Source comparison
CJC-1295 vs Modified GRF(1-29): Critical Distinctions for Study Design
The terms 'CJC-1295' and 'modified GRF(1-29)' are not interchangeable, despite widespread supplier mislabeling. Modified GRF(1-29). Also called tetrasubstituted GRF(1-29) or Mod GRF. Is a GHRH analogue with four amino acid substitutions (Ala2, Gln8, Ala15, Leu
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- The terms 'CJC-1295' and 'modified GRF(1-29)' are not interchangeable, despite widespread supplier mislabeling. Modified GRF(1-29). Also called tetrasubstituted GRF(1-29) or Mod GRF. Is a GHRH analogue with four amino acid substitutions (Ala2, Gln8, Ala15, Leu27) that increase resistance to enzymatic degradation compared to native GHRH(1-29). Its half-life is approximately 30 minutes. Long enough to produce a measurable GH pulse but requiring administration 2–3 times daily to sustain effects. It does not contain DAC.
- CJC-1295, when properly specified, refers exclusively to the DAC-modified variant with the extended half-life profile. Research protocols using weekly dosing schedules require DAC-modified CJC-1295. Studies examining acute GH pulse dynamics or combination protocols with GHRP peptides (GHRP-2, GHRP-6, ipamorelin) often use modified GRF(1-29) instead because the short half-life allows precise temporal control over GH release timing.
- A 2006 dose-escalation study published in Growth Hormone & IGF Research administered CJC-1295 DAC at doses ranging from 30 to 120 mcg/kg as single subcutaneous injections and measured GH secretion patterns over 14 days. Mean GH AUC increased in a dose-dependent manner, with the 60 mcg/kg dose producing sustained GH elevations 2.6-fold above baseline without significant tachyphylaxis or receptor desensitization over the study period. Modified GRF(1-29) studies, by contrast, require repeat dosing every 4–8 hours to maintain comparable GH exposure.