CJC-1295: A Multi-Day Switch for the Growth-Hormone Axis

The short version

CJC-1295 is a synthetic analog of growth-hormone-releasing hormone (GHRH), built on the first 29 amino acids of the natural hormone with four substitutions that make it resistant to breakdown. In its "DAC" form, it also chemically bonds to a protein in the blood (serum albumin), stretching its effect from minutes to days. It is not approved by the FDA or any regulator for human use anywhere — it is sold strictly as a research chemical.

Unlike some research peptides, CJC-1295 does have real early-phase human pharmacology behind it: single doses in healthy adults produced sustained, dose-dependent increases in growth hormone and IGF-1 lasting a week or more ^[11], and the growth-hormone axis's normal pulsatile secretion pattern was preserved rather than flattened ^[12]. That is genuine human data. What is missing is any large, long-term safety or efficacy trial — the original commercial development program was discontinued, and this page will not gloss over that.

What it is

CJC-1295 is built on human GHRH(1-29), the first 29 residues of the natural growth-hormone-releasing hormone, with four amino-acid substitutions (D-Ala at position 2, Gln at 8, Ala at 15, Leu at 27) that stabilize its alpha-helix shape and block breakdown by the enzyme DPP-4 as well as deamidation and oxidation. The "DAC" (Drug Affinity Complex) variant adds a chemical linker at the C-terminus that reacts with a free thiol on circulating albumin, forming a covalent peptide-albumin bond — this is what stretches its half-life toward that of albumin itself, on the order of days rather than minutes. The "no-DAC" form, often called Modified GRF(1-29), keeps the four stabilizing substitutions but skips the albumin-binding chemistry, so it acts for minutes to hours instead.

How it works

CJC-1295 binds the growth-hormone-releasing hormone receptor (GHRHR) on somatotroph cells in the anterior pituitary, activating Gs-protein/cAMP/PKA signaling that stimulates both synthesis and pulsatile release of growth hormone. Growth hormone released into circulation then drives the liver to produce IGF-1, the hormone responsible for most of GH's downstream tissue effects. Because the DAC form stays bound to albumin for days, a single dose keeps this GHRH-receptor stimulation running continuously rather than in a single brief pulse — the key design difference from the body's own GHRH, which is released and cleared within minutes. Notably, human studies found that even under this sustained stimulation, the pituitary kept releasing GH in its normal pulsatile rhythm rather than a flat, continuous stream ^[12] — an important distinction from simply infusing growth hormone directly.

What the research shows

Pharmacology review. A 2025 Nature Reviews Endocrinology paper synthesizes GHRH-analog pharmacology broadly, including the receptor signaling and design rationale behind long-acting analogs like CJC-1295 ^[8].

Confirmed identity in a black-market product. In 2010, analytical chemists used high-resolution LC-MS/MS to identify CJC-1295 as the actual active ingredient in an unlabeled "GHRH" product seized in an anti-doping investigation — direct proof the compound circulates outside any regulated supply chain ^[9].

Human pharmacokinetics. In 11 healthy young men, CJC-1295 shifted several serum proteins, and one of those shifts (an immunoglobulin/albumin-fragment signal) correlated linearly with IGF-1 levels — a candidate biomarker of GH-axis activation ^[10]. In a separate study of healthy adults aged 21-61, single subcutaneous doses of 30 or 60 micrograms/kg produced 2- to 10-fold increases in mean plasma GH lasting six or more days, and 1.5- to 3-fold increases in IGF-1 lasting 9-11 days; after repeated dosing, IGF-1 stayed above baseline for up to 28 days, with an estimated half-life of 5.8-8.1 days ^[11].

Preserved pulsatility. In healthy men aged 20-40, a single 60 or 90 microgram/kg dose raised basal GH roughly 7.5-fold and mean GH and IGF-1 by about 45-46% a week later, while the normal frequency and size of GH pulses stayed unchanged ^[12] — evidence that CJC-1295 amplifies the existing rhythm rather than overriding it.

Reported effects, cautions & safety

People using CJC-1295 in research-use communities report a fairly consistent cluster of effects — anecdotal, not clinical evidence, drawn from peptide-user forums, bodybuilding boards, and clinic write-ups, not controlled studies. Deeper, more restful sleep is the single most commonly described effect, often noticed within the first week, which fits the biology since growth hormone release peaks during deep sleep. Faster training recovery, gradual fat loss (especially around the midsection over several weeks), a leaner look with better muscle retention, and occasionally more daytime energy or mental clarity round out the reported benefits. On the downside, water retention and bloating are very commonly described — reportedly worse with the long-acting DAC form than the short-acting no-DAC form — along with tingling or numbness in the hands, injection-site reactions, occasional flushing, fatigue, headache, and, less often, increased hunger (usually attributed to a co-administered compound rather than CJC-1295 itself) and higher blood sugar.

The cited cautions are more consequential. CJC-1295 has never been approved for human use anywhere, and published human evidence is limited to a handful of early pharmacology studies — no large or long-term trial has shown it is safe or effective ^[11]. A pharmacology review of the broader GHRH-analog class notes design considerations, including immunogenicity, relevant to long-acting, albumin-binding molecules like this one ^[8]. Growth hormone itself causes the kidneys to retain sodium and water, which is the likely mechanism behind the commonly reported bloating and hand tingling, and sustained GH-axis stimulation can reduce insulin sensitivity — a real concern for anyone with diabetes or prediabetes. The original long-acting CJC-1295 DAC development program was discontinued, and a patient death during that era is frequently cited alongside the halted trial, though a causal link to the compound was never established in the public record. CJC-1295 is also prohibited in sport at all times by the World Anti-Doping Agency.

Where it fits in Research Peptide Fundamentals

CJC-1295 anchors the growth-hormone-axis branch of this map. Where BPC-157 works through a vascular-repair mechanism still being characterized mostly in rodents, CJC-1295 has genuine, repeated human pharmacology data behind it — a rare thing among unapproved research peptides ^[11][12]. It sits well short of tirzepatide or PT-141, the two compounds on this desk with FDA approval and large trial programs, but it is meaningfully further along than MOTS-c, which has no interventional human data at all. See the comparison page for how all five stack up.