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The Peptide Effect
preclinicalGrowth Hormone

CJC-1295 DAC

Also known as: CJC-1295 with DAC, CJC-1295 with Drug Affinity Complex, DAC:GRF, ConjuChem CJC-1295

CJC-1295 DAC is a modified growth hormone-releasing hormone (GHRH) analog identical to CJC-1295 (Mod GRF 1-29) but with the addition of a Drug Affinity Complex (DAC) — a reactive chemical group that covalently binds to serum albumin after injection. This albumin binding extends the half-life from approximately 30 minutes to roughly 8 days, enabling sustained growth hormone elevation from a single weekly injection. Originally developed by ConjuChem Biotechnologies for clinical use, CJC-1295 DAC remains one of the most potent GHRH analogs available in the research peptide market.

Key Facts

Mechanism
CJC-1295 DAC shares the same base peptide sequence as CJC-1295 (Mod GRF 1-29) — a 29-amino-acid GHRH analog with four substitutions for DPP-IV resistance. The key differentiator is the Drug Affinity Complex: a maleimidopropionic acid (MPA) linker attached via a lysine residue that reacts with Cys34 of serum albumin after subcutaneous injection. This covalent albumin binding creates a circulating peptide-albumin conjugate with a dramatically extended half-life (~8 days vs ~30 minutes). The result is sustained, continuous stimulation of GHRH receptors on pituitary somatotrophs, producing a steady elevation of GH and IGF-1 rather than the pulsatile peaks seen with the non-DAC version. This continuous GH elevation is often referred to as "GH bleed."
Research Status
preclinical
Half-Life
~8 days (due to albumin binding via DAC)
Molecular Formula
C₁₆₅H₂₇₁N₄₇O₄₆
Primary Use
Growth Hormone
Table of Contents

Benefits

  • Sustained GH and IGF-1 elevation for days from a single injection — demonstrated 2–10× increase in GH AUC in clinical studiesstrong
  • Convenience — only requires 1–2 injections per week compared to 1–3 daily injections for non-DAC versionstrong
  • Significant and sustained increase in serum IGF-1 levels lasting 6–14 days post-injectionstrong
  • Improved body composition — reduced fat mass and increased lean body mass in both clinical and anecdotal settingsmoderate
  • Enhanced recovery from exercise and injury through sustained GH elevationmoderate

Dosage Protocols

RouteDosage RangeFrequencyNotes
Subcutaneous injection2 mgOnce weeklyMost common protocol. Single weekly injection provides sustained GH elevation for approximately 6–8 days due to DAC-mediated albumin binding.
Subcutaneous injection1 mgTwice weekly (e.g., Monday/Thursday)Split-dose protocol preferred by some users to reduce peak-related side effects while maintaining steady GH levels throughout the week.
Subcutaneous injection2 mgOnce every 5 daysSlightly more aggressive dosing schedule. Some users prefer this timing to maintain consistently elevated IGF-1 without any trough period.

Medical disclaimer

Dosage information is provided for educational reference only. Always follow your prescriber's instructions and consult a qualified healthcare provider before starting any peptide protocol.

Side Effects

  • GH "bleed" — non-pulsatile, continuous GH elevation may disrupt natural GH secretion rhythm and receptor sensitivitycommon
  • Water retention and bloating — frequently reported due to sustained GH elevationcommon
  • Numbness and tingling in extremities (paresthesia) — common with elevated GH/IGF-1common
  • Flushing and warmth at injection site and facial area shortly after administrationcommon
  • Potential insulin resistance — chronic GH elevation can impair glucose metabolism and increase fasting blood sugarrare
  • Headache — reported in some users, especially during initial weeks of userare

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Frequently Asked Questions

What is the difference between CJC-1295 DAC and CJC-1295 without DAC (Mod GRF 1-29)?
The base peptide is identical — both are 29-amino-acid GHRH analogs with four amino acid substitutions for DPP-IV resistance. The critical difference is the Drug Affinity Complex (DAC), a chemical linker that covalently binds to serum albumin after injection. Without DAC, the half-life is approximately 30 minutes, producing sharp, pulsatile GH peaks similar to natural physiology. With DAC, the half-life extends to approximately 8 days, producing continuous, sustained GH elevation (GH bleed). Many practitioners prefer the non-DAC version because pulsatile GH release is considered more physiological, but the DAC version offers the convenience of weekly injections.
What is GH bleed and is it problematic?
GH bleed refers to the continuous, non-pulsatile elevation of growth hormone caused by the extended half-life of CJC-1295 DAC. Naturally, the body releases GH in distinct pulses — the largest occurring during deep sleep. CJC-1295 DAC overrides this pattern by continuously stimulating GHRH receptors. The concerns with GH bleed include: (1) potential desensitization of GH receptors over time, (2) increased side effects from chronically elevated GH (water retention, insulin resistance, carpal tunnel-like symptoms), and (3) mimicking some risks associated with exogenous HGH administration. Whether GH bleed is truly problematic long-term remains debated, but it is the primary reason many users prefer the non-DAC version.
Can CJC-1295 DAC be combined with a GHRP like ipamorelin?
It can be, but it is less commonly stacked than the non-DAC version. The rationale for combining GHRH analogs with GHRPs is synergy — GHRH amplifies the GH pulse while GHRPs initiate it. However, since CJC-1295 DAC already provides continuous GH stimulation rather than pulsatile release, the synergistic benefit is somewhat reduced. Some users still combine them, typically injecting ipamorelin at bedtime to amplify the nocturnal GH pulse on top of the baseline elevation from CJC-1295 DAC. If pulsatile release and GHRP stacking are priorities, the non-DAC version is generally preferred.
Why did ConjuChem stop developing CJC-1295 DAC clinically?
ConjuChem Biotechnologies conducted Phase I and Phase II clinical trials with CJC-1295 DAC in the mid-2000s. The trials demonstrated robust and sustained GH and IGF-1 elevation. However, a participant death during a clinical trial (though the FDA later stated it was unrelated to the compound) caused significant complications for the program. ConjuChem eventually went through financial difficulties and the clinical development stalled. The compound was never submitted for FDA approval, and it remains available only through research chemical suppliers.
Is there a desensitization concern with CJC-1295 DAC?
This is a debated topic. The concern is that continuous GHRH receptor stimulation (unlike natural pulsatile stimulation) could lead to receptor downregulation over time, reducing the GH response. Published clinical data from ConjuChem showed sustained GH and IGF-1 elevation over multiple weekly doses without obvious desensitization in short-term studies. However, long-term data (beyond several months) is lacking. Some users cycle CJC-1295 DAC (8–12 weeks on, 4 weeks off) as a precaution, though there is no definitive evidence establishing whether cycling is necessary.

References

  1. 1
    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(2006)PubMed ↗
  2. 2
    Effects of a chemical conjugate of growth hormone-releasing hormone with albumin on body composition in HIV-positive patients(2004)PubMed ↗
  3. 3
    Long-acting growth hormone releasing factor analogs: pharmacokinetics and pharmacodynamics of CJC-1295(2007)PubMed ↗
  4. 4
    Growth hormone-releasing hormone analogs: chemistry and pharmacology(1999)PubMed ↗

Last updated: 2026-02-14