CJC-1295 with DAC vs CJC-1295 without DAC: Key Differences Explained

If you’ve been researching growth hormone secretagogues, you’ve almost certainly run into a confusing naming situation: CJC-1295 with DAC and CJC-1295 without DAC. They sound nearly identical, but they behave very differently in the body. Understanding the distinction is essential for anyone studying GHRH analogs in a research context.

What Is CJC-1295?

CJC-1295 is a synthetic analog of growth hormone-releasing hormone (GHRH). It was engineered to stimulate the pituitary gland to release growth hormone (GH) by mimicking the body’s natural GHRH signal. The base peptide is a modified version of the first 29 amino acids of GHRH — often called Mod GRF 1-29 or CJC-1295 without DAC.

The DAC Modification: What It Does

DAC stands for Drug Affinity Complex. It’s a chemical modification added to the C-terminus of the peptide that allows it to covalently bind to serum albumin — the most abundant protein in blood plasma. This bond dramatically extends the peptide’s half-life.

Without DAC, CJC-1295 (Mod GRF 1-29) has a half-life of roughly 30 minutes — similar to native GHRH. With DAC, the half-life extends to 6–8 days, turning a short-acting peptide into a sustained-release compound.

CJC-1295 Without DAC (Mod GRF 1-29)

Also marketed as Modified GRF 1-29 or simply “Mod GRF,” this is the shorter-acting version. Key research characteristics:

• Half-life: ~30 minutes
• GH release pattern: Pulse-based — mimics natural GH pulsatility
• Onset: Rapid (peaks within 15–30 min)
• Typical pairing: Often combined with GHRP peptides (GHRP-2, GHRP-6, Ipamorelin) for synergistic GH release

Researchers studying pulsatile GH secretion prefer Mod GRF 1-29 because it preserves the natural rhythm of GH release. It creates sharp peaks followed by normal troughs — consistent with the body’s physiological pattern.

CJC-1295 With DAC

The DAC-modified version maintains a near-constant blood level of the peptide over days. This produces what researchers call a “GH bleed” — a sustained, low-level elevation of GH rather than sharp pulses.

• Half-life: 6–8 days
• GH release pattern: Sustained baseline elevation
• Dosing frequency: Once or twice weekly in research protocols
• IGF-1 impact: Studies show significant IGF-1 increases over 28-day periods

A 2006 clinical study published in the Journal of Clinical Endocrinology & Metabolism found that CJC-1295 with DAC produced dose-dependent increases in GH and IGF-1 that persisted for up to 14 days after a single injection in healthy adults.

Head-to-Head Comparison

Why the Naming Confusion Exists

The confusion is understandable. CJC-1295 originally referred only to the DAC version. Over time, vendors began marketing Mod GRF 1-29 under the CJC-1295 name with a “without DAC” qualifier, which muddied the terminology. Always verify which compound you’re looking at when reading research protocols.

Research Combinations

CJC-1295 without DAC is frequently combined with Ipamorelin in research settings. Ipamorelin is a GHRP that amplifies GH release through a different receptor pathway (ghrelin receptor). The two together produce a synergistic GH pulse significantly larger than either alone.

View CJC-1295/Ipamorelin Blend →

Research Citations

Written by the NorthPeptide Research Team