CJC-1295 vs Sermorelin: Two GHRH Analogs Compared

CJC-1295 and sermorelin are both analogs of growth hormone-releasing hormone, or GHRH. They share a starting sequence and a receptor, yet they behave differently in model systems. This comparison of CJC-1295 vs sermorelin covers how their sequences relate, how long each persists, what the DAC and No DAC forms mean, and how the choice shapes study design. All are research-use-only materials.

What is the difference between CJC-1295 and sermorelin?

Sermorelin is the unmodified first 29 amino acids of human GHRH, while CJC-1295 is a modified version of that same fragment built to resist enzymatic breakdown.

Native GHRH is 44 residues long. The first 29, written GHRH(1-29), form the fragment reported to keep the full intrinsic activity of the native hormone. Sermorelin is that fragment. Its synonyms include GRF(1-29).

CJC-1295 starts from the same 1-29 fragment and adds amino acid substitutions. The No DAC form is that substituted analog alone. The DAC form adds an albumin-binding group on top of those substitutions.

• Sermorelin: GHRH(1-29), CAS 86168-78-7, formula C149H246N44O42S, about 3357.93 g/mol.
• CJC-1295 No DAC: modified GRF (1-29), CAS 863288-34-0, formula C152H252N44O42, about 3367.9 g/mol.
• CJC-1295 With DAC: modified GRF (1-29) plus DAC, CAS 446262-90-4, formula C165H269N47O46, about 3647.2 g/mol.

How do the sermorelin and CJC-1295 sequences relate?

All three share the GHRH(1-29) backbone. The differences are substitutions and, in one form, an added group.

Sermorelin keeps the native N-terminal sequence responsible for receptor binding and activation. It omits the C-terminal residues that are not needed for full activity. That makes it a reference point in structure-activity work within the GHRH family.

CJC-1295 No DAC is also called tetrasubstituted GRF (1-29) and Mod GRF 1-29. The names reflect amino acid swaps relative to the native sequence. The four swaps are D-Ala2, Gln8, Ala15, and Leu27. D-Ala2 is studied for resisting cleavage by dipeptidyl-peptidase-4, an enzyme that cuts native GHRH. The other three are studied for improving stability and potency, while GHRH receptor engagement is kept.

Placing sermorelin and CJC-1295 No DAC side by side therefore isolates the effect of the substitutions. The receptor and the core sequence stay the same.

Do CJC-1295 and sermorelin act on the same receptor?

Yes. Both are GHRH receptor agonists acting on somatotroph cells in the anterior pituitary.

The GHRH receptor, GHRHR, is a G-protein-coupled receptor. In model systems, its activation is associated with cAMP-mediated signaling that drives the synthesis and pulsed release of growth hormone. Because these peptides act upstream at the pituitary, they are used to study feedback regulation and the natural rhythm of the growth hormone axis. The sermorelin mechanism of action article covers that signaling chain.

The shared target is the point of the comparison. Differences seen between them come from stability and persistence, not from a change in receptor.

How do stability and persistence differ?

Sermorelin carries the native sequence, CJC-1295 No DAC adds substitutions studied for resisting enzymatic cleavage, and CJC-1295 With DAC persists far longer than either.

The No DAC substitutions are studied for extending in vitro stability relative to the native peptide. Even so, the No DAC form is described as short-acting, because it has no albumin-binding group.

The DAC form adds a maleimidopropionyl group. This group reacts with a cysteine thiol on serum albumin to form a covalent bond. In experimental systems, that albumin link is associated with markedly prolonged persistence and sustained receptor engagement.

What do the DAC and No DAC forms mean for this comparison?

DAC is an albumin-binding group added to CJC-1295, and its presence decides whether the analog is studied as short-acting or long-acting.

That gives a three-step series on one backbone. Sermorelin is native GHRH(1-29). CJC-1295 No DAC adds stabilizing substitutions. CJC-1295 With DAC adds albumin binding on top. Each step changes one property, which suits stepwise comparison designs.

The No DAC form fits studies of timed, pulsed receptor signaling. The DAC form fits studies of sustained receptor occupancy and IGF-related responses over time. The CJC-1295 DAC vs No DAC comparison goes deeper on that split.

Sermorelin or CJC-1295: which fits which study design?

The choice follows from which property the question isolates.

• Reference GHRH(1-29) activity, structure-activity work, or feedback studies: sermorelin, supplied as a 10 mg vial.
• Effect of stabilizing substitutions, or pulsed, time-resolved signaling: CJC-1295 No DAC, supplied as a 10 mg vial.
• Sustained GHRH receptor occupancy or albumin-binding persistence: CJC-1295 With DAC, supplied as a 5 mg vial.
• Convergent signaling with a ghrelin receptor agonist: CJC-1295 No DAC is the form usually paired with ipamorelin, as the ipamorelin vs CJC-1295 comparison explains.

Because all three act on the same receptor, matched assay conditions matter. Keep the same cell model, the same readout, and the same timing window across arms. Then differences can be credited to the molecule rather than to the setup.

How are these GHRH analogs handled in the lab?

All three ship as a solid white lyophilized powder in a sealed glass vial, with the same storage guidance.

• Store sealed at or below 25 degrees Celsius, away from heat, light, and moisture.
• For extended storage, keep the material lyophilized and refrigerated or frozen.
• Keep reconstituted peptide refrigerated and use it within the window your lab's SOP sets.
• Record lot numbers and storage conditions for every arm of the study.

Sermorelin and CJC-1295 No DAC differ in molecular weight by only about 10 g/mol, and the powders look the same. Mass spectrometry on the certificate of analysis is the reliable way to confirm identity. Every batch ships with third-party HPLC purity and mass-spectrometry identity data. Puritide Research sources and independently tests these materials. It does not make them in-house.

For research use only. Sermorelin and CJC-1295 are laboratory research compounds supplied for in vitro and preclinical investigation. Neither is supplied for human or veterinary use, and nothing above is medical guidance or a description of outcomes in people.