Skip to content
The Peptide Effect
preclinicalGrowth Hormone

CJC-1295

Also known as: Modified GRF 1-29, Mod GRF 1-29, CJC-1295 without DAC, CJC-1295 no DAC, Tetrasubstituted GRF(1-29)

CJC-1295 (without DAC) is a modified synthetic analog of growth hormone-releasing hormone (GHRH) with four amino acid substitutions that resist enzymatic degradation. It extends the biological half-life of GRF 1-29 while maintaining a pulsatile GH release profile, making it one of the most popular peptides for growth hormone optimization. It is frequently paired with GH secretagogues like ipamorelin for synergistic effects.

Key Facts

Mechanism
CJC-1295 binds to the GHRH receptor on pituitary somatotroph cells, stimulating growth hormone synthesis and release. The four amino acid substitutions at positions 2, 8, 15, and 27 (Ala→D-Ala, Gly→Ala, Leu→Ala, Met→Leu respectively) confer resistance to dipeptidyl peptidase IV (DPP-IV) cleavage, significantly extending its active half-life compared to native GHRH or unmodified sermorelin. Unlike the DAC (Drug Affinity Complex) version, CJC-1295 without DAC maintains a more physiological pulsatile GH release pattern rather than sustained GH elevation.
Research Status
preclinical
Half-Life
~30 minutes (without DAC)
Molecular Formula
C₁₅₂H₂₅₂N₄₄O₄₂
Primary Use
Growth Hormone
Table of Contents

Benefits

  • Sustained growth hormone elevation with improved half-life over native GHRHstrong
  • Synergistic GH release when combined with GHRP peptides (e.g., ipamorelin)moderate
  • Improved body composition — reduced fat mass and increased lean massmoderate
  • Enhanced post-exercise recovery and tissue repairmoderate
  • Maintains pulsatile GH release pattern (without DAC version), preserving natural physiologymoderate

Dosage Protocols

RouteDosage RangeFrequencyNotes
Subcutaneous injection100 mcg1–3× dailyMost common protocol; typically dosed pre-bed, pre-workout, or upon waking on an empty stomach
Subcutaneous injection100 mcg CJC-1295 + 100 mcg ipamorelin2–3× dailyCombination protocol for synergistic GH release; one of the most popular peptide stacks
Subcutaneous injection300 mcg (saturation dose)Once daily at bedtimeHigher single-dose protocol sometimes used; fasting for 1–2 hours before and after injection recommended

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

  • Facial flushing and warmth shortly after injectioncommon
  • Headachecommon
  • Water retention and mild bloatingcommon
  • Numbness or tingling in extremitiesrare
  • Transient hypotension or lightheadednessrare

Explore next

Articles

Frequently Asked Questions

What is the difference between CJC-1295 with DAC and without DAC?
CJC-1295 without DAC (also called Modified GRF 1-29) has a half-life of approximately 30 minutes and produces pulsatile GH release similar to natural physiology. CJC-1295 with DAC (Drug Affinity Complex) binds to serum albumin, extending its half-life to 6–8 days and producing a sustained, constant elevation of GH — sometimes called "GH bleed." The without-DAC version is generally preferred because pulsatile release is considered more physiological and may carry fewer side effects from chronically elevated GH/IGF-1.
Why is CJC-1295 commonly paired with ipamorelin?
CJC-1295 (a GHRH analog) and ipamorelin (a GHRP/ghrelin mimetic) work through different receptors and complementary mechanisms. GHRH analogs amplify the GH pulse, while GHRPs initiate the pulse. When combined, they produce a synergistic GH release significantly greater than either peptide alone. Ipamorelin is preferred over other GHRPs in this stack because it does not significantly increase cortisol, prolactin, or appetite.
When should I inject CJC-1295 for best results?
CJC-1295 is best injected on an empty stomach (fasting 1–2 hours before and 30–60 minutes after). The most popular timing is at bedtime to amplify the natural nocturnal GH pulse. A second dose upon waking (before breakfast) or 30 minutes pre-workout is also common. Avoid injecting within 2 hours of eating, as elevated blood sugar and insulin blunt GH release.
What is GH bleed and why is it a concern?
GH bleed refers to a continuous, non-pulsatile elevation of growth hormone levels — typically associated with CJC-1295 with DAC. The concern is that the body naturally releases GH in pulses, and chronic elevation may lead to desensitization of GH receptors, increased side effects (water retention, insulin resistance), and potentially mimic some risks of exogenous HGH use. The without-DAC version avoids this issue by maintaining pulsatile release.
How long should I run a CJC-1295 cycle?
Typical protocols run 8–12 weeks followed by a 4-week break, though some anti-aging clinics prescribe it continuously for extended periods. There is no universally agreed-upon cycling protocol, as clinical trial data for long-term use in healthy adults is limited. Periodic blood work monitoring IGF-1 and fasting glucose levels is recommended regardless of cycle duration. This is not medical advice — consult a physician.

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
    A synthetic GH secretagogue (MK-677) and a GHRH analog (CJC-1295) act synergistically to promote GH release in humans(2008)PubMed ↗
  3. 3
    Growth hormone-releasing hormone analogs: chemistry and pharmacology(1999)PubMed ↗
  4. 4
    Dipeptidyl peptidase IV resistant analogues of growth hormone-releasing hormone(2005)PubMed ↗

Last updated: 2026-02-14