What CJC-1295 is and how it works
Growth hormone leaves the pituitary in pulses, triggered by growth-hormone-releasing hormone (GHRH) from the hypothalamus. Native GHRH runs to 44 amino acids, but nearly all of its activity sits in the first 29, the fragment CJC-1295 is built on. Four substitutions make it harder to break down. The important one puts D-alanine at position 2, blocking dipeptidyl peptidase-4, the enzyme that clips native GHRH apart within minutes.
The target is the GHRH receptor on the somatotroph cells of the anterior pituitary. Activation raises cyclic AMP, driving GH synthesis and release. Because the pathway runs through the pituitary, the brakes stay on: somatostatin and IGF-1 feedback both still apply. A GHRH analogue raises output only as far as the gland allows, unlike recombinant growth hormone itself.
What makes the compound last a week is not the peptide but what is bolted to its C-terminus. The drug affinity complex, shortened to DAC, is a maleimide group on a short spacer. After injection it bonds covalently to the one free thiol in circulating albumin, at cysteine-34, and the peptide then travels with the albumin pool, shielded from the kidney and from most peptidases. Two molecules therefore share one name. With the DAC it is the long-acting compound, sometimes written DAC:GRF; without it, the same sequence acts for minutes and is usually called Mod GRF 1-29.
What the research on CJC-1295 shows
The human evidence is a small body of phase 1 pharmacology. Teichman et al. (2006) gave healthy adults a single subcutaneous injection of the DAC version at 30, 60, 125 or 250 µg/kg. Mean growth hormone rose 2- to 10-fold and stayed above baseline for six days or more; IGF-1 rose 1.5- to 3-fold and stayed up for 9 to 11 days. Those are hormone read-outs in volunteers, not clinical outcomes: nobody measured body composition, wound healing or strength.
A continuous signal against a pulse
This matters because growth hormone physiology is built out of pulses. Secretion is episodic, largest after sleep onset and close to zero between bursts. Animal work shows tissues read the shape of that curve and not only the total amount: in rodents, liver gene expression follows the pulse profile rather than the mean concentration. A DAC compound raises the average and fills in the troughs. Mod GRF 1-29 adds one pulse and gets out of the way. No published trial has compared the two forms head to head.
After the early trials, development stopped: there is no phase 3 programme and no approval anywhere. Claims about longer-term use are borrowed from growth hormone physiology in general, or from the GHRH analogue that does hold a current approval, tesamorelin.
Doses of CJC-1295 used in published research
| Setting | Compound | Design | Read-out |
|---|---|---|---|
| Teichman et al. (2006), phase 1 | CJC-1295 with DAC | Single subcutaneous dose of 30, 60, 125 or 250 µg/kg, healthy adults | GH up 2- to 10-fold for ≥ 6 days; IGF-1 up 1.5- to 3-fold for 9–11 days |
| GHRH stimulation test, diagnostics | Plain GHRH(1-29), the older drug sermorelin | About 1 µg/kg intravenously, GH sampled over the next hour | Peak GH, as a measure of pituitary reserve |
| Mod GRF 1-29 | CJC-1295 without DAC | No dose-ranging trial published under this name | No controlled human data |
The record is thin. A single-dose study shows what one injection does to two hormones over ten days; it establishes neither a schedule nor a duration. These are study designs, not instructions, and no validated human dose exists.
Safety and side effects of CJC-1295
There is no long-term safety dataset; the list separates volunteer findings from the known class effects of the GH axis.
- Injection-site and vasomotor effects. The phase 1 single doses were described as well tolerated, with transient local reactions. Facial flushing after injection is a recognised class effect of GHRH analogues.
- Sustained IGF-1 elevation. One dose of the DAC version kept IGF-1 above baseline for more than a week. Approved therapies that raise IGF-1 are monitored by measuring it, the aim being to stay inside the age-adjusted reference range.
- Glucose handling. Growth hormone opposes insulin, so raising GH output can reduce insulin sensitivity. Tesamorelin, the licensed analogue in this class, carries a warning about glucose intolerance; CJC-1295 has no data of its own.
- Fluid retention and joint symptoms. Swelling, joint pain and carpal tunnel symptoms are documented in GH excess and GH replacement; CJC-1295 has never been given long enough in a trial to show them.
- What is in the vial. Two molecules share one name, and the material is usually sold blended with a second peptide. Mass spectrometry on the certificate is the only reliable way to tell the versions apart.
Regulatory status of CJC-1295 in Europe
CJC-1295 holds no marketing authorisation in the European Union or anywhere else, and because development was discontinued there is no EMA assessment and no licensed indication. In the EU a medicine needs an authorisation, granted centrally by the EMA or nationally; research peptides have none and are not sold for human use. Rules on possession and personal import are set member state by member state.
In sport the compound is prohibited. GHRH analogues are named in section S2 of the WADA Prohibited List, alongside growth hormone secretagogues and IGF-1 analogues, and S2 substances are banned at all times, in and out of competition. The wider comparison is in our guide to growth hormone secretagogues.
Sourcing and quality: CJC-1295 for research
King Peptides does not list CJC-1295 on its own. The only product containing it is the CJC-1295 + Ipamorelin Blend 5/5 mg, which pairs it with the ghrelin-receptor agonist ipamorelin. Because the name covers two molecules, read the product page and then the mass on the lot-specific certificate of analysis, which carries HPLC and mass spectrometry data. A measured mass near 3647 Da points to the DAC version, near 3368 Da to the version without it. For a blend the certificate should account for both peptides, and purity should be at least 99% by HPLC. A certificate is only worth reading if its lot number matches the vial in front of you; when the two disagree, the document describes a different batch.
Orders are dispatched from the Netherlands, inside the EU. Delivery usually takes 1–2 business days within the Netherlands and 3–5 business days elsewhere in the EU on the shop's own estimate, with no customs inside the union; shipments to the UK, Switzerland, Norway and other non-EU destinations can attract import rules and duties. Packaging is neutral and tracked, and buyers confirm at checkout that the order is for research and that they are 18 or older. Our guides to reading a certificate of analysis and to storage and reconstitution cover the chromatogram, the mass spectrum and why the powder belongs at −20 °C.
CJC-1295 frequently asked questions
Is CJC-1295 the same thing as Mod GRF 1-29? They share a sequence and a receptor. CJC-1295 with DAC binds albumin and acts for days; Mod GRF 1-29 lacks the linker and acts for minutes. Suppliers use both names loosely, so trust the certificate over the label.
Does the blend sold by King Peptides contain the DAC version? That is a question for the product page and the certificate, not for this page. The two forms differ by about 280 Da, which a mass spectrum resolves without difficulty.
Why is CJC-1295 so often studied with ipamorelin? The two act on different receptors in the same cell, and in human studies from the 1990s a GHRH and a GHRP together released considerably more growth hormone than either alone.
What does discontinued development mean in practice? No regulator has assessed the compound, no dose has been validated for repeated human use, and the published human record is essentially one phase 1 paper.
Research use only. CJC-1295 is described here for laboratory and scientific research. Research material carries no marketing authorisation, whatever the status of the molecule as a medicine elsewhere, and it is not intended for human or veterinary use. Nothing on this page is medical advice, and the dosing information above summarises published study designs. Always comply with the laws that apply in your country.