CJC-1295 DAC vs No DAC: What’s the Difference? (2026 Guide)
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CJC-1295 DAC vs No DAC: Understanding the Difference
CJC-1295 is a synthetic analog of growth hormone-releasing hormone (GHRH) with a modified structure that extends its biological half-life. It exists in two primary forms: CJC-1295 with DAC (Drug Affinity Complex) and CJC-1295 without DAC (also called Modified GRF 1-29 or MOD-GRF). The distinction between these two variants is one of the most common points of confusion among peptide researchers. This article clarifies the differences in structure, pharmacokinetics, and research applications.
What Is the DAC (Drug Affinity Complex)?
The Drug Affinity Complex is a lysine-linked maleimidopropionic acid residue that binds covalently to serum albumin after injection. This albumin binding dramatically extends the peptide's circulating half-life from minutes to days. CJC-1295 with DAC was originally developed by ConjuChem Biotechnologies (now Corcept Therapeutics) for potential clinical applications requiring sustained GH elevation.
Pharmacokinetic Comparison
| Property | CJC-1295 with DAC | CJC-1295 without DAC (MOD-GRF 1-29) |
|---|---|---|
| Half-life | 6–8 days | ~30 minutes |
| GH Elevation Pattern | Sustained, continuous elevation | Pulsatile, acute spikes |
| Peak GH Levels | Moderate sustained increase | Higher acute peaks |
| Dosing Frequency in Research | 1–2x per week | 1–3x daily |
| Albumin Binding | Yes — covalent albumin binding | No |
| GH Bleed (Continuous Elevation) | Yes — a key research consideration | No — mimics natural pulsatile release |
Why the Distinction Matters for Research
Pulsatile vs Sustained GH Release
The body's natural growth hormone secretion follows a pulsatile pattern — sharp peaks followed by return to baseline, primarily during sleep. This pulsatile pattern is believed to be important for maintaining GH receptor sensitivity and optimal downstream signaling through IGF-1.
CJC-1295 without DAC (MOD-GRF 1-29) mimics this natural pulsatile pattern. Its short half-life means it stimulates a GH pulse and then clears, allowing GH levels to return to baseline. This is why it's frequently paired with Ipamorelin — the combination produces a synergistic GH pulse without disrupting the natural rhythm.
CJC-1295 with DAC, by contrast, produces sustained GH elevation over days. While this means less frequent dosing in research protocols, the continuous elevation (sometimes called "GH bleed") does not replicate the body's natural pulsatile release pattern. This has implications for receptor desensitization research.
The CJC-1295 + Ipamorelin Combination
The most widely researched combination uses CJC-1295 without DAC (MOD-GRF 1-29) paired with Ipamorelin, a selective growth hormone secretagogue. The rationale for this combination is that CJC-1295 no DAC stimulates GHRH receptors while Ipamorelin stimulates ghrelin receptors (GHS-R), producing a synergistic GH release that's greater than either compound alone while maintaining the natural pulsatile pattern.
ThePeptide.ca's CJC-1295 + Ipamorelin 10mg blend uses the no-DAC variant (MOD-GRF 1-29) specifically because it enables pulsatile GH research protocols.
Research Applications
| Application | With DAC | Without DAC (MOD-GRF) |
|---|---|---|
| GH pulsatility research | Less suitable — sustained elevation | Preferred — mimics natural pattern |
| Long-duration protocols | Convenient — less frequent dosing | Requires more frequent administration |
| Combination with GHRP/GHS | Less common | Standard — paired with Ipamorelin or GHRP-6 |
| Receptor sensitivity studies | Risk of desensitization from sustained elevation | Lower risk due to clearance between doses |
| Sleep-cycle GH research | Less applicable | Well-suited — can time pulses |
Key Research Citations
- Teichman SL, et al. "Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295." J Clin Endocrinol Metab. 2006. PMID: 16368745
- Alba M, et al. "Once-daily administration of CJC-1295, a long-acting growth hormone-releasing hormone (GHRH) analog." J Clin Endocrinol Metab. 2006. PMID: 16352683
- Raun K, et al. "Ipamorelin, the first selective growth hormone secretagogue." Eur J Endocrinol. 1998. PMID: 9725779
Source Research-Grade CJC-1295 + Ipamorelin in Canada
ThePeptide.ca provides a pre-blended CJC-1295 (no DAC) + Ipamorelin 10mg formulation for Canadian researchers. All products are third-party tested via HPLC at Testides with published COAs and a 99% minimum purity guarantee.