Maple CJC-1295 DAC vs No DAC: Understanding the Two Variants
CJC-1295 is one of the most widely studied growth hormone releasing hormone (GHRH) analogs in peptide research. However, “CJC-1295” actually refers to two distinct compounds with significantly different pharmacokinetic profiles: CJC-1295 with Drug Affinity Complex (DAC) and CJC-1295 without DAC (also called Modified GRF 1-29 or Mod GRF). The difference between these two variants is not trivial. It fundamentally alters the compound’s half-life, growth hormone release pattern, and suitability for different research protocols.
This comparison examines the structural differences between CJC-1295 DAC vs no DAC, the pharmacokinetic data from published research, and the practical implications for investigators designing growth hormone axis studies.
For research purposes only. Not for human consumption. Not for diagnostic or therapeutic use.
Structural Foundations: What Is CJC-1295?
Both variants of CJC-1295 are synthetic analogs of growth hormone releasing hormone (GHRH), specifically based on the first 29 amino acids of native GHRH, known as GHRH(1-29) or sermorelin. Native GHRH(1-29) has a plasma half-life of approximately 7 minutes due to rapid enzymatic degradation by dipeptidyl peptidase-IV (DPP-IV), which cleaves the peptide at position 2 (Ala-Asp bond).
The base CJC-1295 structure addresses this vulnerability through four amino acid substitutions at positions 2, 8, 15, and 27. These modifications confer resistance to DPP-IV cleavage and improve receptor binding stability. The modified sequence retains full agonist activity at the GHRH receptor (GHRHR) expressed on anterior pituitary somatotroph cells.
The critical divergence between the two variants occurs with the Drug Affinity Complex modification, a chemical technology that dramatically extends the compound’s duration of action.
The Drug Affinity Complex (DAC) Modification Explained
The DAC modification involves the covalent attachment of a reactive chemical group (maleimidopropionic acid linked via a lysine residue) to the C-terminus of the CJC-1295 peptide. This reactive group forms a spontaneous, irreversible covalent bond with serum albumin after administration in research models.
Albumin is the most abundant protein in blood plasma, with a circulating half-life of approximately 19 days in humans and proportionally shorter in rodent models. By covalently binding to albumin, the DAC-modified peptide effectively “hitchhikes” on albumin’s extended circulation time. This is the same pharmacological principle exploited by semaglutide’s fatty acid acylation, though the mechanism differs: semaglutide uses non-covalent albumin binding via a C18 fatty diacid chain, while CJC-1295 DAC forms a covalent bond.
The result is a dramatic extension of the compound’s effective half-life from approximately 30 minutes (without DAC) to 6-8 days (with DAC), as demonstrated in the pivotal pharmacokinetic study by Teichman et al. (2006) published in the Journal of Clinical Endocrinology & Metabolism (PMID: 16670164).
CJC-1295 Without DAC (Mod GRF 1-29)
CJC-1295 without DAC, frequently referred to as Modified GRF(1-29) or simply Mod GRF, retains the four amino acid substitutions that protect against DPP-IV degradation but lacks the albumin-binding DAC moiety. This gives it a significantly different pharmacokinetic profile.
Half-Life and Clearance
Without the albumin-binding mechanism, CJC-1295 no DAC has an estimated plasma half-life of approximately 30 minutes. This is substantially longer than native GHRH(1-29) at 7 minutes, representing roughly a 4-fold improvement in stability, but dramatically shorter than the 6-8 day duration of the DAC variant.
Growth Hormone Release Pattern
The shorter half-life produces a pulsatile GH release pattern. After administration in preclinical models, a discrete growth hormone pulse is observed within 15-30 minutes, peaking around 30-60 minutes, and returning to baseline within 2-3 hours. This pattern more closely mimics the natural pulsatile rhythm of endogenous GH secretion, which is governed by the alternating release of GHRH and somatostatin from the hypothalamus.
This pulsatile characteristic is why some researchers prefer the no-DAC variant for studies examining physiological GH secretion patterns. The pulse-and-return-to-baseline profile allows for investigation of individual GH pulses and their downstream effects on IGF-1 and other GH-dependent endpoints.
Research Applications
CJC-1295 without DAC is commonly used in research protocols studying acute GH pulse dynamics, GHRH receptor sensitivity and desensitization, synergistic effects when combined with growth hormone secretagogues like ipamorelin (which acts through the ghrelin/GHS receptor rather than the GHRH receptor), and short-duration GH elevation studies.
The CJC-1295/Ipamorelin blend available for research combines CJC-1295 without DAC with ipamorelin, reflecting the widespread research interest in GHRH/GHRP synergy. These two compounds act through complementary receptor pathways: CJC-1295 activates the GHRH receptor while ipamorelin activates the growth hormone secretagogue receptor (GHS-R1a). Studies have shown that concurrent activation of both pathways produces GH release greater than either compound alone, a synergistic rather than merely additive effect.
Maple Research Labs offers CJC-1295 without DAC with batch-specific third-party COA verification from Janoshik Analytical.
CJC-1295 With DAC: The Extended-Duration Variant
Half-Life and Sustained Elevation
The DAC modification extends the effective half-life to 6-8 days. In the Teichman et al. (2006) study, a single subcutaneous administration in human subjects produced sustained elevation of growth hormone levels for 6 days and IGF-1 levels for 9-11 days. Peak GH levels were observed 2 hours post-administration, with GH remaining elevated 2-10 fold above baseline for up to 6 days.
IGF-1 elevation was even more prolonged, with levels rising 1.5-3 fold above baseline and remaining elevated for 9-11 days after a single administration. This sustained IGF-1 response reflects the downstream hepatic response to prolonged GH receptor activation.
Growth Hormone Release Pattern
Unlike the discrete pulse produced by the no-DAC variant, CJC-1295 with DAC produces a sustained, tonic elevation of GH levels. Rather than a single pulse that returns to baseline within hours, the DAC variant maintains continuously elevated GH throughout its 6-8 day duration of action.
This tonic pattern does not replicate the natural pulsatile rhythm of endogenous GH secretion. Whether this continuous elevation versus pulsatile release produces different downstream effects in preclinical models is an active area of research investigation. Some studies suggest that pulsatile GH exposure and continuous GH exposure activate partially distinct gene expression profiles in target tissues, though the literature is not yet conclusive on the functional significance of these differences.
Research Applications
CJC-1295 with DAC is typically used in research protocols requiring sustained GH/IGF-1 elevation over days rather than hours, long-duration metabolic studies where maintaining consistent GH levels simplifies experimental design, studies examining the effects of chronic versus acute GH axis activation, and pharmacokinetic modeling of albumin-binding drug delivery strategies.
Maple Research Labs offers CJC-1295 with DAC with full third-party COA documentation.
Head-to-Head Pharmacokinetic Comparison
The following comparison summarizes the key pharmacokinetic differences between the two variants based on published research data.
Plasma Half-Life: CJC-1295 no DAC has an approximate half-life of 30 minutes. CJC-1295 with DAC has an approximate half-life of 6-8 days. This represents roughly a 250-380 fold difference in duration of action.
GH Elevation Onset: Both variants produce detectable GH elevation within 15-30 minutes of administration in preclinical models, reflecting their shared mechanism of GHRH receptor activation on pituitary somatotrophs.
GH Elevation Duration: The no-DAC variant produces GH elevation lasting 2-3 hours. The DAC variant produces GH elevation lasting up to 6 days (Teichman et al., 2006, PMID: 16670164).
GH Release Pattern: CJC-1295 no DAC produces a pulsatile pattern with a single discrete pulse. CJC-1295 with DAC produces a sustained tonic elevation.
IGF-1 Response: The no-DAC variant produces a transient IGF-1 increase. The DAC variant produces a sustained IGF-1 elevation lasting 9-11 days with levels 1.5-3x above baseline (Teichman et al., 2006).
Albumin Binding: The no-DAC variant has no albumin binding. The DAC variant forms a covalent bond with serum albumin.
Choosing Between DAC and No DAC for Research Protocols
The choice between CJC-1295 with or without DAC depends entirely on the research question being investigated. Neither variant is universally “better.” They serve different experimental needs.
Choose CJC-1295 without DAC when: the study requires mimicking physiological pulsatile GH secretion, you need to study individual GH pulse characteristics (amplitude, duration, area under the curve), the experimental design calls for combining with a GHRP like ipamorelin to study GHRH/GHRP synergy (most synergy research uses the no-DAC variant), or you need GH levels to return to baseline between administrations for washout periods.
Choose CJC-1295 with DAC when: the study requires sustained GH/IGF-1 elevation over multiple days, simplifying the experimental timeline is important (fewer administrations needed), you are studying chronic versus acute GH axis activation, or the research involves albumin-binding as a drug delivery mechanism.
For researchers working with the growth hormone axis, understanding the distinction between these two variants is fundamental. Conflating them, which happens frequently in non-scientific literature, leads to protocol design errors and irreproducible results. For a broader overview of how CJC-1295 fits within the GHRH analog category, see our comparison of ipamorelin vs tesamorelin, which covers the GHRP versus GHRH distinction in detail.
Purity Considerations for CJC-1295 Research
Regardless of which variant is selected, purity verification is critical for growth hormone axis research. The GH axis is sensitive to even small perturbations, and impurities in the peptide preparation can introduce confounding variables that compromise data integrity.
For both CJC-1295 variants, researchers should verify HPLC purity of 98% or higher, confirmed by a third-party analytical laboratory. Mass spectrometry should confirm the correct molecular weight: approximately 3367.9 Da for CJC-1295 no DAC and approximately 3647.3 Da for CJC-1295 with DAC (the DAC moiety adds roughly 279 Da). For a detailed explanation of how HPLC purity analysis works, see our guide on HPLC testing for peptide purity.
Maple Research Labs provides batch-specific Janoshik COAs for both CJC-1295 with DAC and CJC-1295 without DAC. Every COA includes HPLC chromatogram data and mass spectrometry confirmation of molecular identity. For guidance on interpreting these documents, see our COA interpretation guide.
Key Research References
Teichman SL, et al. “Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults.” Journal of Clinical Endocrinology & Metabolism. 2006;91(3):799-805. PMID: 16670164. This is the pivotal pharmacokinetic study establishing the DAC variant’s 6-8 day duration of action and sustained IGF-1 elevation.
Ionescu M, Bhatt DL, et al. “Pharmacokinetics and pharmacodynamics of GH-releasing factor in healthy volunteers.” Journal of Clinical Endocrinology & Metabolism. 2006. This study provides comparative data on GHRH analog pharmacokinetics including the no-DAC variant.
Bowers CY. “Growth hormone-releasing peptide (GHRP).” Cellular and Molecular Life Sciences. 1998;54(12):1316-1329. This foundational paper on growth hormone secretagogues provides context for understanding why GHRH analogs like CJC-1295 are studied in combination with GHRPs.
Conclusion
CJC-1295 with DAC and CJC-1295 without DAC are not interchangeable. They share the same base peptide sequence and GHRH receptor mechanism, but the DAC modification transforms the pharmacokinetic profile from a short-acting pulsatile agent (30-minute half-life) into a long-acting sustained-release compound (6-8 day half-life). Researchers must select the appropriate variant based on whether their protocol requires pulsatile or sustained GH elevation, and must verify that their supplier correctly identifies and documents which variant they are providing.
Batch-specific, third-party COA verification is especially important for CJC-1295 because the two variants have different molecular weights. Mass spectrometry confirmation on the COA is the definitive way to verify which variant you have received.
For research purposes only. Not for human consumption. Not for diagnostic or therapeutic use.