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Experimental/Growth Hormone SecretagoguesResearch peptide

CJC-1295 (no DAC)

aka Mod GRF 1-29

A modified GHRH analog that amplifies natural growth-hormone pulses without sustained suprapulse elevation.

Educational explainer of a research peptide. Profiles in this section deliberately omit clinical-trial citations, dosing protocols, and purchase links. Not FDA-approved as a supplement; not a recommendation to use.

Overview

CJC-1295 without DAC (also called Mod GRF 1-29) is a short-acting GHRH analog with a half-life of about 30 minutes, designed to enhance pulsatile GH release.

Source
  • Synthesized in research laboratories
Forms
  • Subcutaneous injection

Mechanism of action

Binds the GHRH receptor on the pituitary to stimulate growth-hormone synthesis and release; works synergistically with ghrelin-receptor peptides like ipamorelin.

Pathways
  • · GHRH-R → cAMP → GH transcription and release
Receptors
  • · Growth hormone-releasing hormone receptor (GHRH-R)
Hormones
  • · Growth hormone
  • · IGF-1

How it acts on the body

Mod GRF 1-29 reproduces the bioactive portion of native GHRH (the first 29 amino acids) with four substitutions that protect it from rapid enzymatic breakdown. Unlike the long-acting DAC variant, it does not stay elevated for days — it acts like a stronger, slightly longer GHRH signal lasting roughly 30 minutes.

Combined with a GHRP (which acts on a separate receptor), it produces a synergistic 'two-key' GH release: GHRH widens the pituitary release gate while the GHRP supplies the trigger. The result is a GH pulse several times larger than either alone, but because the signal still ends in under an hour, the pituitary's negative-feedback system (somatostatin) remains intact and downregulation is minimized.

Hormonal & endocrine impact

How this peptide is reported to shift specific hormones and signaling molecules. Directionality reflects research literature and preclinical models, not clinical prescribing data.

Projected hormonal trajectory
Illustrative curves derived from reported direction of effect. Not measured patient data.

Curves are schematic shapes (sigmoid for increases/decreases, damped oscillation for modulation/stabilization) anchored to a 100% baseline. They communicate direction and tempo of change reported in research literature — not absolute hormone concentrations.

Growth hormoneIncreases
Boosts pulse amplitude when natural GH release is initiated.
IGF-1Increases
Liver IGF-1 rises with sustained use; degree depends on baseline.
SomatostatinModulates
Negative feedback remains functional because the GHRH signal is brief.
Cortisol & prolactinStabilizes
Unaffected when CJC is used without a non-selective GHRP.
Insulin sensitivityDecreases
Long-term GH/IGF-1 elevation can mildly impair glucose control.

Effects on the body

Increases
GH pulse amplitude
Supports
Body composition and recovery

Organ system effects

Skeletal Muscle

Better recovery and lean-tissue support reported.

Endocrine

Stimulates the pituitary directly without altering ghrelin signaling.

Reported effects

Drawn from preclinical research, anecdote, and small-scale clinical observation. No evidence grades are assigned — most peptides on this page lack rigorous human trials.

  • Amplifies natural GH pulses without prolonged elevations
  • Often stacked with GHRPs for full somatotropic effect
  • May improve sleep, recovery, and skin quality

Potential side effects

Common
  • · Facial flushing
  • · Injection-site reaction
  • · Tingling
Rare
  • · Headache
  • · Mild nausea
Serious
  • · Unknown long-term effects on IGF-1 and insulin sensitivity

Drug interactions

Glucocorticoids
May suppress GH response.
moderate

Pairing context

Often combined with
  • Ipamorelin
    Classic GHRH + GHRP research combination for synergistic pulses.
Avoid combining with
  • Active malignancy
    GH/IGF-1 stimulation is generally avoided.
Important. Research peptides described here are not FDA-approved supplements. Supplement Scholar does not endorse, recommend, or link to any source for purchase. Consult a qualified clinician before considering any peptide therapy.