This article is for educational and research purposes only. Nothing here constitutes medical advice. Consult a licensed healthcare provider before using any peptide.
What Is CJC-1295?
CJC-1295 is a synthetic analog of growth hormone-releasing hormone (GHRH), specifically a modified version of the first 29 amino acids of GHRH (known as GRF 1-29 or sermorelin). Developed by ConjuChem Biotechnologies, CJC-1295 was engineered with four amino acid substitutions at positions 2, 8, 15, and 27 that protect it from enzymatic degradation by dipeptidyl peptidase-IV (DPP-IV), dramatically extending its biological activity compared to native GHRH.
The peptide exists in two forms: CJC-1295 with DAC (Drug Affinity Complex) and CJC-1295 without DAC (often called Modified GRF 1-29 or Mod GRF). The DAC variant includes a reactive lysine residue that covalently binds to circulating albumin after injection, extending the half-life from approximately 30 minutes to 6-8 days.
Mechanism of Action
Both forms of CJC-1295 work by binding to the GHRH receptor (GHRH-R) on anterior pituitary somatotroph cells:
- GHRH receptor activation: Stimulates cAMP-dependent signaling pathways that trigger GH synthesis and secretion from pituitary somatotrophs.
- Amplification of natural pulses: Unlike direct GH injection, CJC-1295 amplifies existing GH pulses rather than creating artificial spikes, working in concert with the body's somatostatin rhythm.
- IGF-1 elevation: Sustained GH elevation leads to increased hepatic IGF-1 production, mediating many of the downstream anabolic and metabolic effects.
DAC vs. No DAC: The Critical Difference
The presence or absence of the Drug Affinity Complex fundamentally changes the peptide's pharmacokinetics and use case:
CJC-1295 with DAC binds to albumin and creates a sustained, continuous elevation of GH over days. A single injection can elevate GH and IGF-1 levels for 6-8 days. Research by Teichman et al. (2006) showed that a single 60 mcg/kg dose produced sustained GH elevation for up to 6 days and IGF-1 elevation for 9-11 days. This is convenient for dosing (once or twice per week) but creates a non-physiological, continuous GH elevation pattern — sometimes called a "GH bleed" — rather than the natural pulsatile rhythm.
CJC-1295 without DAC (Mod GRF 1-29) has a half-life of approximately 30 minutes, creating acute GH pulses that more closely mimic natural physiology. This requires more frequent dosing (2-3 times daily) but preserves the pulsatile GH secretion pattern that the body's tissues respond to optimally. Most peptide researchers prefer this form when combined with a GHRP like ipamorelin.
Dosing Protocols
- CJC-1295 with DAC: Typically dosed at 1-2 mg once or twice per week via subcutaneous injection
- CJC-1295 no DAC (Mod GRF): 100-200 mcg per injection, 2-3 times daily, usually combined with 200-300 mcg ipamorelin or another GHRP at the same time
- Timing: Best on an empty stomach; the pre-bed dose is considered the most important as it amplifies the natural nocturnal GH surge
Side Effects
Reported side effects include injection site reactions (redness, swelling), flushing and warmth after injection, water retention, increased hunger, and mild tingling or numbness in extremities. The DAC variant may produce more pronounced water retention due to sustained GH elevation. Both forms are generally considered well-tolerated in research settings.
The Bottom Line
CJC-1295 is one of the most well-characterized GHRH analogs in peptide research. The choice between DAC and no-DAC variants comes down to convenience versus physiological mimicry. Most experienced researchers prefer the no-DAC form paired with a GHRP for synergistic, pulsatile GH release that better approximates the body's natural rhythm. Neither form is FDA-approved for anti-aging or performance applications.