Modified GRF (1-29) · Growth Hormone Releasing Hormone Analogue
A synthetic analogue of growth hormone releasing hormone (GHRH) that stimulates pulsatile GH secretion from the pituitary gland. Used in research contexts for body composition, recovery and anti-aging applications.
CJC-1295 is a synthetic analogue of growth hormone releasing hormone (GHRH), modified to improve stability and extend half-life. It exists in two forms: CJC-1295 without DAC (Drug Affinity Complex), also called Modified GRF 1-29, which has a short half-life of approximately 30 minutes mimicking a natural pulse; and CJC-1295 with DAC which has an extended half-life of 6–8 days providing continuous stimulation.
Most research protocols use the without-DAC version to preserve the natural pulsatile pattern of GH release, which is considered more physiologically appropriate.
CJC-1295 binds to GHRH receptors on pituitary somatotroph cells, stimulating the synthesis and release of growth hormone. Unlike exogenous HGH which provides a flat, sustained elevation, CJC-1295 amplifies the natural pulsatile GH release pattern — the pituitary responds to the signal and releases GH in a pulse, then returns to baseline. This preserves the natural feedback mechanisms of the GH axis.
Published research in healthy adults demonstrated that CJC-1295 produced dose-dependent increases in GH levels of 2–10 fold above baseline, with corresponding increases in IGF-1 of 1.5–3 fold. Effects on body composition including increased lean mass and reduced fat mass have been documented in longer-term studies.
When combined with a GHRP like Ipamorelin, the synergistic effect on GH release is significantly greater than either compound alone — CJC-1295 amplifies the amplitude of the pulse while Ipamorelin triggers the pulse timing.
These two compounds work through completely different receptor pathways and are complementary rather than redundant. CJC-1295 acts on GHRH receptors; Ipamorelin acts on ghrelin/GHS receptors. Together they produce a more complete and pronounced GH pulse than either alone — which is why they are typically used in combination.
As with all compounds that raise IGF-1, individuals with active cancer or pre-cancerous conditions should exercise caution. The effect on blood glucose should be monitored in diabetic individuals. Insulin blunts the GH response significantly — fasting 2–3 hours before administration is recommended in research protocols.