INFORMATION / PUBLIC-RECORD CLARIFICATION
CJC-1295 DAC vs No-DAC (Modified GRF 1-29): The Half-Life Difference
These are pharmacokinetically different molecules that marketing routinely treats as one. The DAC variant lasts days; the no-DAC form lasts minutes to hours. Here is the distinction, drawn straight.
The distinction the literature keeps untangling
The single most-conflated point in this compound's record is CJC-1295 DAC vs no DAC. They share the same backbone — the tetrasubstituted hGRF(1-29) sequence with four protease-resistant substitutions [2] — but they differ in one decisive feature: whether the molecule carries the albumin-binding handle. That one difference changes the half-life from minutes to days, and it changes how every dose, every duration claim, and every safety statement should be read.
Marketing and forums routinely sell or describe "CJC-1295" without specifying which form, which makes most loose claims about the compound ambiguous. A duration claim that is true for the DAC form is false for the no-DAC form, and vice versa. This page keeps the two apart on purpose.
What Is CJC-1295 DAC?
DAC stands for Drug Affinity Complex — the albumin-conjugation chemistry that makes CJC-1295 long-acting. The DAC variant carries a maleimidopropionyl-lysine handle that undergoes a covalent reaction with the free thiol on circulating serum albumin, forming a peptide-albumin conjugate that extends the plasma half-life toward that of albumin itself [2]. The effective circulating species is therefore the much larger peptide-albumin complex.
In rats, the albumin conjugate produced roughly 4-fold higher growth-hormone area-under-the-curve than unconjugated hGRF(1-29) and remained detectable in plasma beyond 72 hours [2]. That is the design that makes CJC-1295 long-acting — and it is the form the term "CJC-1295" most precisely refers to in the original literature.
What is CJC-1295 DAC?
"DAC" = Drug Affinity Complex, the albumin-conjugation chemistry. In rats the conjugate gave about 4-fold higher GH AUC than unconjugated hGRF(1-29) and was detectable in plasma beyond 72 hours [2] — the design that makes CJC-1295 long-acting.
What is CJC-1295 with DAC?
The version carrying a maleimidopropionyl-lysine handle that covalently bonds to a thiol on circulating serum albumin, forming a peptide-albumin conjugate that extends the plasma half-life toward that of albumin [2] — hence a multi-day duration of action.
Modified GRF (1-29): The No-DAC Form
Modified GRF (1-29) is the no-DAC form. It keeps the same four substitutions that block dipeptidylpeptidase-IV cleavage, but it lacks the albumin-binding moiety [2]. Without the covalent tether to albumin, it clears at roughly the rate of native GHRH(1-29) — short-acting, in the minutes-to-hours range — and so it produces a brief GH pulse rather than the days-long elevation of the DAC form.
That makes Modified GRF 1-29 pharmacokinetically closer to a short-acting GHRH pulse than to the long-acting CJC-1295 DAC, despite the shared name lineage. When a source says "CJC-1295" and means the short-acting no-DAC peptide, every duration and dosing inference changes. The two are not interchangeable, and conflating them is the error this dossier exists to flag.
How Long Does CJC-1295 Stay in the Body?
For the DAC form, the CJC-1295 half life is the core pharmacokinetic fact: 5.8 to 8.1 days in healthy adults [1]. A single dose elevates GH for six days or more, and after multiple doses IGF-1 remains above baseline for up to 28 days [1]. The no-DAC Modified GRF 1-29 form is short-acting — minutes to hours — reflecting native GHRH(1-29) clearance with the protease-resistant substitutions [2].
That multi-day exposure window of the DAC form is also why duration matters to the safety reading: the longer IGF-1 stays elevated, the more the sustained-IGF-1 concern applies [8]. A short pulse and a multi-day elevation are not the same exposure, even from the same backbone molecule.
How long does CJC-1295 stay in the body?
The DAC form's estimated half-life is 5.8 to 8.1 days in healthy adults, with IGF-1 elevated up to 28 days after multiple doses [1]. The no-DAC Modified GRF 1-29 form is short-acting — minutes to hours [2]. Which form is meant determines the answer.
How much CJC-1295 DAC should I take?
The DAC variant's multi-day half-life (5.8-8.1 days) was studied at 30-90 ug/kg single subcutaneous doses [1][3]; murine work showed once-daily 2 ug normalized growth [4]. Online fixed-microgram protocols are not derived from controlled human trials.