KPV

So What Does This Actually Mean?

Plain English summary — no PhD required

CJC-1295 is a synthetic version of a hormone your hypothalamus naturally produces called GHRH (growth hormone-releasing hormone). Your hypothalamus sends GHRH to your pituitary gland as a signal to release growth hormone. CJC-1295 is essentially a longer-lasting, more stable version of that signal.

What It Does

When CJC-1295 reaches the pituitary gland, it triggers the release of growth hormone (GH) in the same pulsatile pattern your body naturally uses. That GH then travels to the liver and other tissues, where it stimulates production of IGF-1 — the compound that actually carries out most of GH's effects on muscle, bone, and fat metabolism. In a published clinical study, CJC-1295 produced a 2–10 fold increase in GH levels and a 1.5–3 fold increase in IGF-1, with effects lasting up to 28 days.

Why It Matters

The key distinction between CJC-1295 and simply injecting growth hormone directly is that CJC-1295 works through your body's own regulatory system. It stimulates your pituitary to release GH naturally, which preserves the pulsatile pattern and feedback loops that keep the system in balance. This is why it's studied as a more physiologically harmonious approach to GH axis research than direct GH administration.

The Bottom Line

CJC-1295 is one of the most clinically studied GHRH analogs, with published human pharmacokinetic data. The DAC (Drug Affinity Complex) version binds to albumin in the blood, extending its half-life from 30 minutes to nearly a week. It is a research-only compound classified as prohibited by WADA.

Overview

What is CJC-1295?

CJC-1295 (also referenced as CJC1295, cjc-1295 peptide, or Modified GRF 1-29) is a synthetic analog of growth hormone-releasing hormone (GHRH), the endogenous hypothalamic peptide that stimulates the anterior pituitary gland to secrete growth hormone (GH). Developed by ConjuChem Biotechnologies, CJC-1295 is a tetrasubstituted 30-amino-acid peptide based on the first 29 amino acids of native GHRH, with four amino acid substitutions that confer significantly enhanced metabolic stability and receptor binding affinity.

The compound is available in two primary forms: CJC-1295 without DAC (Modified GRF 1-29), which has a half-life of approximately 30 minutes and produces pulsatile GH release; and CJC-1295 with DAC (Drug Affinity Complex), which covalently binds to serum albumin to extend the half-life to 5.8–8.1 days.

Key Takeaways

• CJC-1295 is a synthetic GHRH analog — a stabilized, longer-acting version of the hypothalamic signal that tells the pituitary to release growth hormone

• The DAC (Drug Affinity Complex) modification allows CJC-1295 to bind to albumin in blood, extending its half-life from ~30 minutes to 6–8 days vs. ~30 min for CJC-1295 without DAC

• Published human PK data: produced 2–10× GH increase and 1.5–3× IGF-1 increase lasting up to 28 days (Teichman et al., JCEM 2006)

• Preserves pulsatile GH release pattern (unlike direct GH administration), maintaining the hypothalamic-pituitary feedback axis

• WADA-prohibited research compound; commonly studied in combination with Ipamorelin for synergistic GH axis stimulation

Composition

Molecular Composition

Amino Acid Sequence

Tyr-Ala-Asp-Ala-Ile-Phe-Thr-Asn-Ser-Tyr-Arg-Lys-Val-Leu-Ala-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Met-Ser-Arg (30 AA)

CJC-1295 is a 30-amino-acid peptide derived from the first 29 residues of human GHRH, with four strategic amino acid substitutions: Ala² → D-Ala (protects against dipeptidyl peptidase IV cleavage), Gln⁸ → Ala (reduces asparagine deamidation), Ala¹⁵ → Ala (stability enhancement), and Leu²⁷ → Met (receptor binding optimization). These substitutions collectively extend the peptide's biological half-life and enhance its affinity for the GHRH receptor (GHRHR) on pituitary somatotroph cells.

Mechanism of Action

How Does It Work?

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CJC-1295 extends growth hormone release by mimicking GHRH and binding to albumin, producing sustained GH pulses over days rather than minutes.

CJC-1295 acts as a functional agonist at the GHRH receptor (GHRHR), a G-protein coupled receptor expressed on the surface of pituitary somatotroph cells. Upon binding, CJC-1295 activates adenylyl cyclase via the Gαs protein, increasing intracellular cyclic AMP (cAMP) concentrations. Elevated cAMP activates protein kinase A (PKA), which phosphorylates downstream targets that ultimately trigger the synthesis and secretion of growth hormone from somatotroph secretory granules.

The secreted growth hormone then acts on the liver and peripheral tissues to stimulate the production of insulin-like growth factor-1 (IGF-1), the primary mediator of GH's anabolic and tissue-repair effects. In a landmark clinical study (Teichman et al., 2006), CJC-1295 administration produced a 2–10 fold increase in mean GH concentrations and a 1.5–3 fold increase in IGF-1 levels, with effects persisting for up to 28 days.

CJC-1295 Mechanism of Action — Simplified signaling pathway diagram. For research reference only.

"After multiple CJC-1295 doses, mean IGF-I levels remained above baseline for up to 28 days. The estimated half-life of CJC-1295 was 5.8–8.1 days — a duration unprecedented for a synthetic GHRH analog." — Teichman et al., Journal of Clinical Endocrinology & Metabolism, 2006

Signaling Pathways

Key Research Pathways

GHRHR / cAMP / PKA Signaling

Binds GHRH receptor on pituitary somatotrophs, activating adenylyl cyclase → cAMP → PKA cascade that triggers GH synthesis and secretion.

GH / IGF-1 Axis Activation

Secreted GH stimulates hepatic and peripheral IGF-1 production, the primary mediator of anabolic, tissue-repair, and metabolic effects.

Pulsatile GH Release Preservation

Maintains physiological pulsatility of GH secretion, preventing receptor downregulation and preserving long-term somatotroph responsiveness.

Albumin Binding (DAC form)

The Drug Affinity Complex (DAC) modification enables reversible covalent binding to serum albumin, dramatically extending circulating half-life.

Research Highlights

Key Findings from the Literature

• 2–10 fold increase in mean GH concentrations in healthy adult subjects (Teichman et al., 2006)

• 1.5–3 fold increase in IGF-1 levels persisting up to 28 days after multiple doses

• Preserves physiological pulsatility of GH secretion (Ionescu & Frohman, 2006)

• Estimated half-life of 5.8–8.1 days (DAC form) vs. ~30 min (without DAC)

• Normalizes growth in GHRH-knockout mouse models (Alba et al., 2006)

• Four amino acid substitutions confer resistance to DPP-IV and other proteases