CJC-1295 is available in two distinct formulations that, despite sharing a name and base sequence, behave very differently in research models: CJC-1295 with DAC (Drug Affinity Complex) and CJC-1295 without DAC. The difference between them is not merely a matter of modification — it represents a fundamental difference in pharmacokinetic profile that has significant implications for experimental design.
Understanding the distinction between these two formulations is essential for researchers working with growth hormone secretagogue models. This guide examines the molecular basis of the DAC modification, how it affects the compound’s behavior in research applications, and what researchers should consider when selecting between the two formulations.
| Property | CJC-1295 No DAC | CJC-1295 DAC |
|---|---|---|
| Also known as | Modified GRF(1-29), Mod GRF 1-29 | CJC-1295 |
| DAC modification | No | Yes (lysine-maleimide conjugate) |
| Half-life | ~30 minutes | ~6–8 days |
| GH release pattern | Pulsatile | Sustained/continuous |
| Molecular weight | 3,367.97 g/mol | 3,647.28 g/mol |
| CAS number | 863288-34-0 | 863288-34-0 |
| Albumin binding | No | Yes |
| Purity (Official Peptides) | >99% HPLC | >99% HPLC |
| Storage | -20°C lyophilized | -20°C lyophilized |
CJC-1295 is a synthetic analogue of growth hormone releasing hormone (GHRH) — the hypothalamic peptide that stimulates pituitary release of growth hormone (GH). Native GHRH is a 44-amino acid peptide with a very short half-life in circulation, due to rapid degradation by dipeptidyl peptidase-4 (DPP-4) and other proteolytic enzymes.
CJC-1295 was developed to address this limitation. The base compound — a 29-amino acid GHRH analogue — incorporates several amino acid substitutions that confer resistance to DPP-4 degradation, extending its effective half-life relative to native GHRH. This base compound is what researchers refer to as CJC-1295 No DAC (or Modified GRF 1-29).
The DAC formulation takes this further by conjugating a Drug Affinity Complex — a maleimide-modified lysine residue — to the peptide. This modification enables the compound to covalently bind to circulating albumin, the most abundant protein in plasma, dramatically extending its half-life from approximately 30 minutes to 6-8 days.
The Drug Affinity Complex (DAC) modification is a chemical addition that fundamentally changes the pharmacokinetic behavior of CJC-1295. Understanding how it works explains why the two formulations produce such different research outcomes.
The maleimide group added to the lysine residue of CJC-1295 DAC reacts with the free thiol group of cysteine-34 on serum albumin — forming a stable covalent bond. This albumin-binding mechanism is the same principle exploited by several pharmaceutical drugs to extend their half-life.
Once bound to albumin, CJC-1295 DAC is protected from proteolytic degradation and renal clearance — the two primary mechanisms responsible for peptide elimination from circulation. The albumin complex acts as a reservoir, slowly releasing the active peptide over an extended period. The result is a half-life of 6-8 days versus approximately 30 minutes for the non-DAC formulation.
The half-life difference between CJC-1295 No DAC and CJC-1295 DAC is not merely a pharmacokinetic detail — it has fundamental implications for the type of GH secretion pattern produced in research models and therefore for the experimental questions each formulation can address.
CJC-1295 No DAC produces pulsatile GH release — consistent with the physiological pattern of GH secretion, which occurs in discrete pulses primarily during sleep. This makes No DAC the appropriate formulation for researchers studying pulsatile GH secretion models, circadian GH rhythms, or experimental contexts where discrete GH pulses are the relevant variable.
CJC-1295 DAC produces sustained, continuous GH elevation — a fundamentally different secretion pattern that does not replicate physiological GH pulsatility. This makes DAC appropriate for researchers studying the effects of sustained GH elevation, continuous GHRH receptor stimulation, or experimental models where maintained GH levels are the relevant variable.
Pulsatile GH secretion models — CJC-1295 No DAC is the appropriate formulation for research examining pulsatile GH release. Its short half-life produces discrete GH pulses in experimental models, making it suitable for studies examining the physiological pattern of GH secretion and its downstream effects.
Acute GH axis research — Studies examining the acute response of the GH axis to GHRH stimulation — including pituitary responsiveness, GH pulse amplitude, and immediate downstream signaling — are better served by No DAC’s discrete, measurable GH pulses.
Combination research with ghrelin mimetics — CJC-1295 No DAC is frequently co-administered with ghrelin receptor agonists (including Ipamorelin and GHRP-6) in research models examining synergistic GH release. The short half-life of No DAC makes it more tractable for precisely timed combination dosing protocols.
Circadian rhythm research — Research examining the relationship between GH pulsatility and circadian biology is better served by No DAC, which can be administered at specific time points to replicate or modulate the physiological pattern of nocturnal GH pulses.
Sustained GH elevation models — CJC-1295 DAC is the appropriate formulation for research requiring maintained GH elevation over extended periods. Its 6-8 day half-life produces a steady-state GH elevation without the pulsatile pattern of the No DAC formulation.
IGF-1 axis research — Studies examining sustained effects on IGF-1 (insulin-like growth factor 1) levels — GH’s primary downstream mediator — are better served by DAC’s extended GH elevation. Research examining the relationship between chronic GH elevation and IGF-1 expression has predominantly used the DAC formulation.
Long-duration experimental protocols — Research programs examining the effects of GH elevation over weeks or months can be conducted more efficiently with CJC-1295 DAC, which requires less frequent administration to maintain target GH levels than No DAC.
Albumin binding research — CJC-1295 DAC’s unique albumin-binding mechanism makes it a useful tool compound for researchers studying drug delivery systems, albumin-mediated pharmacokinetics, or the biology of albumin as a drug carrier.
Both CJC-1295 formulations are frequently studied in combination with ghrelin receptor agonists — particularly Ipamorelin and GHRP-6. The rationale for combined use is mechanistic: GHRH (via CJC-1295) and ghrelin agonists (via ghrelin receptor activation) act through complementary pathways that, when combined, produce synergistic GH release greater than either compound alone.
Research examining CJC-1295 + Ipamorelin combinations has documented amplified GH release relative to either compound administered alone — findings that have made this combination one of the most studied in GH secretagogue research.
For combination research:
– CJC-1295 No DAC is typically preferred for precisely timed combination protocols, given its short half-life and predictable pulsatile release pattern
– CJC-1295 DAC may be used in longer-duration combination studies where sustained GH background elevation is the experimental goal
The choice between CJC-1295 No DAC and CJC-1295 DAC should be driven by the specific experimental question and the GH secretion pattern relevant to the research model.
Choose CJC-1295 No DAC when:
– The research question involves pulsatile GH release
– The study design requires precise control over GH pulse timing
– The experimental model involves combination dosing with ghrelin receptor agonists
– The focus is on acute GH axis response to GHRH stimulation
– The research context involves circadian GH biology
Choose CJC-1295 DAC when:
– The research question involves sustained GH elevation
– The study design requires maintained GH levels over extended periods
– The experimental model examines chronic effects on IGF-1 or downstream GH signaling
– The research involves albumin-binding pharmacokinetics
– The protocol duration makes frequent No DAC administration impractical
Consider both when:
– The research program spans multiple experimental questions requiring different GH secretion patterns
– Comparative pharmacokinetic studies are part of the research design
– The laboratory is establishing a comprehensive GH axis research toolkit
CJC-1295 No DAC’s short half-life requires more frequent administration in research protocols than CJC-1295 DAC. Researchers designing long-duration experiments should factor this into protocol planning — including the practical implications for experimental consistency and researcher workload.
Both formulations should be sourced at >99% purity by HPLC. For CJC-1295 DAC specifically, purity verification should include confirmation that the DAC modification is present and intact — mass spectrometry analysis alongside HPLC purity testing provides the most complete quality picture.
Both formulations reconstitute well in sterile bacteriostatic water and should be stored at -20°C in lyophilized form. Reconstituted solutions should be stored at 4°C and used within 14 days (No DAC) or 30 days (DAC). Aliquoting reconstituted solutions is recommended for both formulations to minimize freeze-thaw cycles.
Official Peptides supplies both CJC-1295 No DAC and CJC-1295 DAC at >99% purity, independently verified by third-party HPLC analysis. Batch-specific certificates of analysis are published for every production run and accessible via the COA viewer on each product page. Researchers requiring both formulations can source from a single verified supplier with consistent quality documentation.
What does DAC stand for in CJC-1295 DAC?
DAC stands for Drug Affinity Complex — a maleimide-modified lysine residue conjugated to the CJC-1295 peptide that enables it to covalently bind to circulating albumin, dramatically extending its half-life from approximately 30 minutes to 6-8 days.
Which CJC-1295 formulation is more commonly used in research?
Both formulations are extensively used, but CJC-1295 No DAC (Modified GRF 1-29) appears more frequently in combination studies with ghrelin receptor agonists such as Ipamorelin. CJC-1295 DAC is more commonly used in longer-duration studies requiring sustained GH elevation.
Can CJC-1295 No DAC and DAC be used together in research?
While theoretically possible, combining the two formulations in the same experimental model is uncommon in the published literature. Most research uses one formulation or the other depending on the GH secretion pattern required for the experimental design.
Is CJC-1295 No DAC the same as Modified GRF 1-29?
Yes. CJC-1295 No DAC and Modified GRF (1-29) refer to the same compound — a 29-amino acid GHRH analogue with amino acid substitutions conferring DPP-4 resistance, without the albumin-binding DAC modification.
What purity should research-grade CJC-1295 be?
For both formulations, >99% purity by HPLC is the appropriate standard for research applications. For CJC-1295 DAC, confirmation of the intact DAC modification via mass spectrometry provides additional quality assurance beyond purity alone.
Where can I source both CJC-1295 formulations for research?
Official Peptides supplies both CJC-1295 No DAC and CJC-1295 DAC at >99% purity with independent third-party verification and batch-specific COA documentation. Both are available in 2mg and 5mg vials.
CJC-1295 No DAC and CJC-1295 DAC are distinct research tools that address different experimental questions. The DAC modification’s effect on half-life — from 30 minutes to 6-8 days — produces fundamentally different GH secretion patterns in research models, making the formulation choice a critical experimental design decision rather than a minor detail.
Researchers studying pulsatile GH release, acute GHRH axis response, or combination protocols with ghrelin receptor agonists should select CJC-1295 No DAC. Researchers studying sustained GH elevation, chronic IGF-1 effects, or long-duration experimental protocols should select CJC-1295 DAC.
Official Peptides supplies both formulations at >99% purity with independent third-party verification and published batch-specific COA documentation.
→ View CJC-1295 No DAC product page
→ View CJC-1295 DAC product page
This content is authored by Priya Anand, Research Scientist specialising in endocrinology and metabolic peptide research. All information is provided for research reference purposes only. CJC-1295 is not approved for human use and is not intended for diagnostic or therapeutic purposes. For in vitro laboratory research use only.
All content is provided for research reference purposes only. For in vitro laboratory research use only.