; the biologically active region of GHRH is contained within its first 29 residues, and C-terminal truncation does not substantially diminish receptor engagement.
The DAC (Drug Affinity Complex) modification is introduced at position Lys(33) — but in CJC-1295's 30-residue form, it is a modification at the C-terminal end via a maleimido-containing linker that reacts with the free thiol group of circulating albumin's cysteine-34 residue. This reaction is a thiol-maleimide conjugation — a selective, covalent bond that forms under physiological conditions in the bloodstream.
The result is that CJC-1295, once in circulation, binds covalently to albumin. Because albumin has a half-life of approximately 19 days and is not rapidly cleared by the kidney (it exceeds the glomerular filtration size threshold), the albumin-bound CJC-1295 remains in circulation far longer than any unmodified GHRH analogue. This is the structural basis for CJC-1295's extended half-life.
Extended Half-Life Mechanism
The distinction between CJC-1295 (with DAC) and GHRH(1-29)-NH2 without the DAC modification is clinically and pharmacologically significant. GHRH(1-29)-NH2 without modification — sometimes sold under other names in the research market — has a half-life measured in minutes due to rapid DPP-IV cleavage. CJC-1295's DAC modification converts this short-acting fragment into a compound with a half-life measured in days.
Published pharmacokinetic studies report CJC-1295's mean half-life as approximately 6–8 days following a single administration in controlled clinical research settings. This extended half-life changes the nature of GH pulsatility that can be studied in research models — rather than producing a single acute GH pulse following each administration, CJC-1295 produces a sustained elevation of the GHRH receptor stimulation baseline, against which endogenous pulsatile GH secretion continues.
This pharmacokinetic profile makes CJC-1295 particularly relevant for research questions involving sustained GHRH receptor engagement, GH axis down-regulation, or long-term in vivo model studies. For acute receptor stimulation studies, shorter-acting GHRH analogues like Sermorelin may be more appropriate depending on study design.
Published Research Summary
CJC-1295 has been studied in multiple clinical investigations, with published data including pharmacokinetic characterization, GH and IGF-1 response profiles, and safety observations under controlled clinical trial conditions. A foundational Phase 1/2 clinical trial published in the Journal of Clinical Endocrinology and Metabolism characterized the compound's dose-response relationship, half-life, and GH/IGF-1 modulation across multiple dose levels and dosing intervals in healthy adult volunteers.
Beyond the primary clinical pharmacokinetic literature, CJC-1295 is represented in preclinical research examining GHRH receptor biology, pituitary somatotroph function, and GH secretory pulse pattern modulation in rodent models. The compound's extended half-life makes it a useful tool for creating stable GHRH receptor stimulation conditions in chronic in vivo study designs where repeated acute administrations would be impractical.
Researchers building literature reviews should search PubMed using "CJC-1295," "DAC-GRF," "GHRH analogue half-life," and related terms. The primary Sackler et al. (2006) publication in JCEM is the foundational clinical pharmacokinetics reference for this compound.
CJC-1295 vs. Sermorelin and Tesamorelin
Within the GHRH-axis research compound landscape, CJC-1295, Sermorelin, and Tesamorelin represent three distinct pharmacological tools with overlapping but non-identical applications:
- Sermorelin — GHRH(1-29)-NH2 without modification. Shortest half-life among the three; appropriate for acute receptor stimulation studies where time-course resolution is important. Widest preclinical literature base due to its long availability as a research tool.
- Tesamorelin — GHRH(1-44)-NH2 with N-terminal trans-3-hexenoic acid. Intermediate modification; provides DPP-IV protection at the N-terminus without albumin binding. Half-life intermediate between Sermorelin and CJC-1295. Selected for studies where the full GHRH sequence length is relevant to the research question.
- CJC-1295 — GHRH(1-29)-NH2 with DAC (albumin-binding modification). Longest half-life among the three — days rather than hours. Selected for studies requiring sustained, long-duration GHRH receptor engagement or chronic in vivo study designs with infrequent administration intervals.
All three are available in the performance research category. The article on Tesamorelin provides a parallel research overview for that compound.
Quality Documentation for CJC-1295
CJC-1295's DAC modification — the maleimido-linker and fatty acid chain — must be confirmed by mass spectrometry in addition to HPLC purity assessment. The DAC modification adds a specific mass increment to the peptide backbone; MS data showing the observed molecular weight matching the expected value for the fully modified compound is the only way to confirm that the modification is present and intact.
A vial supplied as "CJC-1295" but containing only the unmodified GHRH(1-29)-NH2 base sequence would be substantially different in pharmacological terms from the DAC-modified compound — but the two might appear similar on HPLC unless the column and gradient conditions are specifically optimized for their separation. This makes MS confirmation non-negotiable for CJC-1295.
Expected COA data for research-grade CJC-1295 includes: HPLC purity ≥98%, MS confirmation of observed molecular weight consistent with DAC-modified CJC-1295 (~3647 Da), lot number, testing date, and third-party laboratory identification. See the COA reading guide for comprehensive interpretation guidance and the lab testing page for Peptides Canada's testing methodology.
Sourcing CJC-1295 for Canadian Research
CJC-1295 is available from Peptides Canada as CJC-1295 10mg, supplied for research and laboratory use with HPLC-verified purity. The compound ships domestically within Canada. Given the importance of MS confirmation for this modified peptide, researchers are encouraged to request complete COA documentation — including MS data — before use in any research protocol.
For questions about documentation, compound selection within the GHRH-axis research category, or protocol considerations, use the contact form. Common questions about reconstitution, storage, and sourcing are also addressed in the FAQ. To browse the full performance research category including CJC-1295, Sermorelin, Tesamorelin, and Ipamorelin, visit the performance collection.