CJC-1295: A Long-Acting Signal, Studied Only By Injection

The short version

CJC-1295 is a synthetic analog of growth-hormone-releasing hormone (GHRH), the signal the hypothalamus sends to the pituitary to trigger growth-hormone release. It comes in two forms that are easy to confuse: "CJC-1295 DAC," which is chemically bound to blood albumin and lasts for days, and "no-DAC" (also called Modified GRF 1-29), which lasts only minutes to hours. Every published human pharmacology study on this compound used subcutaneous injection — there is no published human data for an oral, sublingual, or transdermal form of either variant ^[9][10].

CJC-1295 is not approved for human use anywhere. It's sold as a research chemical, and in 2024 FDA briefing materials specifically flagged immunogenicity concerns when reviewing it for a pharmacy-compounding bulks list. This page states plainly what the injectable-route human studies actually found, and where the evidence runs out — no dose is recommended for anyone to take.

What it is

CJC-1295 is built on the first 29 residues of human growth-hormone-releasing factor, hGRF(1-29), with four amino-acid substitutions that stabilize its structure and block the enzyme (DPP-IV) that normally breaks it down within minutes. In the DAC ("Drug Affinity Complex") version, a chemical linker on the peptide's C-terminal lysine reacts with a free thiol on circulating albumin, permanently attaching the peptide to that albumin molecule and stretching its effective half-life out toward albumin's own multi-day lifespan. Strip out that linker and the result is the "no-DAC" form (also marketed as "Modified GRF 1-29"), which keeps the same four stabilizing substitutions but is short-acting because nothing holds it in circulation.

Both forms have only ever been studied by subcutaneous injection in humans. A 2010 analytical-chemistry paper identified CJC-1295 by high-resolution mass spectrometry as the active ingredient in an unlabeled "GHRH" product seized in an anti-doping investigation ^[7] — a reminder that this compound has circulated in unregulated markets since at least that year, with no oral or sublingual formulation ever characterized in the peer-reviewed literature.

How it works

CJC-1295 binds the growth-hormone-releasing hormone receptor on pituitary somatotroph cells, activating a Gs/cAMP/PKA signaling cascade that stimulates both synthesis and pulsatile release of growth hormone, which in turn raises liver-derived IGF-1. A 2025 review in a major endocrinology journal frames this as the general mechanistic template for the whole GHRH-analog class, which also includes sermorelin and tesamorelin ^[6].

The "pulsatile" part matters clinically: growth hormone is normally released in bursts, not a steady stream, and one early concern was that a long-acting GHRH stimulator might flatten that pattern into constant, non-physiological signaling. A dedicated human study found the opposite — the frequency and size of GH pulses were preserved even under continuous GHRH-analog stimulation from CJC-1295 ^[10].

What the research shows

Mechanism and pharmacology class. A 2024/2025 Nature Reviews Endocrinology paper synthesizes the pharmacology of GHRH and its synthetic analogs, covering receptor signaling and the design rationale behind long-acting variants like CJC-1295 ^[6].

Identification in an unregulated product. High-resolution LC-MS/MS work definitively identified CJC-1295 as the active ingredient in a seized, unlabeled "GHRH" preparation in an anti-doping context — direct evidence of how this compound circulates outside any approved supply chain ^[7].

Serum proteome shifts (human, n=11). In 11 healthy young men, subcutaneous CJC-1295 administration shifted several serum proteins (lower apolipoprotein A1 and a transthyretin isoform; higher C-terminal albumin fragment and immunoglobulin/beta-hemoglobin species), and one of those signals correlated linearly with IGF-1 — a candidate biomarker of GH-axis activation ^[8].

Dose-dependent GH/IGF-1 elevation (human). Single subcutaneous doses of 30 or 60 micrograms/kg in healthy adults produced 2- to 10-fold increases in plasma GH lasting six days or more, and 1.5- to 3-fold increases in IGF-1 lasting 9-11 days; with repeated dosing, IGF-1 stayed above baseline for up to 28 days, and the estimated half-life of CJC-1295 itself was 5.8-8.1 days ^[9].

Pulsatility preserved (human). In healthy men aged 20-40, a single subcutaneous dose (60 or 90 micrograms/kg) raised trough GH roughly 7.5-fold and mean GH and IGF-1 by about 45% a week later, while the underlying pulse frequency and pulse size of GH secretion were unchanged — evidence that continuous GHRH-receptor stimulation doesn't necessarily flatten the body's normal release pattern ^[10].

Every one of these findings comes from subcutaneous dosing. None of them can be used to infer what an oral, sublingual, or transdermal product would do, because that hasn't been tested.

Reported effects, cautions & safety

People using CJC-1295 in research-use communities describe a fairly consistent cluster of effects, almost all reported by people injecting it — anecdotal, not clinical evidence, and none of it tied to a verified dose.

Reported benefits: Deeper, more restful sleep is the single most commonly reported effect, often noticed within the first week, which tracks with the fact that growth hormone is released mainly during deep sleep. Faster recovery from training and reduced soreness, gradual fat loss (especially around the midsection, usually over three to six weeks), and a leaner look with better muscle retention while dieting are also frequently described. Reports of more daytime energy, sharper focus, and firmer-feeling skin or joints show up less consistently.

Reported adverse effects: Water retention, bloating, and facial or hand puffiness is the most common complaint, and users widely report it's worse with the long-acting DAC form than the short-acting no-DAC form — which lines up with DAC keeping growth hormone elevated for days rather than hours. Tingling or numbness in the hands, often compared to mild carpal tunnel, is frequently attributed to that same fluid retention pressing on wrist nerves. Injection-site reactions, occasional flushing or a warm "head rush" right after dosing (more with no-DAC), fatigue, headache, and, less often, increased appetite or higher blood sugar round out the list.

Cited cautions from the literature:

• Not approved for human use anywhere; published human evidence is limited to a handful of early pharmacology studies, not large or long-term trials ^[9][10].
• Sustained IGF-1 elevation carries a theoretical cancer concern — a large epidemiologic analysis linked higher circulating IGF-1 to modestly increased risk of certain cancers, a particular concern given how long the DAC form keeps IGF-1 elevated.
• Fluid retention and nerve-compression effects are a mechanistic consequence of growth hormone causing the kidneys to retain sodium and water.
• Effects on blood sugar and insulin sensitivity have been documented in GHRH-analog studies — a real consideration for anyone with diabetes or insulin resistance.
• The FDA flagged immunogenicity as part of its reasoning for not recommending CJC-1295 for a 503A compounding bulks list in 2024, alongside a current pharmacology review of the GHRH-analog class ^[6].
• A discontinued development program and a cited patient death are part of the compound's history; the public record does not establish that CJC-1295 caused that death, but the original long-acting program never reached approval.
• DAC and no-DAC forms are routinely confused in marketing, despite behaving completely differently in duration.
• Prohibited in sport at all times under WADA Section S2, with established detection methods.

Where it fits in delivery-route research

CJC-1295 sharpens the delivery-route question because it exists in two pharmacokinetically opposite forms sold under one name — and both have only ever been characterized by subcutaneous injection ^[9][10]. No published study has measured a sublingual or transdermal dose of either variant, so "sublingual CJC-1295" is, at present, an untested marketing claim rather than a documented alternative route. BPC-157 shares that same gap; semaglutide is the outlier with an actual verified oral pathway. See how the three stack up on the comparison page.