# CJC-1295: what happens when you stretch the clock > CJC-1295 — Growth Hormone Axis research peptides | skyhighpeptides — CJC-1295 in the literature: a GHRH analogue engineered for a multi-day half-life, and the one human study that measured whether growth-hormone pulsatility survived it. Mechanism, DAC versus no-DAC, evidence and cautions — from the skyhighpeptides digest of Growth Hormone Axis research peptides. **02 · ANSWER TWO: DURATION** A GHRH analogue redesigned to bond covalently to serum albumin and stay in circulation for days. The question that makes it interesting is not how high growth hormone goes, but whether the pulse underneath survives. ## The short version CJC-1295 is a laboratory-modified copy of the body's own growth-hormone-releasing hormone, GHRH. The natural signal is fragile — enzymes in the blood break it apart within minutes. CJC-1295 carries four amino-acid swaps that block those enzymes, and one version carries an extra chemical hook that **latches permanently onto albumin**, the most abundant protein in blood. Hitching a ride on albumin is what turns a signal lasting minutes into one lasting days. That creates an obvious worry. Growth hormone is supposed to come in bursts. A drug that presses the release button continuously for a week ought to flatten the bursts into a plateau — and a flat hormone level is exactly what the secretagogue approach was meant to avoid. Researchers measured it. In healthy young men, a single dose raised baseline growth hormone sharply and held IGF-1 up for a week, yet the *frequency and size of the pulses themselves were unchanged* [12]. The floor came up; the beat kept beating. That result is the most interesting thing about this compound. It is also a single study, in healthy young men, measuring hormone levels rather than health outcomes. ## What it is CJC-1295 is built on hGRF(1–29), the first 29 residues of human growth-hormone-releasing factor. Four substitutions — D-Ala at position 2, Gln at 8, Ala at 15 and Leu at 27 — stabilise the molecule's alpha-helix and block dipeptidylpeptidase-IV cleavage, deamidation and oxidation. The critical distinction, and the one most consistently mangled online, is **DAC versus no-DAC**. - *CJC-1295 with DAC* ("Drug Affinity Complex") adds a C-terminal lysine functionalised with a maleimidopropionyl linker. That linker undergoes Michael addition with the free thiol on Cys34 of circulating serum albumin, forming a covalent peptide-albumin conjugate whose half-life approaches albumin's own [19]. - *CJC-1295 no-DAC*, usually sold as "Modified GRF 1-29", keeps the four substitutions but omits the albumin hook. It is short-acting, on the order of half an hour. These two are not variants of a theme; they are pharmacokinetically different compounds that happen to share a name. Marketing and forums treat them as interchangeable, and that conflation matters, because the long duration of the DAC form is what drives sustained fluid retention, sustained IGF-1 exposure and sustained metabolic effects. CJC-1295 is not approved for human use by the FDA or any major regulator. It was reviewed, and not recommended, for the Section 503A compounding bulks list at the 2024 Pharmacy Compounding Advisory Committee. It is prohibited in sport at all times under WADA Section S2, with well-established detection assays — indeed, it was structurally identified by high-resolution LC-MS/MS as the active ingredient in an unidentified "GHRH" preparation seized in an anti-doping context [9]. ## How it works: raising the floor, not the beat CJC-1295 binds the GHRH receptor on anterior-pituitary somatotrophs — a class-B G-protein-coupled receptor — and activates Gs/cAMP/PKA signalling, which stimulates both the synthesis and the pulsatile release of growth hormone. Downstream, growth hormone drives hepatic IGF-1 production. The 2025 *Nature Reviews Endocrinology* review of GHRH and its analogues covers that receptor biology, the design rationale for long-acting analogues, and the therapeutic landscape the class sits in [8]. The albumin chemistry is what separates CJC-1295 from every other GHRH analogue. In rats, the maleimidopropionamide-lysine conjugate produced roughly a four-fold increase in growth-hormone area-under-the-curve over two hours compared with unmodified hGRF(1–29), with albumin-bound peptide still detectable in plasma beyond 72 hours [19]. Extend that in humans and a single injection becomes a week-long stimulus. Here is the conceptual pivot, and it is the reason this compound belongs at the centre of a site about pulsatility. Continuous receptor stimulation is normally the enemy of pulsatile output — that is a general principle of endocrine pharmacology, and it is why chronic uninterrupted GHRH exposure in other settings has blunted the response. CJC-1295 appears to be an exception, and the reason is that it is not overriding the pituitary's own rhythm generator. Somatostatin is still cycling, feedback is still intact, and the analogue simply raises the level from which each pulse departs [12]. **Amplitude modulation, not pattern replacement.** The qualifier: that finding rests on one published study in healthy 20- to 40-year-old men, over one week. It has not been replicated across ages, sexes, dosing durations or clinical populations. ## What the research shows **The pharmacokinetic anchor.** In healthy adults aged 21–61, single subcutaneous doses 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 9–11 days. After multiple doses IGF-1 remained above baseline for up to 28 days, and the estimated half-life of CJC-1295 itself was 5.8–8.1 days [11]. This is the study every claim about the compound's duration ultimately rests on. **The pulsatility test.** In healthy men aged 20–40, a single subcutaneous dose of 60 or 90 micrograms per kilogram raised trough/basal growth hormone approximately 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. The authors' conclusion is the one this site is organised around: pulsatility persists during continuous stimulation by a long-acting GHRH analogue [12]. **Biomarkers, not outcomes.** In 11 healthy young adult men, CJC-1295 shifted the serum proteome — apolipoprotein A1 and a transthyretin isoform fell; a C-terminal albumin fragment and immunoglobulin and beta-hemoglobin species rose — and the immunoglobulin/albumin-fragment signal correlated linearly with IGF-1, identifying candidate biomarkers of axis activation [10]. Useful for anti-doping science. Not evidence of benefit. **Analytical chemistry, not clinical trials.** The identification of CJC-1295 in a seized black-market preparation [9] is included here deliberately, because it is an accurate portrait of where this compound actually lives: in an unregulated supply chain, characterised more often by forensic chemists than by trialists. Note what is *absent* from that list. There is no controlled trial of CJC-1295 in healthy adults for body composition, recovery, sleep or aging. The original long-acting DAC development programme ran a Phase 2 trial in HIV-associated visceral obesity that was discontinued, and it never advanced to approval. Every human dataset above measures hormones, proteins or pharmacokinetics — surrogate endpoints, uniformly. ## Reported effects, cautions and safety The community record below is **anecdotal, not clinical evidence**: self-reported, unverified as to substance, purity or protocol, and included for completeness rather than as support for anything. Deeper and more restful sleep is the single most commonly reported effect and usually the first one noticed, which at least rhymes with the biology, since growth hormone is released mainly during slow-wave sleep. Faster recovery from training and reduced soreness is frequently reported. Gradual fat loss around the midsection, a leaner look with better muscle retention while dieting, more daytime energy, sharper focus and firmer-feeling skin are all reported with decreasing frequency and increasing confounding. On the adverse side, water retention, bloating and puffiness is the most commonly reported downside, and communities consistently describe it as worse with the long-acting DAC form than with short-acting no-DAC — which is precisely what a multi-day growth-hormone elevation would predict. Tingling or numbness in the fingers, compared to mild carpal tunnel, is frequently reported and generally attributed to that same fluid retention. Injection-site reactions are common and minor. Flushing or a warm head-rush is reported more around no-DAC dosing; fatigue or drowsiness more with DAC. Headache, increased appetite (mostly when ipamorelin is in the mix) and higher blood sugar round out the list. The cited and reasoned safety picture: **Nothing here is approved, and the human record is thin.** CJC-1295 has never been approved by the FDA or any major regulator for people. Published human evidence amounts to a handful of early pharmacology studies [11][12][10]; there are no large or long-term trials of safety or efficacy in healthy adults. It should be read as investigational, not as a therapy with an unfavourable label. **Sustained IGF-1 elevation carries a theoretical oncologic concern.** Growth hormone and IGF-1 are proliferative signals, and population epidemiology has linked higher circulating IGF-1 with modestly increased risk of certain cancers. Because the DAC form keeps IGF-1 elevated for days after a single dose [11], the exposure is not transient. This is an association drawn from population data plus a mechanism — not proof that this compound causes cancer, and not something any trial of this compound has looked for. **Fluid retention has a real mechanism behind it.** Growth hormone promotes renal sodium and water retention, which expands extracellular fluid volume. That is the likely basis for the puffiness and carpal-tunnel-like tingling reported so consistently, and it makes the symptom a genuine mechanistic concern in anyone prone to swelling, hypertension or cardiac strain rather than a cosmetic annoyance. **Blood sugar moves the wrong way.** Growth hormone is glucose-sparing, so sustained axis stimulation can reduce insulin sensitivity and raise blood glucose. Clinical work on GHRH analogues has documented effects on insulin sensitivity, and prolonged stimulation is the scenario of most concern for anyone with diabetes, prediabetes or insulin resistance. **Regulators have flagged immunogenicity.** FDA briefing materials for the 2024 Pharmacy Compounding Advisory Committee cited immunogenicity — the risk of the body mounting an immune response to the peptide — among the safety concerns behind not recommending CJC-1295 for the 503A compounding bulks list. Current pharmacology reviews of the GHRH-analogue class note that long-acting, albumin-binding designs carry exactly this kind of consideration [8]. It is a regulator-level concern rather than a settled clinical finding, and it is not resolved. **The development history is unresolved, not exonerating.** The original DAC programme was discontinued, and a patient death during the development era is frequently cited alongside the halted trial. The public record does not establish that CJC-1295 caused it. The defensible statement is the narrow one: the programme stopped, the compound was never approved, and the question was never closed. **Know which form is in hand.** Because DAC and no-DAC differ by days versus minutes [19], every reported effect, every safety inference and every duration claim is unreadable without knowing which one is being discussed. ## Where it fits in the growth hormone axis CJC-1295 is the duration answer, and it is the compound that turned pulsatility from an assumption into a measured question. If a week-long GHRH stimulus had flattened the pulse, the entire "more physiologic than exogenous growth hormone" argument would have collapsed for long-acting analogues. It did not [12], and that single result carries a great deal of the intellectual weight in this category. What it does not do is produce a bigger pulse. It raises the floor the pulses stand on — a different intervention with a different consequence, because a raised floor means sustained IGF-1 exposure rather than intermittent spikes, and sustained exposure is what most of the safety discussion above is actually about. That is precisely the gap the ghrelin arm is meant to fill, and why the two are so often run together. See [Ipamorelin](/ipamorelin) for the sharp-beat answer, the [CJC-1295 / Ipamorelin](/cjc1295-ipamorelin) page for the attempt to have both, or [compare these peptides](/compare) in one table. --- A literature digest on the growth-hormone axis, written to keep the pulse — and the evidence behind it — in proportion; not a clinic, not a pharmacy, and not medical advice.