CJC-1295 is a synthetic peptide designed to mimic a natural hormone in your brain that triggers the release of growth hormone. It works by binding to the same receptors as your body’s own growth hormone-releasing hormone (GHRH), but it stays active in the bloodstream far longer than the natural version. CJC-1295 is not approved by the FDA and is not a component of any FDA-approved drug, but it has been studied in clinical trials and is widely discussed in anti-aging and performance contexts.
How CJC-1295 Works
Your pituitary gland, a pea-sized structure at the base of your brain, contains specialized cells called somatotropes that produce growth hormone. Normally, a signaling molecule called GHRH travels from the hypothalamus to the pituitary, locks onto receptors on those cells, and tells them to synthesize and release growth hormone into the bloodstream. CJC-1295 is a lab-made analog of GHRH that activates those same receptors.
The key difference is durability. Natural GHRH breaks down in the blood within minutes. CJC-1295 has been chemically modified to resist that breakdown, which means a single dose can keep stimulating growth hormone production for days rather than moments. In clinical testing on healthy adults aged 21 to 61, subcutaneous injections of CJC-1295 produced sustained, dose-dependent increases in both growth hormone and IGF-1 (a downstream hormone that mediates many of growth hormone’s effects on tissues). Notably, one study in healthy young men found that these increases occurred without disrupting the natural pulsatile rhythm of growth hormone secretion, meaning the body still released growth hormone in its normal wave-like pattern rather than in a flat, constant stream.
Two Versions: With DAC and Without DAC
CJC-1295 comes in two distinct forms, and the difference between them matters significantly.
CJC-1295 with DAC includes a “drug affinity complex,” a chemical addition that allows the peptide to bind to a protein in the blood called albumin. This binding protects it from being cleared by the kidneys and gives it a half-life of roughly 6 to 8 days. That means growth hormone levels stay elevated for an extended period after a single injection. The trade-off is that this sustained elevation doesn’t closely resemble the body’s natural growth hormone pattern, which rises and falls throughout the day.
CJC-1295 without DAC (often marketed as Mod GRF 1-29) has a much shorter half-life of about 30 minutes. Because it clears quickly, it produces a sharp pulse of growth hormone that more closely mimics what the pituitary does on its own. People who prioritize a natural secretion pattern typically prefer this version, though it requires more frequent dosing.
Effects on Growth Hormone and Body Composition
The primary documented effect of CJC-1295 is raising circulating levels of growth hormone and IGF-1. Growth hormone plays a role in maintaining lean body mass, regulating fat metabolism, supporting bone density, and influencing sleep quality and recovery. IGF-1 acts as growth hormone’s main downstream messenger, carrying out many of these tissue-level effects.
Animal research provides some of the clearest body composition data. In mice genetically engineered to produce no GHRH at all (and therefore very little growth hormone), once-daily CJC-1295 treatment restored normal growth, maintained normal lean mass, and normalized subcutaneous fat levels. Human clinical data on body composition changes is more limited. The existing trials in healthy adults focused primarily on confirming that CJC-1295 reliably raises growth hormone and IGF-1, and on safety, rather than measuring long-term changes in muscle or fat.
Why It Is Often Paired With Ipamorelin
CJC-1295 is frequently combined with a peptide called ipamorelin, and the rationale comes down to how each one stimulates growth hormone through a different pathway. CJC-1295 acts on the GHRH receptor. Ipamorelin acts on a separate receptor called the ghrelin receptor (the same one activated by the “hunger hormone”). When both pathways are activated simultaneously, the result is a stronger growth hormone pulse than either peptide produces alone.
This two-signal approach more closely resembles what happens naturally, since your body uses both GHRH and ghrelin-like signals to regulate growth hormone output. The combination allows for a robust pulsatile release without relying heavily on a single mechanism, which in theory reduces the chance of receptor desensitization over time.
Side Effects in Clinical Studies
In the clinical trials conducted on healthy adults, no serious adverse reactions were reported. The peptide was described as “safe and relatively well tolerated,” particularly at lower doses of 30 or 60 micrograms per kilogram of body weight. The most commonly noted side effects in peptide therapy settings include redness or irritation at the injection site, temporary flushing, and mild headaches. Higher doses tended to produce more noticeable side effects, though none reached the threshold of serious in the published trial data.
It’s worth noting that these trials were relatively short, lasting 28 to 49 days, so long-term safety data in humans is essentially nonexistent. Sustained elevation of growth hormone and IGF-1 over months or years carries theoretical risks, including insulin resistance, joint pain, fluid retention, and potential effects on cell growth that haven’t been fully studied in the context of CJC-1295 specifically.
Regulatory and Legal Status
CJC-1295 occupies a gray area. The FDA evaluated multiple forms of the substance (free base, acetate, with and without DAC) and declined to add any of them to the list of approved bulk drug substances that compounding pharmacies can use. None are components of any FDA-approved medication. This means CJC-1295 cannot legally be compounded and prescribed as a standard pharmaceutical in the United States under current regulations.
For athletes, the picture is even more clear-cut. The World Anti-Doping Agency lists CJC-1295 as prohibited at all times, both in and out of competition, under its broader ban on growth hormone and growth hormone secretagogues. Any athlete subject to WADA testing who uses CJC-1295 faces a doping violation regardless of the context.
How It Is Typically Administered
CJC-1295 is injected subcutaneously, usually into the abdomen or thigh. Dosing protocols differ depending on the version. The DAC version, with its multi-day half-life, is typically injected once per week at doses around 600 micrograms. The non-DAC version, because it clears so quickly, is generally administered on five out of seven days, often before bedtime to align with the body’s natural nighttime growth hormone surge. When combined with ipamorelin, the non-DAC version follows the same schedule.
In clinical research, doses of 30 to 90 micrograms per kilogram of body weight were tested. The lower doses (30 to 60 micrograms per kilogram) showed effective growth hormone elevation with fewer side effects than higher doses. Growth hormone pulsatility was specifically assessed in one study using blood samples drawn every 20 minutes over a 12-hour overnight period, confirming that the natural secretion rhythm was preserved at these doses.