CJC-1295: Engineered to Last for Days, Which Is Why It Never Travels Alone

In plain English

The body has a natural signal, growth-hormone-releasing hormone, that tells the pituitary gland to release growth hormone. It is destroyed within minutes.

CJC-1295 is a laboratory copy of the working end of that signal, with four amino acids swapped out so the enzymes that would normally chew it up cannot get a grip. One version goes further: it carries a chemical hook that latches onto albumin, the most abundant protein in blood, so the whole assembly drifts around for days instead of minutes.

That long duration is the entire point of the molecule, and it is measurable. In healthy adults, a single injection kept growth hormone elevated for six days or more and raised IGF-1 — the downstream hormone growth hormone triggers — for nine to eleven days ^[11].

It has never been approved for people anywhere. Its published human record is a handful of early pharmacology studies, and it is banned in sport at all times.

What it is

CJC-1295 is a synthetic analogue of human growth-hormone-releasing factor, built on the first 29 residues — hGRF(1-29) — with four amino-acid substitutions: D-alanine at position 2, glutamine at 8, alanine at 15 and leucine at 27. Those swaps stabilise the alpha-helix and block cleavage by dipeptidylpeptidase-IV as well as deamidation and oxidation.

Two distinct molecules travel under one name, and confusing them is the single most consequential error a reader can make here.

• The DAC form carries a maleimidopropionyl linker on a C-terminal lysine, which undergoes Michael addition with the free thiol on Cys34 of circulating serum albumin. The result is a covalent peptide-albumin conjugate whose plasma half-life approaches albumin's own.
• The no-DAC form, usually sold as Modified GRF 1-29, keeps the four substitutions but has no albumin-binding arm. It is short-acting, and behaves nothing like its long-acting namesake.

CJC-1295 has never been approved by any major regulator for human use. It was reviewed at the 2024 FDA Pharmacy Compounding Advisory Committee and not recommended for the section 503A compounding bulks list. It is prohibited in sport at all times under WADA section S2, and it is detectable: the compound was structurally identified by high-resolution LC-MS/MS as the active ingredient in an unknown 'GHRH' pharmaceutical preparation seized in an anti-doping context ^[9].

How it works

CJC-1295 binds the growth-hormone-releasing hormone receptor on somatotroph cells in the anterior pituitary. That receptor is a G-protein-coupled receptor: engaging it activates Gs, raises cyclic AMP, and switches on protein kinase A, which drives synthesis and pulsatile release of growth hormone. Growth hormone in turn raises IGF-1 production in the liver.

The design goal was not a different signal but a longer one. A 2025 review in Nature Reviews Endocrinology synthesises the pharmacology of GHRH and its synthetic analogues — the class that also contains sermorelin and tesamorelin — covering receptor signalling, the rationale behind long-acting analogue design, and the therapeutic and investigational landscape for the class ^[8].

One finding matters more than its citation count suggests. Sustained stimulation of a pulsatile system might have been expected to flatten the pulses. It did not: in healthy men aged 20 to 40, a single subcutaneous dose left both the frequency and the magnitude of pulsatile growth-hormone secretion unaltered while raising the underlying levels, indicating that pulsatility survives continuous GHRH-analogue stimulation ^[12]. That is the pharmacological fact the pairing argument on this page is built on, and it is worth knowing that it is a real, measured result rather than an assumption.

What the research actually shows

The defining human study is a single-dose pharmacology trial, and its numbers are the ones everything else quotes. In healthy adults aged 21 to 61, single subcutaneous doses of 30 or 60 micrograms per kilogram produced dose-dependent increases in mean plasma growth hormone of two- to ten-fold, sustained for six days or more, and increases in IGF-1 of 1.5- to three-fold sustained for nine to eleven days. After multiple doses, IGF-1 remained above baseline for as long as 28 days. The estimated half-life of CJC-1295 itself was 5.8 to 8.1 days ^[11].

A second study fills in the pulsatility question. In healthy men aged 20 to 40, a single subcutaneous dose raised trough growth hormone roughly 7.5-fold, mean growth hormone by about 46% and IGF-1 by about 45% measured one week later, with pulsatile secretion unchanged in frequency and magnitude ^[12].

A proteomics study identified candidate biomarkers of the effect. In 11 healthy young adult men, administration shifted the serum proteome — apolipoprotein A1 and a transthyretin isoform decreased, a C-terminal albumin fragment and immunoglobulin and beta-haemoglobin species increased — and the immunoglobulin and albumin-fragment signal correlated linearly with IGF-1 ^[10].

And that is close to the whole human record. There is no large trial, no long-term safety database, and no outcome study in healthy adults. The original long-acting development programme ran a phase 2 trial in HIV-associated visceral obesity that was discontinued; a patient death during the development era is frequently cited alongside the halted programme, though the public record does not establish that CJC-1295 caused it. The load-bearing fact is simply that the drug never advanced to approval.

Most dosing schedules circulating online are not derived from controlled human trials, because there are almost no controlled human trials to derive them from.

What users report, and what the cautions say

What follows is anecdotal, not clinical evidence: self-reported patterns from peptide-user forums, clinic write-ups summarising client feedback and consumer guides. No dose is described and nothing here was measured under controlled conditions.

Deeper, more restful sleep is very commonly reported and is usually the first effect people mention, sometimes within the first week — a claim that at least sits comfortably alongside the known biology, since growth hormone is released mainly during deep sleep. Faster recovery between hard training sessions and gradual fat loss around the midsection are both frequently reported, with the fat-loss reports typically describing changes from around weeks three to six and only alongside diet and exercise. A leaner look and better muscle retention while dieting are frequently reported. More daytime energy and sharper focus are occasionally reported, usually attributed by the people reporting them to sleeping better rather than to any direct effect. Firmer-feeling skin and better-conditioned connective tissue are occasionally reported.

On the adverse side, water retention is very commonly reported and is the community's signature complaint: mild bloating, a heavier feeling, puffiness in the hands and face. It is widely described as more pronounced with the long-acting DAC form than with the short-acting no-DAC form, which fits the pharmacology — the DAC form keeps growth hormone elevated for days ^[11]. Tingling or numbness in the fingers, often compared to mild carpal tunnel, is frequently reported and generally attributed to that same fluid retention. Injection-site reactions are frequently reported. Flushing or a brief head-rush after injection, fatigue or drowsiness, and headache are each occasionally reported. Increased appetite is occasionally reported and — this is the interesting one — communities generally attribute it to the ipamorelin partner rather than to CJC-1295 itself, since it appears mainly when the two are used together. Higher blood sugar or reduced insulin sensitivity is occasionally reported, and flagged as a particular concern for people with existing blood-sugar problems.

The documented cautions:

• Not approved for human use anywhere. Published human evidence is limited to a small number of early pharmacology studies; no large or long-term trial has shown it to be safe or effective in healthy adults ^[11]. It is investigational, not a proven therapy.
• Sustained IGF-1 elevation and a theoretical cancer concern. A large epidemiological meta-analysis linked higher circulating IGF-1 to a modestly increased risk of certain cancers, and the long-acting form keeps IGF-1 elevated for days. That is an association from population data, not proof that this compound causes cancer, but it is a mechanism-based concern for anyone with a personal or family history of malignancy.
• Fluid retention, swelling and nerve compression. Growth hormone makes the kidneys retain sodium and water, expanding fluid volume — the likely reason the water-retention and carpal-tunnel-like reports are so consistent. For people prone to swelling, high blood pressure or cardiac strain this is a real mechanism-based concern rather than a cosmetic one.
• Blood sugar and insulin sensitivity. Growth hormone is glucose-sparing, so sustained stimulation of the axis can reduce insulin sensitivity and raise blood sugar.
• Immunogenicity flagged by regulators. In 2024 FDA briefing materials for the Pharmacy Compounding Advisory Committee, immunogenicity — the risk of an immune response to the peptide itself — was cited among the safety concerns behind the decision not to recommend CJC-1295 for the 503A bulks list; the current pharmacology review of the class reinforces that long-acting albumin-binding designs carry such considerations ^[8].
• A discontinued programme and an unresolved death, described above.
• DAC and no-DAC are routinely confused. Marketing and forums treat the two as interchangeable when they are not, and the duration difference is what drives the sustained fluid retention, glycaemic shifts and IGF-1 exposure. Knowing which form is in hand is a precondition for interpreting any reported effect at all.
• Prohibited in sport at all times under WADA section S2, with established detection methods.

Why it ends up coupled to something else

CJC-1295 is half of a pairing so familiar that many readers meet the two names as a single phrase before they meet either compound on its own.

The mechanistic argument is the strongest one available on this site. CJC-1295 acts at the GHRH receptor ^[8]. Ipamorelin acts at the ghrelin receptor, a different receptor on the same pituitary cells, and produces its own discrete growth-hormone pulse ^[16]. Two independent inputs to one output is a coherent design idea, and it is reinforced by the measured finding that pulsatile secretion persists under continuous GHRH-analogue stimulation rather than being flattened by it ^[12].

The duration difference is the other half of the argument: the DAC form's estimated 5.8- to 8.1-day half-life provides a sustained background ^[11], while ipamorelin's roughly two-hour terminal half-life provides a short pulse ^[16]. Long plus short is, in the abstract, a sensible way to build a signal.

And here the trail goes cold. No study on this desk's source list administered the two together and measured anything. The pairing rests on the separate single-agent pharmacology of the two compounds, which is a description of a rationale, not a result. What is more, the risks the two carry are not complementary at all — they overlap. Both raise growth hormone and therefore IGF-1 exposure; both come with fluid-retention and glucose concerns in their own safety records. The hoped-for benefits are assumed to add. The documented risks demonstrably do.

That asymmetry is the reason this desk treats the familiar pairing as an open question rather than a settled design.