CJC-1295 is one of the more frequently confused compounds in research-peptide circulation because it exists in two forms — With-DAC and No-DAC — that share the same 30-amino-acid base sequence but differ dramatically in their physiological half-life. The two are often discussed as if they were interchangeable; they are not. This guide explains the difference, the research-context implications, and how to verify which form is in the vial.
At a glance
- Both forms share the same 30-amino-acid Modified GRF(1-29) sequence
- DAC = "Drug Affinity Complex" — a maleimidopropionyl group attached to a specific lysine residue
- The DAC modification enables covalent binding to serum albumin in physiological systems
- Albumin binding dramatically extends half-life — from hours (No-DAC) to days (With-DAC)
- Mass Spectrometry is the verification step that distinguishes the two forms
What's the same
Both With-DAC and No-DAC versions of CJC-1295 share the same 30-amino-acid base sequence: Modified GRF(1-29), a stabilized analogue of growth-hormone-releasing hormone (GHRH). The sequence carries four amino-acid substitutions from native GHRH(1-29) designed to resist enzymatic degradation. At the level of receptor binding, both forms act at the GHRH receptor.
What's different: the DAC modification
The DAC version of CJC-1295 carries a maleimidopropionyl group covalently attached to a specific lysine residue. The maleimide chemistry is reactive toward free thiols — specifically, the cysteine-34 residue of human serum albumin. In a physiological setting, the DAC-modified peptide forms a covalent bond with circulating albumin, effectively turning the entire peptide-albumin complex into a slow-release reservoir.
The No-DAC version lacks this modification. Without the albumin-binding moiety, the peptide circulates and clears on a much shorter timescale.
| CJC-1295 With-DAC | CJC-1295 No-DAC | |
|---|---|---|
| Base sequence | Modified GRF(1-29) | Modified GRF(1-29) |
| DAC modification | Yes (maleimidopropionyl) | No |
| Albumin binding | Covalent, via Cys34 of albumin | None |
| Approx. half-life in research models | Days | Hours |
| Typical research-protocol cadence | Less frequent dosing intervals | More frequent dosing intervals |
Research contexts where each is used
Research protocols studying acute GHRH-axis dynamics — pulsatile GH release, short-window receptor-binding kinetics, or co-administration timing with ghrelin-receptor agonists like Ipamorelin — typically use the No-DAC form, because its shorter half-life produces a discrete window of action that can be coordinated with other test compounds.
Protocols studying chronic GHRH-axis effects, sustained-exposure models, or pharmacokinetic comparisons against shorter-acting analogues typically use the With-DAC form, because the days-long half-life produces a fundamentally different exposure pattern.
Verifying which form you have
Because the two forms share the same base sequence and differ only in a single modification, HPLC purity testing alone cannot reliably distinguish them — both will elute as peaks at similar (but not identical) retention times. The verification step is Mass Spectrometry: the maleimidopropionyl modification adds a specific, documented mass shift. A high-quality Certificate of Analysis for CJC-1295 explicitly states the form (With-DAC or No-DAC) and includes the MS result confirming presence or absence of the modification.
View CJC-1295 No-DAC 5mg
Independently HPLC + MS tested at 99%+ purity. Each batch's COA explicitly documents the No-DAC form.
Frequently asked questions
Frequently Asked Questions
Functionally, yes — both forms engage the GHRH receptor with the same base sequence. The DAC modification's effect is to extend half-life by enabling covalent albumin binding. So in receptor-pharmacology terms, the two are similar; in pharmacokinetic terms, they are very different.
No. The half-life difference is large enough — hours vs days — that protocols designed around one form cannot be directly translated to the other without rethinking dosing cadence and exposure assumptions.
Each batch of CJC-1295 No-DAC is sent to an independent third-party laboratory for HPLC and Mass Spectrometry analysis. The Mass Spec result explicitly confirms that the maleimidopropionyl modification of the DAC version is not present. The Certificate of Analysis documents both the HPLC purity percentage and the MS form-confirmation.
CJC-1295 No-DAC engages the GHRH receptor; Ipamorelin engages the ghrelin / growth-hormone-secretagogue receptor. These are two complementary entry points into the growth-hormone axis, and research protocols frequently use them together to study pathway interaction. The No-DAC form's shorter half-life is well-matched to Ipamorelin's similarly short half-life, which simplifies coordinated dosing in research designs.
