CJC-1295

What is CJC-1295?

CJC-1295 (no DAC), also sold as modified GRF (1-29) or Mod GRF 1-29, is a synthetic 29-residue analogue of the biologically active N-terminal fragment of human growth hormone releasing hormone, molecular formula C₁₅₂H₂₅₂N₄₄O₄₂, molecular weight 3367.9 g/mol. It carries four substitutions on the hGRF(1-29) backbone, D-Ala2, Gln8, Ala15 and Leu27, chosen to resist dipeptidyl peptidase-4 cleavage at the N-terminus and to reduce asparagine rearrangement and methionine oxidation elsewhere in the sequence, extending a native half-life of minutes to roughly thirty minutes without any conjugation chemistry. It is an agonist at the GHRH receptor on anterior pituitary somatotrophs, stimulating growth hormone synthesis and release, and because its action is short it preserves the pulsatile character of GH secretion in experimental systems. The name CJC-1295 originally described the DAC-conjugated molecule characterised by ConjuChem; the research market applies it loosely to both forms, so the mass on the certificate of analysis, 3367.9 against 3647.2 g/mol, is the definitive identity check. Supplied as lyophilised powder for in-vitro research use only.

CJC-1295 No-DAC vs CJC-1295 DAC

The two forms share the same tetrasubstituted GRF(1-29) backbone, the same receptor and the same binding mode; everything that separates them is at the C-terminus. The no-DAC form stops at residue 29 and is cleared within the order of thirty minutes. The DAC form adds a thirtieth lysine carrying 3-maleimidopropionic acid, a Michael acceptor that reacts covalently with Cys34 of serum albumin, and Teichman and colleagues (J Clin Endocrinol Metab, 2006) reported the resulting terminal half-life at roughly 6 to 8 days. The 279.3 g/mol mass difference is the simplest bench check on which form a vial actually contains. Experimentally the choice is about exposure profile: the no-DAC form gives a short, controllable stimulus that mimics a physiological GHRH pulse and washes out quickly, making it the tool for pulsatility and kinetics work, while the DAC form gives sustained receptor occupancy for questions about continuous stimulation. The often-repeated claim that continuous stimulation abolishes GH pulsatility is not supported by the published data, which reported pulsatile secretion persisting during continuous CJC-1295 exposure. Neither form is an approved medicine.

CJC-1295 Research Applications

CJC-1295 (no DAC) is studied in endocrine research on GHRH receptor pharmacology, somatotroph cell biology, pulsatile growth hormone release kinetics and downstream IGF-1 production. Its short duration makes it the appropriate GHRH-receptor tool where the experimental design needs a discrete, pulse-like stimulus rather than sustained occupancy, and it is the standard GHRH-side partner in two-receptor studies pairing a GRF analogue with a ghrelin-receptor agonist such as ipamorelin to examine convergence of the two pathways on somatotroph GH release. It also appears in anti-doping analytical method development, since GRF analogues are prohibited in sport and detection assays for modified GRF (1-29) and its metabolites in plasma and urine are an established literature. Human pharmacology data exist for the DAC-conjugated molecule; findings from that literature should not be transferred uncritically to the no-DAC form, whose exposure profile is fundamentally different.

Reconstitution Guide

Allow vials to reach room temperature, then sterilise the rubber stopper of both the peptide vial and the bacteriostatic water vial with an alcohol swab. Slowly draw your bacteriostatic water into a sterile insulin syringe, then inject it gently down the inner glass wall of the peptide vial, never directly onto the lyophilised powder. Once added, gently swirl the vial in a slow circular motion until fully dissolved. Never shake or vortex, a 29-residue GRF analogue is long enough for shear and interface agitation to reduce recovery of intact peptide. The solution should be clear and colourless. Label the vial with the reconstitution date and refrigerate immediately.

See our full peptide reconstitution guide and reconstitution calculator for step-by-step protocol.

Storage Instructions

Lyophilised vials should be stored at -20°C, protected from light and moisture, and remain stable for up to 24 months. Once reconstituted with bacteriostatic water, store the solution at 2-8°C and use within approximately 4 weeks, preparing single-use aliquots at -20°C for longer storage. Although the Leu27 substitution removes the methionine oxidation liability of the native sequence, GRF analogues remain degradation-prone in dilute standing solution, and repeated freeze-thaw cycling is the main avoidable failure mode, so aliquot at reconstitution rather than repeatedly accessing one stock. Handle under sterile laboratory conditions throughout.

Frequently Asked Questions

Research References

• Sustained-release GHRH analog CJC-1295 stimulates GH and IGF-I (J Clin Endocrinol Metab, 2006)
• Pulsatile GH secretion and GHRH analogues, review (Endocr Rev, 2003)

Related Research Compounds

• → Ipamorelin 5mg
• → CJC-1295 + Ipamorelin 5+5mg
• → Sermorelin 5mg
• → Bacteriostatic Water 10ml