# CJC-1295: Research Overview — Long Island Peptides

> A literature digest of CJC-1295, a long-acting GHRH analog studied for sustained growth-hormone and IGF-1 elevation. Covers mechanism, the DAC albumin-binding chemistry, human pharmacology data, and cited safety cautions.

A long-acting GHRH analog whose defining trick is chemistry: bind to serum albumin, and a single dose can keep growth hormone elevated for days.

## The short version

CJC-1295 is a lab-made version of a natural signal called GHRH — growth-hormone-releasing hormone — engineered to last far longer in the body than the original. Four small changes to its amino-acid chain stop enzymes from breaking it down quickly, and in its most common research form, it is also chemically bonded to **albumin**, a protein that circulates in blood for days. That bond is why a single dose can keep growth hormone elevated for close to a week, instead of the few minutes natural GHRH lasts.

Human research on CJC-1295 is limited to a handful of small pharmacology studies from the mid-2000s in healthy volunteers — it has never been approved by the FDA or any regulator, and it is sold only as a research chemical. This page walks through what those studies found, what people in research-use communities report anecdotally, and the safety questions that come with sustained growth-hormone stimulation. It does not recommend a dose for anyone.

## What it is

CJC-1295 is built on the first 29 amino acids of human growth-hormone-releasing hormone, hGRF(1-29), with four substitutions — at positions 2, 8, 15, and 27 — that stabilize its alpha-helix shape and block the main routes of natural breakdown: cleavage by the enzyme dipeptidyl peptidase-IV (DPP-IV), deamidation, and oxidation [2][7]. Those four changes alone extend its activity somewhat, and that short-acting version is sometimes sold separately as "Modified GRF (1-29)" or "no-DAC" CJC-1295.

The form usually meant by the plain name "CJC-1295," though, adds one more piece: a maleimidopropionyl linker at the tail end of the molecule that reacts with a specific site (Cys34) on serum albumin, the most abundant protein in blood plasma. Once that bond forms, the peptide is carried along with the albumin molecule itself, which is why researchers call this the "DAC" — Drug Affinity Complex — variant. It was first pinned down analytically in 2010, when researchers used high-resolution mass spectrometry to identify CJC-1295 as the active ingredient in an unlabeled product seized in an anti-doping investigation [2].

## How it works

CJC-1295 binds the growth-hormone-releasing hormone receptor (GHRHR) on somatotroph cells in the anterior pituitary gland. That binding activates a Gs-protein/cyclic-AMP/protein-kinase-A signaling cascade — the same pathway natural GHRH uses — which drives those cells to both synthesize new growth hormone and release what they are already holding. Because the DAC-albumin bond keeps the peptide circulating for days rather than minutes, a single dose produces a stimulus to the pituitary that is unusually sustained for a hormone system that normally works in short pulses.

One open question researchers specifically checked: does that sustained stimulus flatten out the normal pulsatile rhythm of GH release, or does the pituitary keep pulsing on top of it? A 2006 human study found the pulsatile pattern of GH secretion persisted largely unchanged even under continuous CJC-1295 stimulation — trough (baseline) GH rose roughly 7.5-fold, but the pulses riding on top of that new baseline kept their usual frequency and shape [5]. That distinction — a raised floor, not a flattened rhythm — is central to how researchers interpret CJC-1295's effect on the GH axis.

## What the research shows

The most current framing of CJC-1295's pharmacology comes from a 2025 review in Nature Reviews Endocrinology, which synthesizes GHRH-analog receptor signaling and the therapeutic and investigational landscape for the whole drug class, CJC-1295 included [1]. Its identity as a compound was nailed down analytically in 2010, when LC-MS/MS analysis identified CJC-1295 as the active ingredient in an unlabeled preparation seized in an anti-doping context — a demonstration that established, unambiguous detection methods exist for it [2].

The core human pharmacology dates to 2006. In healthy adults aged 21 to 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 to 11 days; after repeated dosing, IGF-1 stayed above baseline for up to 28 days. The same study estimated CJC-1295's half-life at 5.8 to 8.1 days [4]. A companion study in healthy men aged 20 to 40 found that a single 60 or 90 microgram/kg dose raised basal GH roughly 7.5-fold and mean GH and IGF-1 by about 46% and 45% respectively one week later, while confirming that pulsatile GH secretion continued at its normal frequency [5].

Earlier work in 11 healthy young men found CJC-1295 shifted several serum proteins — including a rise in an albumin fragment and immunoglobulin-related species that correlated directly with IGF-1 levels — a finding researchers read as a candidate biomarker set for GH/IGF-1 axis activation [3]. In GHRH-knockout mice, once-daily CJC-1295 fully normalized body weight and length, while less frequent dosing (every 48-72 hours) was progressively less effective, underscoring how much the DAC chemistry's duration matters to the biological effect [6]. And the foundational chemistry paper showed that, in rats, the albumin-conjugated form produced a 4-fold increase in growth-hormone output over two hours compared with unconjugated hGRF(1-29), with the peptide still detectable in plasma beyond 72 hours [7].

## Reported effects, cautions & safety

**Reported effects (anecdotal, not clinical evidence):** deeper, more restful sleep is by far the most frequently mentioned effect in research-use community reports, and people often say it is the first thing they notice — a pattern that lines up with the fact that growth hormone is released mainly during deep sleep. Faster recovery between workouts and reduced soreness are also frequently mentioned, though these are harder to separate from a simple side effect of sleeping better. Slow, gradual fat loss over several weeks — usually described as showing up around weeks three to six and usually paired with diet and exercise — and a leaner look with better muscle retention while dieting round out the most common reported benefits. Reports of more daytime energy and sharper focus are less consistent, and some people describe firmer skin or joint comfort, tied to the general anti-aging framing that surrounds GH-axis peptides. None of this comes from a controlled trial.

On the downside, water retention and puffiness are the most consistently reported complaint, and communities widely describe it as worse with the long-acting DAC form than the short-acting no-DAC form — which tracks with DAC keeping GH elevated for days rather than minutes. Tingling or numbness in the hands, often compared to mild carpal tunnel, and mild injection-site reactions are frequently mentioned. Less often, people describe a brief flush or "head rush" after injecting (more with the short-acting form), fatigue, headache, or — when CJC-1295 is paired with ipamorelin specifically — increased appetite that the community generally attributes to the ipamorelin half rather than CJC-1295 itself.

**Cited safety cautions:** CJC-1295 has never been approved by the FDA or any regulator, and published human evidence is limited to the small pharmacology studies above — there is no large or long-term trial establishing safety in healthy adults [4]. Because it raises GH and IGF-1, and population studies have linked higher circulating IGF-1 to a modestly increased risk of certain cancers, researchers flag a mechanism-based (not proven) concern for anyone with a personal or family history of cancer. Growth hormone also causes the kidneys to retain sodium and water, which is the likely mechanism behind the community reports of bloating and carpal-tunnel-like tingling above, and a real concern for anyone prone to swelling or heart strain. Sustained GH stimulation is understood, mechanistically, to reduce insulin sensitivity — a caution that a 2011 study of the related GHRH analog tesamorelin helps illustrate, even though that specific trial did not test CJC-1295 [18]. FDA briefing materials from a 2024 compounding-pharmacy advisory committee cited immunogenicity concerns for CJC-1295 specifically, and the current pharmacology review of the GHRH-analog class reinforces that long-acting, albumin-binding designs carry such considerations [1]. The original long-acting CJC-1295 DAC development program was itself discontinued, with a patient death during that era frequently cited alongside the halted trial — though the public record does not establish that CJC-1295 caused it. Researchers also flag that marketing routinely conflates the DAC and no-DAC forms, which matters because the DAC chemistry is specifically what drives the multi-day duration described above [7]. Finally, CJC-1295 is prohibited in sport at all times under WADA's peptide-hormone category, with established detection methods.

## Where it fits in the Growth Hormone Axis

CJC-1295 is the anchor compound on this guide — the long-acting GHRH-receptor analog that the other three are read against. Its relationship to [tesamorelin](/tesamorelin) is instructive: both are modified GHRH analogs, but tesamorelin is dosed daily and carries FDA approval for one specific indication, while CJC-1295's multi-day albumin-bound duration has never gone through that same regulatory process. Because GHRH-receptor and ghrelin-receptor signaling are independent pathways, CJC-1295 is also the GHRH half of [CJC-1295/Ipamorelin](/cjc1295-ipamorelin), the most-discussed combination in this space, pairing it with the selective ghrelin-receptor agonist [ipamorelin](/ipamorelin). See how all four stack up on the [comparison page](/compare).

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Long Island Peptides is an independent field guide to GH-axis research — every claim here arrives with its citation, and every citation arrives with its caveat.