“CJC-1295 with DAC” and “CJC-1295 without DAC” are often treated as two versions of one compound. The literature supports a more careful distinction.
Research-use notice: This article is an educational review of published research and analytical terminology. It is not medical advice, a treatment guide, or an administration protocol. The compounds discussed are not presented for human or veterinary use.
The phrase “CJC-1295 with DAC vs without DAC” appears simple, but the terminology can hide an important scientific problem. CJC-1295 was developed as a long-acting analogue of growth hormone-releasing hormone (GHRH). Its extended action depends in part on a reactive Drug Affinity Complex (DAC) group that can form a covalent bond with circulating albumin. By contrast, material sold as “CJC-1295 without DAC” is commonly identified as modified GRF(1-29), a shorter GHRH analogue that does not contain the albumin-binding extension.
Those labels are not interchangeable. A laboratory comparing the compounds must distinguish their complete sequences, terminal modifications, molecular masses and expected time courses before interpreting any biological result.
Quick comparison
| Research feature | CJC-1295 with DAC | “CJC-1295 without DAC” / modified GRF(1-29) |
|---|---|---|
| Common literature identity | CJC-1295; DAC:GRF | Modified GRF(1-29), often shortened commercially to “no-DAC” |
| Core design | Protease-resistant GHRH(1-29) analogue plus albumin-binding DAC extension | Protease-resistant GHRH(1-29) analogue without an albumin-binding extension |
| Primary receptor system | GHRH receptor | GHRH receptor |
| Pharmacokinetic concept | Albumin association extends systemic exposure | Shorter exposure relative to the DAC construct |
| Best-supported published evidence | Animal pharmacology and small human pharmacokinetic/pharmacodynamic studies | GHRH-analogue and sequence-level literature; commercial naming is less standardized |
| Main laboratory risk | Assuming every product called CJC-1295 has the DAC construct | Assuming “no-DAC” is a universally defined scientific name |
| Minimum identity check | Sequence, exact mass and DAC-related modification | Sequence, exact mass and terminal state |
What is CJC-1295 with DAC?
CJC-1295 was designed from the biologically active 1–29 region of human GHRH. Four substitutions were introduced to improve resistance to enzymatic degradation. The molecule also carries a maleimide-containing extension that reacts with a free thiol on serum albumin. In the original development literature, this albumin bioconjugation strategy was intended to reduce rapid clearance and create a longer-acting research molecule.
Jetté and colleagues described the selection of CJC-1295 from albumin-binding GHRH analogues in rat studies. Their work showed that the construct retained GHRH-receptor activity while producing an extended pharmacodynamic response. A later randomized study by Teichman and colleagues examined CJC-1295 in healthy adults and reported sustained increases in measured growth hormone and insulin-like growth factor I after administration. A separate analysis by Ionescu and Frohman reported that growth-hormone pulsatility remained detectable during the period of increased exposure.
These studies define what the name CJC-1295 meant in its formal development program: a specific modified GHRH sequence with an albumin-binding DAC component. They do not establish that every vial carrying the same commercial name contains that exact construct.
What does “CJC-1295 without DAC” mean?
In commercial research catalogues, “CJC-1295 without DAC” usually refers to a peptide also called modified GRF(1-29). It contains the stabilizing substitutions associated with the GHRH analogue but omits the albumin-binding extension used in formal CJC-1295.
The label is convenient, but scientifically imprecise. Removing a functional extension from a named development compound does not automatically create a standardized second compound name. Different suppliers may use “CJC-1295 no DAC,” “modified GRF(1-29),” “mod GRF” or another shorthand. A product name alone therefore cannot establish:
- the complete amino-acid sequence;
- whether the peptide is amidated;
- whether an extra lysine or linker is present;
- the expected monoisotopic or average molecular mass;
- the salt or counter-ion form; or
- the presence or absence of related synthesis products.
For research planning, the sequence and analytical identity should take priority over the catalogue label.
Why the DAC changes the experimental question
1. Albumin binding changes exposure
The DAC construct was created to bind albumin in circulation. This turns a short GHRH analogue into a longer-exposure research probe. The biological question is no longer limited to whether the peptide activates the GHRH receptor; it also includes how prolonged systemic exposure changes downstream signaling and hormone patterns.
2. Peak and integrated exposure are different variables
Two compounds can interact with the same receptor but generate different time–concentration profiles. A short exposure may create a transient signal, while an albumin-associated construct can change the duration and total area under the concentration curve. Comparing nominal mass alone can therefore produce a misleading interpretation.
3. Matrix choice becomes more important
Albumin concentration differs among purified receptor systems, cell culture media, ex vivo preparations and intact-animal models. A DAC-containing molecule may behave differently in an albumin-free assay than in a plasma-containing system. Researchers should document albumin content and other matrix proteins when comparing the two materials.
4. Analytical methods may need different acceptance criteria
A mass-spectrometry method built for modified GRF(1-29) should not be assumed to identify CJC-1295 with DAC. The expected molecular mass, fragmentation pattern and retention behaviour differ. The albumin-reactive group also introduces handling considerations that do not apply to the shorter analogue.
What the published evidence does—and does not—show
The strongest direct human evidence for formal CJC-1295 comes from small, early pharmacokinetic and pharmacodynamic studies published in 2006. They measured growth hormone and IGF-I responses and investigated the persistence of pulsatile secretion. These studies help characterize the development compound, but they do not answer every current research question.
Important limitations include:
- small participant samples;
- short observation windows compared with long-term clinical outcomes;
- emphasis on biomarkers rather than therapeutic endpoints;
- a specific sponsor-manufactured compound rather than today’s many catalogue materials; and
- no basis for treating an unverified research vial as equivalent to the material used in those trials.
Evidence for “CJC-1295 without DAC” is harder to summarize because the commercial name is inconsistent. Some mechanistic expectations can be derived from modified GHRH(1-29) chemistry and receptor pharmacology, but those expectations should not be presented as proof that two independently sourced materials are identical.
A rigorous comparison framework
A defensible laboratory comparison starts with material identity and works forward to biology.
Confirm the exact molecule
Record the full sequence, terminal modifications, theoretical mass, counter-ion and lot number. Avoid study records that identify a sample only as “CJC.”
Verify identity separately from purity
High-performance liquid chromatography can estimate the relative abundance of chromatographic components, but a high area percentage does not prove that the main peak is the intended peptide. Pair chromatographic purity with an identity method such as mass spectrometry. Review our Peptide COA Guide for the distinction between identity and purity evidence.
Match the matrix to the hypothesis
If albumin binding is central to the hypothesis, document albumin concentration and source. If the goal is direct receptor comparison, consider how the assay isolates receptor activation from exposure effects.
Use time-resolved sampling
A single endpoint can miss the defining difference between short and prolonged exposure. Predefine time points that can capture onset, peak, decline and downstream response. The correct schedule depends on the assay and is not inferred from a commercial label.
Include appropriate controls
Useful controls may include vehicle, a reference GHRH ligand, matrix-only controls and independently characterized reference material. The exact control set should be justified by the model.
Report the compound without shorthand
In methods and figure legends, state the sequence-level identity and whether the DAC extension is present. This makes the work reproducible even when catalogue terminology changes.
Common interpretation errors
Treating “with DAC” and “without DAC” as dose variants
They are structurally different research materials, not merely different strengths of one formulation.
Using half-life claims without specifying the model
Half-life depends on the measured analyte, species, route, matrix and analytical method. A value from a human pharmacokinetic study cannot simply be transferred to a cell assay or another species.
Assuming a purity percentage confirms identity
An HPLC area percentage can be high even when the dominant peak is the wrong peptide. Exact-mass and sequence-related evidence remain essential.
Extending clinical biomarker findings to research products
Published human studies used a defined development material under controlled conditions. They do not validate an unrelated supplier’s product, establish suitability for personal use or substitute for regulatory approval.
Frequently asked questions
Is CJC-1295 without DAC the same as modified GRF(1-29)?
That is the most common commercial usage, but the name alone is not enough. Confirm the complete sequence, terminal modifications and exact mass on the product specification and lot-matched analytical record.
Do both materials act through the same receptor system?
Both are designed around GHRH-receptor agonism. Their exposure profiles differ because the DAC-containing construct can associate with albumin. Assay design determines whether that difference is visible.
Does DAC mean “long acting” in every experiment?
Not automatically. The observed effect depends on albumin availability, matrix composition, model and sampling schedule. A purified assay without relevant binding partners may not reproduce an intact-system exposure profile.
Can one COA template be used for both compounds?
The reporting format may be shared, but the expected sequence, molecular mass and method suitability must be compound-specific. A generic “CJC-1295” result is not sufficiently descriptive.
Are these compounds approved for human use in Canada?
This article does not describe an approved therapeutic use. Research materials should not be treated as authorized drug products, and a research label does not establish safety, efficacy or suitability for administration.
Bottom line
The key difference is not simply “DAC versus no DAC.” Formal CJC-1295 is an albumin-binding GHRH analogue with a defined development history. The material commonly sold as “CJC-1295 without DAC” is usually modified GRF(1-29), but commercial terminology is inconsistent. Good research practice therefore begins with sequence-level identity, fit-for-purpose analytics and a design that can resolve exposure over time.
For broader quality controls, see the Research Library and the Peptide Storage and Handling Guide.
References
- Jetté L, et al. Human growth hormone-releasing factor (hGRF)1-29-albumin bioconjugates activate the GRF receptor on the anterior pituitary in rats: identification of CJC-1295 as a long-lasting GRF analog. Endocrinology. 2005;146(7):3052–3058. doi:10.1210/en.2004-1286. PMID: 15817669.
- Teichman SL, et al. Prolonged stimulation of growth hormone and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults. J Clin Endocrinol Metab. 2006;91(3):799–805. doi:10.1210/jc.2005-1536. PMID: 16352683.
- Ionescu M, Frohman LA. Pulsatile secretion of growth hormone persists during continuous stimulation by CJC-1295, a long-acting GHRH analog. J Clin Endocrinol Metab. 2006;91(12):4792–4797. doi:10.1210/jc.2006-1702. PMID: 17018654.
- Memdouh S, Gavrilović I, Ng K, Cowan D, Abbate V. Advances in the detection of growth hormone releasing hormone synthetic analogs. Drug Test Anal. 2021;13(11–12):1871–1887. doi:10.1002/dta.3183. PMID: 34665524.