CJC-1295 DAC vs No DAC: One Name, Two Different Molecules

CJC-1295 with DAC and CJC-1295 "no DAC" are two different molecules that share a name. Both start from the same tetrasubstituted version of GRF(1-29), the active fragment of growth hormone-releasing hormone. The DAC form adds a reactive group that binds to albumin in the blood, which stretches its action from hours to days. The no-DAC form, also sold as Mod GRF(1-29), leaves that group off and is short-acting.

That one difference decides almost everything else, including which form any study actually used. Only the DAC form has published human data.

What "DAC" means

DAC stands for Drug Affinity Complex. In the paper that identified CJC-1295, the molecule is described as a tetrasubstituted form of human GRF(1-29) with an added maleimidopropionamide derivative of lysine at its C-terminus. That reactive group bonds to a free thiol on serum albumin after injection. In rats, CJC-1295 was still present in plasma beyond 72 hours, was found bound to albumin, and produced a fourfold larger growth hormone response over two hours than unmodified GRF(1-29) (Jetté 2005).

Our profile describes the four amino-acid substitutions as intended to resist enzymatic breakdown. The version sold as no DAC keeps those substitutions and drops the albumin-binding group, so it relies on the substitutions alone. See the CJC-1295 profile and the CJC-1295 no DAC profile.

What the human studies of the DAC form showed

• Ascending-dose trials in healthy adults. Two randomised, placebo-controlled, double-blind trials gave CJC-1295 under the skin as single ascending doses, or as two or three weekly or every-other-week doses. A single injection raised mean growth hormone 2- to 10-fold for six days or more and IGF-1 1.5- to 3-fold for 9 to 11 days; with repeated doses IGF-1 stayed above baseline for up to 28 days. No serious adverse reactions were reported, and the authors described it as relatively well tolerated, particularly at 30 or 60 µg/kg (Teichman 2006).

• Pulsatility study. In healthy men aged 20 to 40, a single injection of 60 or 90 µg/kg increased trough growth hormone 7.5-fold and mean growth hormone by 46%, while the frequency and size of growth hormone pulses were unchanged (Ionescu 2006). That answered a specific worry: continuous stimulation did not flatten the natural pulse pattern.

• The efficacy trial. A phase 2 trial in people with HIV-associated visceral obesity (NCT00267527, sponsor ConjuChem, 120 planned) was terminated and posted no results.

All published human doses were weight-based, in micrograms per kilogram. Fixed amounts quoted online are a different thing.

What is known about the no-DAC form

No human study of this specific molecule was found in PubMed, and no trial of it is registered on ClinicalTrials.gov (search, November 2026). The DAC studies above do not transfer to it, because the albumin binding is precisely what produced their multi-day effect.

The closest molecule with human data is its unmodified parent, GRF(1-29)-NH2, the compound behind sermorelin. In 30 healthy men, intravenous doses from 0.25 µg/kg caused significant growth hormone release, with the maximum at 1–2 µg/kg; the peptide was eliminated rapidly, and growth hormone stayed raised for about three hours (Wilton 1993). The no-DAC molecule differs from that parent by its four substitutions, so even this is an analogy, not evidence about it.

Why the confusion matters

• Studies get attached to the wrong product. The 2006 human studies used the DAC form, but they are routinely cited for no-DAC vials. A study of an albumin-bound, week-long molecule says little about a short-acting one.

• Timing differs by orders of magnitude. A half-life measured in days versus a parent compound cleared within hours means no interval or schedule carries over from one to the other.

• Combinations. The combination profiled here as CJC-1295 + ipamorelin uses the no-DAC form. See the CJC-1295 + ipamorelin profile and the CJC-1295 and ipamorelin dosage article.

• Read the label for the molecule, not the name. A vial labelled only "CJC-1295" does not say which form it contains; the certificate of analysis should state the molecular weight and sequence.

For a wider view of growth hormone-releasing analogues, the tesamorelin vs CJC-1295 comparison covers a GHRH analogue with a current FDA label (tesamorelin, sold as Egrifta), and the peptide half-life guide explains why half-life sets dosing intervals.

Frequently asked questions

Is Mod GRF 1-29 the same as CJC-1295?

It is the name commonly used for CJC-1295 without DAC. It is a different molecule from CJC-1295 with DAC, which carries the albumin-binding group.

What is the half-life of CJC-1295 with DAC?

5.8 to 8.1 days in the 2006 studies in healthy adults (Teichman 2006).

What is the half-life of CJC-1295 without DAC?

No published human study has measured it.

Which is better, CJC-1295 with or without DAC?

The evidence cannot say. They have never been compared in a study, and only the DAC form has been studied in people at all.