CJC-1295: real human data, measured one step short of an outcome

In plain terms

The pituitary gland releases growth hormone when it receives a signal from the brain. CJC-1295 is a synthetic copy of that signal, rebuilt so the body cannot break it down quickly. One version is also chemically attached to a blood protein, which stretches its action from minutes to days.

It works, in the narrow sense that it does what it was designed to do. In healthy volunteers, a single injection raised growth hormone for six days or more and raised IGF-1, the hormone growth hormone produces, for up to eleven ^[21].

That is a measurement of the machinery, not of a result. Nobody has published a trial asking whether people given CJC-1295 ended up with more muscle, less fat, better sleep or better function than people given a placebo. The hormone changes are well documented. The consequences are not documented at all, and this page ends by specifying the trial that would document them.

What it is

CJC-1295 is a synthetic analog of growth-hormone-releasing hormone, built on the first 29 residues of human growth-hormone-releasing factor. Four amino-acid substitutions — D-alanine at position 2, glutamine at 8, alanine at 15 and leucine at 27 — stabilise the helix and block cleavage by dipeptidyl peptidase IV as well as deamidation and oxidation.

Two forms share the name and they are not interchangeable. In the DAC form, standing for drug affinity complex, a C-terminal lysine carries a maleimidopropionyl linker that reacts with the free thiol on cysteine 34 of circulating albumin, forming a covalent peptide-albumin conjugate whose plasma half-life approaches that of albumin itself. The no-DAC form, usually called modified GRF 1-29, keeps the four substitutions but omits the albumin-binding group and is therefore short-acting. Confusing the two is the single commonest error in writing about this compound, and it is not a small one: the two differ in duration by orders of magnitude, so any statement about exposure that does not name the form describes nothing at all.

CJC-1295 is not approved for human use by any major regulator and is distributed as a research chemical. It was reviewed at the 2024 FDA Pharmacy Compounding Advisory Committee and was not recommended for the 503A compounding bulk substances list. It is prohibited in sport at all times under Section S2 of the World Anti-Doping Agency list, and detection methods are well established — indeed the compound has been identified by high-resolution mass spectrometry as the active ingredient of an unlabelled preparation seized in an anti-doping context ^[19].

How it works

CJC-1295 binds the growth-hormone-releasing hormone receptor on anterior-pituitary somatotrophs, activating Gs, cAMP and PKA signalling, which stimulates the synthesis and pulsatile release of growth hormone. Growth hormone in turn raises hepatic IGF-1.

The protease-resistant substitutions plus, in the DAC variant, covalent binding to albumin give it a multi-day half-life, so one administration keeps growth hormone and IGF-1 elevated for days while the pulsatile pattern of secretion persists.

A 2025 Nature Reviews Endocrinology review sets out the pharmacology of the whole class — receptor signalling, the rationale for long-acting analog design, and the therapeutic and investigational landscape for GHRH analogues including this one, sermorelin and tesamorelin ^[18].

For design purposes the important feature is what the mechanism makes easy to measure. Growth hormone and IGF-1 are both readily assayed in blood, which is why the human literature on this compound is unusually clean and unusually narrow. When a mechanism hands the investigator a convenient intermediate, the intermediate tends to become the endpoint, and the harder outcome study gets deferred.

What the research shows

Sorted by what each design could answer.

Human pharmacology and kinetics. In healthy adults, single subcutaneous administrations of 30 or 60 micrograms per kilogram produced dose-dependent 2- to 10-fold increases in mean plasma growth hormone lasting six days or more, and 1.5- to 3-fold increases in IGF-1 lasting nine to eleven days. After repeated administration IGF-1 remained above baseline for up to 28 days, and the estimated half-life of the compound was 5.8 to 8.1 days ^[21]. Those figures describe an experiment conducted under supervision so that a measurement could be taken; they are reported here as a description of that experiment and nothing else.

Human pharmacodynamics and secretion pattern. In healthy men aged 20 to 40, a single subcutaneous administration of 60 or 90 micrograms per kilogram raised trough growth hormone roughly 7.5-fold, mean growth hormone by about 46% and IGF-1 by about 45% one week later, while the frequency and magnitude of pulsatile secretion were unaltered ^[22]. The preserved pulsatility is a genuinely useful result, because it removes one anticipated objection to continuous GHRH-analog stimulation.

Human biomarker exploration. 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, identifying candidate markers of axis activation ^[20]. This is a detection and biomarker study, and it answers a detection question.

Class synthesis. The 2025 review places the compound within the GHRH-analog class and its investigational landscape ^[18].

Clinical outcomes. Nothing. Every human study listed above measured hormones, proteins or detectability. Not one measured body composition, physical function, sleep architecture or any other result a person would experience.

Reported effects, cautions and safety

What follows is anecdotal, not clinical evidence: research-use community reports, uncontrolled and unmeasured, presented without quantities and included because the contrast with the published endpoints is the point of this page.

On the benefit side, deeper and more restful sleep is very commonly reported. Faster recovery from training, gradual fat loss around the midsection, and a leaner appearance with better muscle retention are frequently reported. More daytime energy, improved focus, and a firmer feel to skin and connective tissue are reported occasionally. On the adverse side, water retention, bloating and puffiness are very commonly reported, and tingling or numbness in the hands and fingers, together with injection-site reactions, are frequently reported. Flushing shortly after administration, fatigue or drowsiness, headache, increased appetite, and higher blood sugar or reduced insulin sensitivity are reported occasionally.

Set that list beside the published endpoints and the mismatch is exact. The community reports are all outcomes — sleep, recovery, body composition, how hands feel. The literature contains only intermediates. Two of the commonest adverse reports, fluid retention and the carpal-tunnel-like tingling, are also the two most mechanistically predictable consequences of sustained growth-hormone signalling, which is a reason to take them seriously rather than to treat their absence from the trials as reassurance.

The cited cautions are these. CJC-1295 has never been approved for people by any major regulator and is sold only as a research chemical, with published human evidence limited to a small number of early pharmacology studies ^[21]. Immunogenicity, meaning the risk that the body mounts an immune response to the peptide, was among the safety concerns cited in the 2024 FDA advisory-committee briefing materials for this class ^[18].

The remaining cautions are carried without an attached citation and are reported on that basis: sustained IGF-1 elevation against a background epidemiological association between higher circulating IGF-1 and modestly increased risk of certain cancers; fluid retention, swelling and nerve-compression effects arising from growth-hormone-driven sodium and water retention; reduced insulin sensitivity and raised blood glucose, since growth hormone is glucose-sparing; the discontinued original development programme and the patient death frequently cited alongside it, for which no causal link was established in the public record; the routine conflation of the DAC and no-DAC forms; and prohibition in sport at all times.

Where it sits in the fundamentals

CJC-1295 occupies the human pharmacology row well and the rows above it not at all. Cell and animal rows are sparse. The observational row is empty. The pharmacology row holds three real human studies in healthy volunteers ^[20][21][22]. Randomised outcome trial: absent. Active comparator or long-term trial: absent.

That shape is the mirror image of BPC-157. BPC-157 has an enormous animal record and almost no human exposure; CJC-1295 has almost no animal record worth citing and a clean set of human pharmacology. Both end in the same place, for opposite reasons, and both are frequently described as well studied by people who have looked at the volume rather than the endpoints.

The surrogate problem is the general form of it. A surrogate is a measurement that stands in for the thing actually cared about, on the assumption that moving one moves the other. Growth hormone and IGF-1 are respectable surrogates with a real physiological basis. They are still an assumption, and an assumption is exactly what a trial exists to remove.

Design brief: the trial that would settle it

The claim to be tested is that sustained GHRH-analog stimulation produces a change a person would notice.

• Name the form, in the first line of the design. DAC or no-DAC, stated at randomisation and in every report. The two differ in duration by orders of magnitude, and a literature that blurs them cannot accumulate. The published half-life of 5.8 to 8.1 days belongs to the DAC form ^[21] and to nothing else.
• Comparator. Randomised and placebo-controlled, with blinding maintained despite the fluid-retention effect, which is plausible enough to unblind a naive design.
• Endpoint. A clinical outcome, prespecified: body composition by a direct imaging method, measured physical function, or objectively recorded sleep. IGF-1 becomes a mechanistic covariate rather than the result. The whole deficiency of the existing record is that the surrogate was allowed to be the answer.
• Duration. Longer than the published pharmacology windows. Elevated IGF-1 persisting up to 28 days after repeated administration ^[21] tells the designer what the exposure looks like, not what months of it produce.
• Safety monitoring. Prespecified and mechanism-led: glucose and insulin sensitivity, fluid status, and anti-drug antibodies, the last because immunogenicity was explicitly raised for this class ^[18]. Pulsatility should be recorded rather than assumed preserved, since the finding that it persists comes from a single-administration study ^[22].
• A constraint worth stating. The original long-acting development programme was discontinued, so the one historical attempt at a clinical endpoint is not available in the public record. A new trial starts from the pharmacology, not from an inherited safety database.

This is the most tractable brief on the site. The population is healthy volunteers, the exposure is characterised, the assays exist and the duration is measured in months. The reason it has not been run is not that it is difficult.