CJC-1295 (no DAC) / Modified GRF (1-29): Structure, Research and Specifications
CJC-1295 without DAC, also known as Modified GRF (1-29) or tetrasubstituted GRF (1-29), is a synthetic analogue of the first 29 amino acids of growth-hormone-releasing hormone (GHRH). Four amino-acid substitutions make it more resistant to enzymatic breakdown than the native fragment. This page explains how it differs from sermorelin and from CJC-1295 with DAC, summarises the published research and gives the specifications of the material we supply.
For in vitro research use only. Not for human or animal use. Nothing on this page is medical advice.
What is CJC-1295 (no DAC)?
Native GHRH is a 44-amino-acid hormone, but its first 29 amino acids, GRF (1-29), are enough to activate the GHRH receptor. That fragment is known as sermorelin. Its main limitation is a very short half-life, only a few minutes, because the enzyme dipeptidyl peptidase-4 (DPP-4) and other enzymes cleave it quickly.
Modified GRF (1-29) keeps the 29-amino-acid backbone but replaces four amino acids, at positions 2, 8, 15 and 27, to make it more resistant to this breakdown. The result is a GHRH analogue with a longer half-life than sermorelin, reported as around 30 minutes, while still producing a short, pulse-like stimulus at the pituitary.
The name “CJC-1295 no DAC” is widely used for this peptide because it has the same four substitutions as CJC-1295, but without the drug affinity complex (DAC) that binds albumin.
Sermorelin vs Mod GRF (1-29) vs CJC-1295 with DAC
| Sermorelin | Mod GRF (1-29) / no DAC | CJC-1295 with DAC | |
|---|---|---|---|
| Backbone | GRF (1-29) | GRF (1-29) | GRF (1-29) |
| Substitutions | None | D-Ala2, Gln8, Ala15, Leu27 | D-Ala2, Gln8, Ala15, Leu27 |
| Albumin binding (DAC) | No | No | Yes, via a maleimide-modified lysine |
| Reported half-life | A few minutes | Around 30 minutes | About 6–8 days in humans |
| Stimulus profile | Short pulse | Short pulse | Prolonged elevation |
Chemical data
| Name | CJC-1295 without DAC (Modified GRF 1-29, tetrasubstituted GRF 1-29) |
|---|---|
| Sequence | Tyr-D-Ala-Asp-Ala-Ile-Phe-Thr-Gln-Ser-Tyr-Arg-Lys-Val-Leu-Ala-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Leu-Ser-Arg-NH2 |
| Length | 29 amino acids |
| Molecular formula | C152H252N44O42 |
| Molecular weight | ≈ 3367.9 g/mol |
| Appearance | White lyophilised powder |
| Available sizes | CJC-1295 no DAC 10mg |
Mechanism of action
- GHRH receptor agonism. Mod GRF (1-29) binds GHRH receptors on pituitary somatotroph cells and stimulates synthesis and release of endogenous growth hormone.
- Enzyme resistance. The D-Ala2 substitution protects against DPP-4 cleavage at the N-terminus. The other substitutions improve stability and reduce oxidation (Met27 → Leu).
- Pulsatile release. Without albumin binding, it gives a short stimulus, so GH release stays pulse-like and subject to normal feedback by somatostatin and IGF-1.
- Pairing with ghrelin agonists. GHRH analogues and ghrelin-receptor agonists such as ipamorelin act on different receptors, which is why they are often studied together.
What the published research shows
GRF (1-29) analogues
The four substitutions in Modified GRF (1-29) come from structure–activity research on GRF (1-29) analogues. That work aimed to improve resistance to enzymatic degradation while keeping full activity at the GHRH receptor.
CJC-1295 with DAC in humans
The closely related CJC-1295 with DAC was studied in healthy adults (Teichman et al., 2006, Journal of Clinical Endocrinology & Metabolism). A single administration raised plasma GH 2- to 10-fold for 6 days or more and IGF-1 levels for 9 to 11 days. Because the no-DAC form lacks albumin binding, these prolonged effects do not apply to it.
Research use today
Mod GRF (1-29) is used in laboratory research as a short-acting, enzyme-resistant GHRH-receptor agonist, often alongside ghrelin-receptor agonists to study how the two pathways interact.
Limitations of the evidence
- Published clinical data relate mainly to CJC-1295 with DAC, not to the no-DAC form.
- Clinical development of CJC-1295 was stopped during phase 2 after the death of a trial participant. The death was considered unrelated to treatment, but the programme was halted as a precaution.
- There are no long-term human safety data for Mod GRF (1-29).
Regulatory status
CJC-1295, with or without DAC, is not a licensed medicine in the UK and has not been approved by the MHRA, FDA or EMA. GHRH and its analogues are prohibited in sport under the WADA Prohibited List (S2). Sterling Research supplies CJC-1295 (no DAC) only as a research reagent for in vitro laboratory use. It must not be used in humans or animals.
Storage and handling in the lab
- Store lyophilised powder at −20 °C, sealed and protected from light and moisture.
- Let the vial reach room temperature before opening to limit condensation.
- Prepare solutions to your laboratory’s validated protocols, with appropriate PPE and aseptic technique.
- Avoid repeated freeze–thaw cycles of solutions. Aliquot where your protocol allows.
Quality
Every batch of CJC-1295 (no DAC) we supply is independently tested by Janoshik for purity and identity before it is released for sale.
Related research compounds
Frequently asked questions
Is CJC-1295 no DAC the same as Mod GRF (1-29)?
Yes. “CJC-1295 without DAC”, “Modified GRF (1-29)” and “tetrasubstituted GRF (1-29)” are different names for the same 29-amino-acid peptide with four substitutions.
What does DAC mean?
DAC stands for drug affinity complex. In CJC-1295 with DAC, a modified lysine at the end of the peptide binds to albumin in the blood, extending its half-life from minutes to days.
How is it different from sermorelin?
Sermorelin is unmodified GRF (1-29). Mod GRF (1-29) has four amino-acid substitutions that make it more resistant to enzymatic breakdown, giving it a longer half-life.
Why is it often studied with ipamorelin?
Mod GRF (1-29) acts on the GHRH receptor and ipamorelin acts on the ghrelin receptor. Studying them together lets researchers examine how the two pathways interact in regulating growth hormone release.
Is CJC-1295 approved as a medicine?
No. Clinical development was halted during phase 2, and it is not approved by the MHRA, FDA or EMA.
References
- Teichman SL, et al. Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults. J Clin Endocrinol Metab. 2006;91(3):799–805. doi:10.1210/jc.2005-1536
- Modified GRF (1-29). Sequence, substitutions and half-life
- CJC-1295. Development history and DAC technology
This page is for scientific information only. Sterling Research Group Ltd supplies CJC-1295 (no DAC) strictly for in vitro laboratory research. Not for human or animal use, and not for diagnostic or therapeutic purposes.