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Molecular Weight
Purity
Storage
Appearance
Solubility
01
CJC-1295 (No DAC), also known as Modified GRF(1–29) or tetrasubstituted GRF(1–29), is a synthetic analogue of the first 29 residues of growth hormone-releasing hormone (GHRH). This N-terminal fragment is the shortest portion of GHRH that retains full receptor activity, and it is the same backbone used in sermorelin.
Four amino acids in that sequence are replaced to make the peptide far more resistant to enzymatic breakdown, and the C-terminus is amidated. Unlike CJC-1295 with DAC, it carries no albumin-binding group, so it behaves as a short, unconjugated peptide. It is supplied as a lyophilized reference material for in vitro GHRH receptor studies, protease-stability work and structure–activity comparisons between GHRH analogues.
02
Each of the four substitutions targets a known weak point in native GHRH(1–29):
Position 2: Ala → D-Ala
Dipeptidyl peptidase-IV (DPP-IV) removes the first two residues of native GHRH by cutting after Ala2. Swapping in the D-form of alanine prevents the enzyme from recognising this site, which is the main route of rapid inactivation.
Position 8: Asn → Gln
Native Asn8 sits next to Ser9, a sequence prone to deamidation and rearrangement. Glutamine is far slower to deamidate, which improves chemical stability.
Position 15: Gly → Ala
Alanine favours helix formation more strongly than glycine, helping to stabilise the central helical region involved in receptor binding.
Position 27: Met → Leu
Methionine oxidises readily. Leucine has a similar size but no sulfur, removing the main oxidation risk.
The C-terminal amide (–NH₂) mirrors the native hormone and protects the C-terminus from carboxypeptidases. The result is a 29-residue peptide with an unchanged binding framework but much better enzymatic and chemical stability than the unmodified fragment.
03
In vitro, CJC-1295 (No DAC) is studied as an agonist of the GHRH receptor, a G protein-coupled receptor found on pituitary somatotroph cells.
Receptor binding
Competition binding assays with membranes from GHRH receptor-expressing cells compare its affinity with native GHRH(1–29) and other analogues.
Signalling
Cell-based assays measure cAMP production after receptor activation to characterise potency and efficacy.
Protease resistance
Incubation with purified DPP-IV and other proteases, followed by HPLC or MS, measures how much each substitution slows degradation compared with the unmodified sequence.
All observations described here come from cell-free and cell-based in vitro systems.
04
GHRH receptor comparator
Used alongside native GHRH(1–29), sermorelin and CJC-1295 with DAC in binding and signalling assays.
Stability benchmark
Its defined substitution pattern makes it a useful reference when testing the protease resistance of other modified peptides under standard conditions.
Mass spectrometry reference
At about 3.4 kDa it forms several multiply charged ions in ESI-MS (commonly +3 to +5), which is helpful when setting up methods for mid-sized peptides.
Stability-indicating methods
Comparing its degradation with native GHRH(1–29) under stress conditions helps develop and validate stability-indicating HPLC methods.
05
Storage
Store the lyophilized powder at −20 °C, sealed and desiccated. Let the vial reach room temperature before opening to avoid condensation.
Reconstitution
Dissolves readily in water or neutral aqueous buffer thanks to its many charged residues. Swirl gently rather than vortexing to limit foaming and aggregation.
Solutions
Prepare fresh where possible. For storage, divide into single-use aliquots and freeze to avoid repeated freeze–thaw cycles.
Remaining weak points
With Met27 removed, oxidation is much less of a concern. Aspartate-containing bonds can still hydrolyse slowly under acidic conditions, and the glutamine residues may deamidate during prolonged storage in solution.
Labware
Use low-binding polypropylene tubes and tips to reduce peptide loss to surfaces at low concentrations.
06
Characterisation needs to confirm the sequence, the four substitutions, the D-configuration at position 2 and the C-terminal amide.
HPLC
Reversed-phase C18 with a wide-pore (300 Å) column and a shallow acetonitrile gradient gives good resolution from truncated and modified impurities.
Mass spectrometry
ESI-MS should match the expected mass of 3367.9 Da across its charge states. Because the peptide contains no methionine, a +16 Da oxidation peak should not appear. MS/MS confirms the sequence and substitution positions.
D-Ala2 verification
Mass spectrometry cannot tell D- from L-alanine. The configuration is confirmed by chiral amino acid analysis after hydrolysis, or by comparison with an L-Ala2 reference on a chiral or high-resolution method.
Amidation
The free-acid form differs by only about 1 Da, so it is checked by high-resolution MS or by HPLC against a reference standard.
Impurity profile
Typical impurities to check for include truncated or deletion sequences, the free-acid form and residual synthesis reagents.
07
Both share the same modified 29-residue GHRH sequence. The DAC version adds a lysine carrying a maleimide group that binds serum albumin, which makes it larger (about 3647 g/mol vs 3367.9 g/mol) and changes its stability profile. The No DAC version has no albumin-binding group.
Four: Ala2 to D-Ala, Asn8 to Gln, Gly15 to Ala and Met27 to Leu. The C-terminus is amidated, as in the native hormone.
Mass spectrometry cannot distinguish D from L forms, so the configuration is confirmed by chiral amino acid analysis after hydrolysis or by chromatographic comparison with an L-Ala2 reference.
The free-acid form differs by about 1 Da, so it is measured by high-resolution mass spectrometry or by HPLC against a reference standard and reported as a specified impurity on the certificate of analysis.
No. It is supplied strictly as a reference compound for laboratory and analytical research and is not for human or animal use.
CJC-1295 (No DAC) Research Reference. (2026). Pure Peptides Labs Research Catalogue. Retrieved from https://purepeptideslabs.net/research-catalogue/growth-hormone-axis-research-peptides/cjc-1295-no-dac/
Materials listed on this platform are supported by independent testing and published documentation for laboratory research contexts.
