CJC-1295 (also called Modified GRF 1-29) is a synthetic analog of the body's own growth hormone-releasing hormone, used to stimulate pulsatile growth hormone secretion for goals like body recomposition, recovery, and anti-aging.
What it does
Your hypothalamus naturally releases GHRH (growth hormone-releasing hormone) in short bursts, which tells the pituitary gland to fire pulses of growth hormone (GH). Native GHRH breaks down within about two minutes due to an enzyme called DPP-IV (dipeptidyl peptidase-IV). CJC-1295 is engineered with four amino acid substitutions — at positions 2, 8, 15, and 27 — that block DPP-IV from degrading it, stretching its half-life to roughly 30 minutes Siham 2021. That's long enough to trigger a meaningful GH pulse, but short enough to preserve the natural on-off rhythm of GH secretion.
Once it reaches the pituitary, CJC-1295 binds GHRH receptors on somatotroph cells (the cells responsible for making and releasing GH). This activates adenylyl cyclase, raises intracellular cAMP, and kicks off a signaling cascade through PKA (protein kinase A) that both transcribes new GH and triggers release of stored GH vesicles. The resulting GH pulse then travels to the liver, where it drives IGF-1 (insulin-like growth factor 1) production. IGF-1 in turn activates the PI3K/AKT/mTOR pathway — the master switch for protein synthesis, satellite cell activation (muscle repair), fat breakdown, and collagen production.
Because CJC-1295 works inside the body's existing feedback loop, somatostatin (the natural 'off' signal for GH) still applies the brakes, which is why it doesn't suppress the hypothalamic-pituitary axis the way exogenous synthetic HGH does. This also explains why it's frequently paired with ipamorelin, a ghrelin-receptor agonist that suppresses somatostatin through an entirely different receptor system — the two mechanisms are additive, and co-administration has been shown to produce two to four times the GH per pulse compared with either agent alone Jørgensen 1999.
What the evidence shows
HIV-associated visceral adiposity and body composition Limited human trial data — one registered clinical trial, small sample
A registered clinical trial (NCT00267527) evaluated CJC-1295 in HIV-positive patients with visceral obesity — excess fat around internal organs, a known complication of antiretroviral therapy. The rationale was that GH axis dysregulation is common in this population and that restoring pulsatile GH might shift fat distribution. Results from this trial inform much of the human tolerability and IGF-1 response data cited for this compound, including documented IGF-1 elevations of 1.5–3x above baseline. This is a narrow population, and extrapolating findings to healthy adults requires caution.
Detection and pharmacokinetics (sports doping context) Strong analytical chemistry data; indirect pharmacokinetic insight
Several peer-reviewed studies have characterized CJC-1295's pharmacokinetics and metabolite profile in the context of anti-doping detection Siham 2021Gilles 2022Ebru 2026Laura 2020Mark 2019. While these studies weren't designed to measure therapeutic outcomes, they confirm the compound's presence in biological fluids post-administration and provide real-world data on half-life, urinary excretion windows, and structural stability — all consistent with the ~30-minute half-life model. The equine plasma detection work Mark 2019 also validates that the compound is active at low concentrations in vivo.
How it's used
In studies and self-reported protocols, doses range from 100 mcg to 200 mcg per injection, administered subcutaneously (injected under the skin, typically in the abdomen). Frequency ranges from once daily to three times daily. The most common approach is a single bedtime injection, timed to coincide with the body's largest natural GH pulse during early sleep. When dosed multiple times per day, injections are typically spaced at least 30 minutes away from meals, since elevated insulin blunts GH release. CJC-1295 without DAC (the version covered here) has a half-life of roughly 30 minutes and should not be confused with CJC-1295 with DAC, which has a half-life of 6–8 days and produces continuous rather than pulsatile GH elevation — a pharmacologically different profile.
Side effects and safety
Mild side effects reported in studies and self-reports include transient flushing, injection site irritation, and mild water retention. Moderate effects include headache, peripheral numbness or tingling, and joint discomfort — patterns consistent with GH excess seen with other GH-stimulating agents. The most serious theoretical concern is accelerating the growth of pre-existing GH-responsive tumors; this is not a documented outcome specific to CJC-1295, but it is a class-level risk for all GH secretagogues. Absolute contraindications include active malignancy, pregnancy, breastfeeding, and critical illness. People with diabetes should monitor blood glucose closely, as GH elevation can increase insulin resistance. Long-term safety data in healthy humans simply does not exist — the compound lacks the decades of clinical use that would establish a proper risk profile.
Bottom line
CJC-1295 without DAC has a well-understood mechanism and a pharmacokinetic profile that makes physiologic sense — it amplifies natural GH pulsatility rather than overriding it. However, the human clinical evidence base is thin: one small registered trial in an HIV population and a body of analytical detection studies NCT00267527Siham 2021Gilles 2022Mark 2019. Anyone drawn to it for body composition or recovery should weigh a credible mechanism against genuinely sparse human outcome data and the absence of long-term safety studies.