CJC-1295 DAC vs No DAC: A Research Comparison

CJC-1295 comes to the lab in two forms. They share the same peptide backbone and differ by one added chemical group. That group is the Drug Affinity Complex, or DAC. It does not change which receptor the molecule acts on. It only changes how long the molecule stays available to act. This comparison sets the two side by side, so a study design can be matched to the exposure profile it needs.

What do CJC-1295 DAC and No DAC share?

Both forms are built on the same GHRH (1-29) backbone and act on the same receptor. Both are synthetic analogs of growth hormone-releasing hormone, or GHRH. GHRH (1-29) is the first 29 amino acids of the native hormone. It is the active fragment.

Both carry stabilizing amino acid swaps compared with the native sequence. These swaps are studied for making the peptide harder for dipeptidyl-peptidase to cut. They are also studied for better stability in vitro.

Both are studied at the same target: the GHRH receptor on pituitary somatotroph cells. In test systems, action at this receptor is linked to cAMP-driven signaling.

The receptor target is the same. So choosing between the two is not a question of receptor pharmacology. It is a question of exposure over time.

Every later difference in study design follows from how long the peptide stays present. This includes sampling times and the expected shape of the signaling curve. For receptor detail on each, see the CJC-1295 With DAC mechanism of action and the CJC-1295 No DAC mechanism of action write-ups.

What is the Drug Affinity Complex?

The DAC is a chemical group that lets the peptide latch onto albumin, a long-lived blood protein. Chemically, it is a maleimidopropionyl group added to the peptide.

Maleimide chemistry targets thiols. The maleimide ring reacts with a free cysteine thiol. In a system that contains serum, the most common available partner is serum albumin. The reaction forms a covalent bond. The result is a peptide-albumin conjugate, not a free peptide.

Albumin is a carrier protein that clears slowly. Linking the analog to it turns a small, fast-clearing peptide into a much larger complex. That complex lasts far longer in solution.

In test systems, this albumin link is tied to much longer persistence and steady receptor activity. That is why CJC-1295 With DAC is seen as a long-acting GHRH receptor tool, not just a stronger version.

The No-DAC form is widely called modified GRF (1-29) or Mod GRF 1-29. It leaves out the maleimide group entirely. With no albumin link, CJC-1295 No DAC clears much faster. It keeps the stabilizing swaps but none of the half-life extension. It is studied as a short-acting GHRH receptor agonist.

How does the half-life difference play out in practice?

The practical result is a large gap in how long exposure lasts. The No-DAC form gives a brief, well-bounded stimulus. The DAC form gives an extended one.

In research models, that is the difference between two questions. What does a somatotroph do when stimulated once? And what does it do when stimulation does not stop?

That gap is a deliberate research feature, not a flaw in either form. Some labs need a molecule that stays present. They study receptor desensitization, later IGF-related responses, or half-life extension itself. Other labs study the onset, peak, and decline of a single signaling event. They need a molecule that clears.

Running both in one framework isolates duration as a variable. Receptor identity stays the same.

How do pulsed and sustained GHRH receptor signaling differ?

Native GHRH signaling in the growth hormone axis comes in bursts. The No-DAC form is the closer match to that pattern in a model system.

Its short life supports timed work:

• Single, discrete stimulation.
• A defined washout period.
• Repeat-challenge protocols, where each event can be traced to a known input, not to built-up exposure.

The DAC form models the opposite condition: a receptor that is always available to act. Published work on long-acting GHRH analogs reports that pulsed growth hormone release continues during constant stimulation. So the sustained condition is not just a flattened version of the pulsed one.

Labs use the DAC form to study how a constant GHRH receptor input interacts with the body's own rhythm-generating systems in animal models.

How do the specifications compare side by side?

The two forms are distinct chemicals with their own identifiers. So lot records should be checked against the correct set.

• CJC-1295 With DAC: molecular formula C165H269N47O46, molecular weight about 3647.2 g/mol, CAS 446262-90-4. Synonyms include CJC-1295 DAC, DAC:GRF, and GRF (1-29) drug affinity complex.
• CJC-1295 No DAC: molecular formula C152H252N44O42, molecular weight about 3367.9 g/mol, CAS 863288-34-0. Synonyms include modified GRF (1-29), Mod GRF 1-29, and tetrasubstituted GRF (1-29).
• Shared format: both come as a solid white freeze-dried powder in a sealed glass vial. Puritide Research supplies the DAC form in a 5 mg vial and the No-DAC form in a 10 mg vial. Each has a stated purity of at least 99 percent.

The mass difference between the two is the DAC linker itself. That makes it a useful check point when reviewing mass spectrometry identity data on a new lot.

Which form fits which research question?

Neither form is better in the abstract. The choice follows from what the protocol needs to answer.

• Timed or pulsed signaling models: the No-DAC form. A short stimulus and a clean decline are the point of the experiment.
• Steady receptor occupancy and duration-driven signaling: the DAC form. This includes work on how persistence shapes receptor behavior over days, not minutes.
• Convergent pathway studies: the No-DAC form is often paired with a GHS receptor agonist such as Ipamorelin. Two distinct receptor inputs can then be timed against each other. The CJC No DAC and Ipamorelin research blend supplies both compounds for this kind of model.
• Half-life engineering as the subject: both forms together, with the DAC strategy as the test variable.

How are both forms handled, stored, and verified?

Handling is essentially the same for both forms:

• Store freeze-dried material at or below 25 degrees Celsius, sealed and away from heat, light, and moisture.
• Keep it chilled or frozen for long storage.
• Keep dissolved peptide in the fridge and use it within the window the protocol sets.
• Split it into aliquots to avoid repeated freeze-thaw cycles.

Qualified staff handle both under institutional standard procedures and chemical hygiene plans, with suitable protective gear. Record lot numbers, storage conditions, and handling events, so results stay traceable.

Puritide Research sources and supplies both forms with a third-party-verified Certificate of Analysis for each batch. It covers HPLC purity, identity by mass spectrometry, and lot, date, and method details.

Common research questions

Is DAC or No DAC better for laboratory research?

Neither is better in every case, because they answer different questions. The No-DAC form suits short, timed, pulsed signaling models. The DAC form suits models with sustained exposure. The research question decides the choice, not a ranking.

What does Mod GRF 1-29 refer to?

Mod GRF 1-29, or modified GRF (1-29), is the common name for the No-DAC form. It is the GHRH (1-29) analog with four stabilizing swaps and no albumin-binding group.

Do the two forms bind different receptors?

No. Both are studied at the GHRH receptor on pituitary somatotroph cells. The DAC changes how long the peptide stays in the system, not which receptor it binds. That sets both apart from GHS receptor agonists such as Ipamorelin, which act on a separate pathway.

For research use only. Both forms are laboratory research compounds supplied strictly for in vitro and preclinical investigation. Neither is approved for human or veterinary use, and nothing above is medical, therapeutic, or dosing guidance.