Dac in CJC (CJC-1295)  stands for Drug Affinity Complex. It is actually a chemical augmentation of the CJC-1295 peptide, which increases its half-life in the body. Without DAC, CJC-1295 (also known as Modified GRF 1-29) has a very short half-life of about 30 minutes. 

With DAC, a “drug affinity complex” (modified GRF 1–29 without DAC, which is not bioavailable) has been added to CJC-1295 in order to extend its half-life. 

Hindered from binding by natural protective proteins that circulate in the wet area of the body, bound and introduced into the bloodstream, where it begins working and exhibits identical effects as if injected subcutaneously.

This enables it to remain in the body for 6–8 days[1] (or even longer, optionally depending on the specific study) and pulsatile sleep stimulates the pituitary gland in response with sustained releases of growth hormone (GH) and also stimulates release of insulin-like blast factor 1 (IGF-1).

Basically, DAC prevents CJC-1295 from being metabolized too fast, and the half-life is approximately 7 days, which means a slower release of GH/IGF-1. In simple terms, this formulation, developed by ConjuChem Biotechnologies, improves pharmacokinetics for potential use as a treatment of growth hormone deficiency or related problems.

A Look at CJC-1295 and Its Two Primary Variants

CJC-1295 is a synthetic analogue of growth hormone-releasing hormone (GHRH) (also known as growth hormone-releasing factor (GHRF)), which was developed in the early 2000s and is a first-generation GHRH remaining undeleted. GH has been shown to be important in optimising muscle mass, fat metabolism, recovery from exercise, bone density, and general well-being.

CJC-1295 NO DAC (Modified GRF 1-29): Short duration and works like the natural growth hormone release. Needs to be dosed frequently (many times a day) for any effect.

CJC-1295 with DAC: Long-acting through the use of DAC. Enables administration every few days (e.g., one or twice a week) via higher and sustained GH and IGF-1 levels.

The DAC is a maleimidopropionamide-lysine (MPA-Lys) unit attached to the C-terminus of the peptide. This allows reversible but high-affinity binding to serum albumin, prolonging circulation and improving overall bioavailability.

How DAC Works: The Mechanism

1. Albumin binding:

After injection, the DAC moiety forms a covalent bond with free thiol groups on albumin, thereby protecting the peptide from enzymatic degradation (e.g., by dipeptidyl peptidase-4 or DPP-4).

2. Longer Half-Life

Renal filtration and clearance are reduced by the binding of albumin, thus keeping the peptide in the bloodstream for a longer period of time.  

3. Sustained GH Stimulation:

Extended presence ensures more consistent stimulation of GHRH receptors on pituitary somatotroph cells than bolus administration, thereby increasing basal levels of GH and also the duration that IGF-1 remains elevated (frequently 0.5- to 3-fold increased for days to weeks following treatment).

Studies have consistently shown that CJC-1295 with DAC increases plasma GH  by  2-10 fold and IGF-1 levels by 0.5 -3-fold for a duration of 6 days or longer in humans, while preserving some natural pulsatility.

Potential Benefits and Considerations

Extended action from DAC  might help factors like better recovery, body composition, energy, and all other ‘anti-aging’ effects in a research environment. However, continuous GH elevation differs from the patterns of natural pulsatile GH, which some prefer for mimicking physiology.

Disclaimer

CJC 1295 (with or without DAC) has not been approved for human use by the FDA or any international equivalent; it is a research chemical and is recommended for investigational purposes only. It has been researched in a clinical trial context, but was subjected to regulatory focus (e.g., FDA compounding discussions).

 Do see a doctor first – self-medication will involve shuttling hormones back and forth, possibly causing side-effects such as water retention, altered insulin sensitivity, or interference with your natural GH secretion levels.

Conclusion 

In conclusion, the DAC is the critical innovation that turns CJC-1295 from a short-acting peptide into a long-acting growth hormone secretagogue. By binding to albumin and prolonging its half-life from minutes to days, the DAC makes it more convenient to dose and maintain elevated levels of GH/IGF-1, which is attractive for research studies on muscle repair, fat loss, recovery, and aging.

However, this long-acting effect also translates to reduced pulsatile secretion of natural GH, which may not be ideal for all individuals. Most importantly, CJC-1295 with DAC is still an investigational compound and not an approved drug for general use. It should only be within a research environment.