CJC-1295 With DAC vs Without DAC (and How Tesamorelin Compares)
“CJC-1295” is used for two different compounds, and mixing them up is one of the most common sources of confusion in growth-hormone research. Both are modified versions of GHRH. The difference is three letters, DAC, and it changes how long the compound stays active from about half an hour to about a week. Here is what that means for a study design.
At a glance
| CJC-1295 without DAC (Mod GRF 1-29) | CJC-1295 with DAC | Tesamorelin | |
|---|---|---|---|
| Based on | GHRH(1–29) with four amino-acid substitutions | The same modified GHRH(1–29), plus a reactive lysine linker | Full-length GHRH (44 amino acids) |
| Stabilizing feature | Substitutions that resist enzyme breakdown | Drug Affinity Complex binds circulating albumin | N-terminal trans-3-hexenoyl group |
| Approximate half-life in published reports | About 30 minutes | About 6–8 days | Short (tens of minutes) |
| Signal pattern | Short pulses, closer to natural GHRH release | Sustained, elevated baseline | Short pulses |
The shared starting point: GHRH(1–29)
Growth hormone-releasing hormone is 44 amino acids long, but its first 29 carry its activity at the GHRH receptor. Native GHRH(1–29) is broken down within minutes by the enzyme DPP-4 and other proteases. Both versions of CJC-1295 start from this fragment and replace four amino acids at the positions most vulnerable to breakdown. The result without anything added is often called Modified GRF (1–29), or Mod GRF 1-29.
What DAC adds
DAC stands for Drug Affinity Complex: a lysine residue carrying a reactive maleimide group added to the end of the peptide. After administration in research models, that group bonds to albumin, the most abundant protein in blood. Bound to albumin, the peptide is shielded from clearance, which is why its reported half-life stretches to roughly a week.
Why the difference matters
The body releases growth hormone in pulses. CJC-1295 without DAC produces short pulses that more closely resemble that natural pattern, which is why it is usually paired with a ghrelin-receptor agonist such as Ipamorelin, so that both pathways fire together. CJC-1295 with DAC instead raises baseline GHRH-receptor activity for days, which suits studies of sustained stimulation but blurs the pulsatile pattern.
Studying pulsatile GH release or GHRH + ghrelin synergy: CJC-1295 without DAC, often with Ipamorelin.
Studying sustained GHRH-receptor stimulation: CJC-1295 with DAC.
Using the full-length native sequence: Tesamorelin.
How Tesamorelin compares
Tesamorelin keeps all 44 amino acids of natural GHRH and adds a trans-3-hexenoyl group at the start to slow breakdown. It is the closest of the three to the native hormone and is used where researchers want full-length GHRH activity rather than the 1–29 fragment.
What we carry
Our CJC-1295 + Ipamorelin blend uses CJC-1295 without DAC in a 1:1 ratio with Ipamorelin, the standard pairing for pulsatile, dual-pathway research. We also carry Tesamorelin and Ipamorelin on their own. For background, see the CJC-1295 (no DAC) research profile and our comparison of GHRP-2, GHRP-6 and Ipamorelin.
Always check the label
Because the name covers two compounds, confirm which version a supplier is selling before you buy. The molecular weights differ, so a mass-spectrometry result on the Certificate of Analysis settles it. Every lot we sell is tested by Bioviridian Labs (ISO/IEC 17025, Texas) for HPLC purity, mass-spec identity, endotoxin and heavy metals. See the COA Library.
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For laboratory research use only. Not for human or veterinary use. This article summarizes published research for educational purposes and does not provide medical advice.