Peptides: CJC-1295 Overview (DAC vs No-DAC)
CJC-1295 with DAC produced sustained IGF-1 elevation over 14 days in healthy adults (PMID 16368745). The no-DAC form preserves pulsatile GH secretion, preferred for most protocols.
| Measure | Value | Unit | Notes |
|---|---|---|---|
| Evidence Grade | B | grade | Human pharmacokinetic data for both forms (PMID 16968793; 16368745); no body composition RCTs at performance protocol doses |
| CJC-1295 with DAC — Half-life | 6–8 | days | Drug Affinity Complex (DAC) modification enables albumin binding; dramatically extends circulating half-life |
| CJC-1295 without DAC — Half-life | ~30 | minutes (subcut) | Also called Mod GRF 1-29; 29-amino acid GHRH analogue; short half-life preserves pulsatile GH pattern |
| IGF-1 Elevation (DAC form) | 1.5–3× | above baseline | Sustained IGF-1 elevation maintained for 14+ days with weekly DAC injections (PMID 16368745); blunts pulsatility |
| Standard No-DAC Dose | 100–200 | mcg/injection | Injected simultaneously with GHRP; 2–3× daily; timing must match GHRP injection exactly |
| Standard DAC Dose | 1–2 | mg/injection | Once or twice weekly; much larger per-dose due to sustained-release kinetics; NOT used in typical pulsatile protocols |
| Synergy with GHRPs | 3–4× | greater GH pulse | CJC-1295 no-DAC + ipamorelin or GHRP-2 injected simultaneously produces approximately 3–4× greater GH pulse than either alone |
CJC-1295 is a synthetic GHRH analogue, but the term is often used loosely to refer to two fundamentally different compounds: the DAC form (with the Drug Affinity Complex modification) and the no-DAC form (also called Mod GRF 1-29). This distinction is not cosmetic — it determines the pharmacokinetics, GH secretion pattern, dosing protocol, and appropriateness for different use cases. Confusing the two forms is one of the most common errors in GH peptide protocols.
The Two Forms: A Critical Distinction
Native GHRH (Growth Hormone Releasing Hormone, 44 amino acids) has a plasma half-life of only 7 minutes due to enzymatic cleavage by dipeptidyl peptidase IV (DPP-IV). CJC-1295 was designed to solve this by substituting amino acids at key cleavage sites, producing a 29-amino acid GHRH fragment (the “Mod GRF 1-29” core) with approximately 30-minute half-life after subcutaneous injection.
The DAC modification adds a reactive maleimidyl group that covalently binds to albumin’s free cysteine residue (Cys34), creating a circulating reservoir with a 6–8 day half-life.
Form Comparison Table
| Form | Half-life | GH Pattern Produced | Typical Dose | Injection Frequency | Preferred For |
|---|---|---|---|---|---|
| CJC-1295 with DAC | 6–8 days | Sustained, non-pulsatile elevation (blunted pulsatility) | 1–2mg | Once or twice weekly | Maximizing IGF-1; less concern for pulsatility |
| CJC-1295 without DAC (Mod GRF 1-29) | ~30 min (subcut) | Clean pulsatile GH pulse when combined with GHRP | 100–200mcg | 2–3× daily, simultaneous with GHRP | Most performance and optimization protocols |
| Native GHRH 1-44 (reference) | ~7 min | Very brief GH pulse; not practical for protocols | N/A | Not typically used | Research reference only |
| Sermorelin (GHRH 1-29) | ~10–12 min (subcut) | Pulsatile; shorter duration than no-DAC CJC-1295 | 100–200mcg | 2–3× daily | Clinical GH deficiency (FDA-approved at one time) |
Human Evidence
Teichman et al. 2006 (PMID 16368745): CJC-1295 with DAC administered to healthy adults produced dose-dependent IGF-1 elevation of 1.5–3× above baseline, maintained for 14+ days after a single injection. This is the primary human pharmacokinetic study for the DAC form.
Ionescu & Frohman 2006 (PMID 16968793): Demonstrated that pulsatile GH secretion persists during continuous GHRH receptor stimulation — supporting the mechanistic rationale for pulsatile protocols using the no-DAC form.
Why Pulsatile GH Matters
Continuous GH elevation (as with the DAC form) shifts GH signaling away from pulsatile patterns associated with anabolic and lipolytic effects. Pulsatile GH preferentially:
- Drives hepatic IGF-1 production in discrete pulses
- Promotes lipolysis in adipose tissue
- Minimizes insulin resistance compared to continuous GH elevation
- Reduces risk of GH receptor desensitization over time
This is why the no-DAC form (Mod GRF 1-29) is the standard in performance protocols: it amplifies the body’s natural pulsatile GH rhythm rather than replacing it with continuous elevation.
Legal Status
| Jurisdiction | Status | Schedule | Notes |
|---|---|---|---|
| USA | Research chemical | Unscheduled | Not FDA-approved; WADA prohibited (S2) for competitive athletes |
| UK | Not scheduled | None | Legal to possess; WADA prohibited under UKAD anti-doping rules |
| Australia | Prescription restricted | Schedule 4 (TGA) | ASADA prohibited; not commercially available without prescription |
| Canada | Gray market | No schedule | No approved DIN; WADA prohibited for athletes |
| EU | Generally unscheduled | Varies by country | No EMA approval; WADA prohibited for athletes |
Related Pages
Sources
- Ionescu M, Frohman LA. Pulsatile secretion of growth hormone persists during continuous stimulation by CJC-1295. J Clin Endocrinol Metab. 2006;91(12):4792-7. PMID 16968793
- Teichman SL et al. Prolonged stimulation of GH and IGF-I secretion by CJC-1295. J Clin Endocrinol Metab. 2006;91(3):799-805. PMID 16368745
Frequently Asked Questions
What is the critical difference between CJC-1295 with DAC and without DAC?
The DAC (Drug Affinity Complex) modification causes CJC-1295 to bind covalently to circulating albumin, extending its half-life from ~30 minutes to 6–8 days. This creates sustained, non-pulsatile GH stimulation. The no-DAC form (Mod GRF 1-29) has a ~30-minute half-life and produces a clean GH pulse when injected. Most performance protocols use the no-DAC form specifically because pulsatile GH is more physiological and associated with better body composition outcomes.
Can CJC-1295 with DAC and GHRPs be combined?
Yes, but the combination produces a different GH pattern. CJC-1295 with DAC provides ongoing GHRH-receptor stimulation, while GHRPs continue to trigger pulsatile releases on top of the sustained baseline. Some practitioners use this approach for IGF-1 maximization, but it is less physiological than the no-DAC + GHRP combination. The Ionescu & Frohman 2006 study (PMID 16968793) confirmed that pulsatile GH secretion persists even during continuous GHRH stimulation.
Why is CJC-1295 without DAC (Mod GRF 1-29) preferred in most protocols?
Pulsatile GH secretion is the physiological norm, and pulsatile GH patterns are associated with superior anabolic signaling compared to continuous elevation. Injecting CJC-1295 no-DAC simultaneously with a GHRP produces a discrete, large GH pulse — mimicking (and amplifying) the body's natural pulsatile rhythm. The short 30-minute half-life means the system clears quickly, allowing normal GH regulation between doses and reducing the risk of receptor desensitization.