CJC-1295 turns up constantly in biohacking forums, clinic marketing and anti-doping bulletins. Far less often quoted is the human study that started the conversation. Published in 2006 in The Journal of Clinical Endocrinology and Metabolism, the trial by Teichman and colleagues is the foundational dataset for this long-acting growth hormone-releasing hormone (GHRH) analog. It is worth reading for what it shows and for what it never set out to show.
The Problem CJC-1295 Was Built to Solve
Natural GHRH tells the pituitary to release growth hormone (GH), which in turn prompts the liver and other tissues to produce insulin-like growth factor I (IGF-I). The hormone works, but it is short-lived. As the study's authors note, the therapeutic use of GHRH to boost GH secretion has been limited by its brief duration of action. A molecule that clears within minutes is hard to turn into a practical treatment.
CJC-1295 was designed as a long-acting GHRH analog. The trial asked three questions: how does the body handle the drug (pharmacokinetics), what does it do to GH and IGF-I (pharmacodynamics), and is it safe in healthy adults?
How the Trial Was Designed
The work consisted of two randomized, double-blind, placebo-controlled, ascending-dose trials lasting 28 and 49 days, run at two investigational sites. Participants were healthy adults aged 21 to 61.
- Study one: Participants received CJC-1295 or placebo as a single subcutaneous injection at one of four ascending dose levels.
- Study two: Participants received two or three doses of CJC-1295 or placebo, given weekly or biweekly.
The main outcomes were peak concentrations and area under the curve for GH and IGF-I, along with standard pharmacokinetic parameters for the drug itself.
What the Numbers Showed
The results are striking for a single injection:
- Growth hormone: Mean plasma GH concentrations rose 2- to 10-fold in a dose-dependent manner, and the elevation lasted 6 days or more.
- IGF-I: Mean plasma IGF-I rose 1.5- to 3-fold, staying elevated for 9 to 11 days.
- Half-life: The estimated half-life of CJC-1295 was 5.8 to 8.1 days. Most injectable peptides are cleared in minutes to hours, so this is exceptionally long.
- Repeated dosing: After multiple doses, mean IGF-I levels stayed above baseline for up to 28 days. The authors describe evidence of a cumulative effect.
- Safety: No serious adverse reactions were reported. The drug was described as safe and relatively well tolerated, particularly at doses of 30 or 60 µg/kg.
The dose-dependence is useful. It suggests the hormonal response tracks with the amount of drug given, which is what you would expect from a real pharmacological effect rather than noise.
DAC vs. "Mod GRF 1-29": Clearing Up a Common Confusion
Much of the confusion around CJC-1295 comes from two different products sharing one name.
The molecule in this trial is the long-acting version. It is commonly described as CJC-1295 "with DAC," where DAC stands for drug affinity complex. That chemical modification is what lets the peptide persist for days, and it is the reason a half-life of nearly a week was observed.
The other product is usually sold as "CJC-1295 without DAC." Strictly speaking, that is a different peptide, more accurately called modified GRF (1-29), or "mod GRF 1-29." It is a modified fragment of GHRH without the long-acting component and is expected to act far more briefly. The trial described here did not test it. Data from this study cannot be carried over to mod GRF 1-29, and the reverse is also true. If someone cites "the CJC-1295 study" to support a short-acting product, they are mixing up two molecules.
What This Study Does Not Tell Us
This is the part that gets lost in online discussion. The trial was a pharmacokinetic, pharmacodynamic and safety study in healthy volunteers. The outcomes were hormone levels and drug behavior. The abstract reports no measurements of:
- muscle mass or strength
- fat loss or body composition
- athletic or physical performance
- sleep, recovery, bone density or cognitive function
- long-term safety
Raising GH and IGF-I is a biomarker result. It is not the same as demonstrating a clinical benefit. Whether higher IGF-I translates into meaningful improvements in healthy adults is a separate question that this trial did not answer. The trial was also short, with durations of 28 and 49 days, so it says little about what happens with months or years of exposure. Sustained elevation of IGF-I is something researchers watch carefully, because the GH/IGF-I axis is deeply tied to growth, metabolism and aging biology. The abstract does not address those long-term questions, and neither should readers assume they were settled.
Regulatory Reality
CJC-1295 has never been approved as a medicine. The authors concluded that the data support its potential utility as a therapeutic agent, but potential is not approval. Today it exists as a research peptide, and products sold under the name vary in quality, identity and labeling. It is also prohibited in sport: the World Anti-Doping Agency bans it as a growth hormone-releasing factor, so competitive athletes risk sanctions.
The Bottom Line
The 2006 trial is a solid early-phase study. It shows that a single subcutaneous dose of a long-acting GHRH analog can lift GH for roughly a week and IGF-I for more than a week, that repeated dosing builds on that effect, and that short-term tolerability in healthy adults looked good. It is also a narrow study: no body composition, no performance endpoints, no long-term follow-up, and no data on the shorter-acting mod GRF 1-29 that is so often sold under the same label. Anyone weighing claims about CJC-1295 should treat this paper as evidence of hormonal activity and short-term safety, not as proof of the benefits that marketing often implies.
