CJC-1295 (also known as Modified GRF 1-29) and CJC-1295 DAC are both Growth Hormone Releasing Hormones (GHRH). Their action in the human body is identical with the difference being the half-life of each peptide. Modified GRF 1-29 has a very short acting half-life of about 30 minutes, while CJC-1295 DAC has a half-life of about 8 days, making it suitable for injecting just 1 time per week.
(All info gathered via internet )