CJC-1295: The DAC Question, the Human Data, and the Regulatory Reality

What is CJC-1295?

CJC-1295 is a laboratory-made analog of growth-hormone-releasing hormone — the signal your hypothalamus normally sends to the pituitary to release a pulse of growth hormone (GH). It is not GH itself. It is an upstream trigger, engineered to survive far longer in the bloodstream than the natural hormone it copies.

Native GHRH is a 44-amino-acid peptide, but its first 29 residues — the fragment called GRF(1-29) — carry essentially all of its GH-releasing activity. That fragment is also the basis of the approved drugs sermorelin and tesamorelin. The problem with a bare GRF(1-29) is that the body chews it up in minutes, largely through the enzyme dipeptidyl peptidase-4. CJC-1295 was designed to fix that. It carries four amino-acid substitutions on the GRF(1-29) backbone — including a D-alanine at position 2 that blocks that enzyme — which slow its breakdown, and then, in its defining form, a chemical linker that latches onto a protein in your blood so it is not cleared at all for days.

The compound came out of ConjuChem Biotechnologies, a Montreal company that in the early 2000s built a platform around exactly this trick of tethering short-lived peptides to albumin. GHRH is a peptide hormone — a signaling molecule, not a building block — which is why the discussion below is about how strongly and for how long CJC-1295 pushes the GH axis, never about the peptide being "absorbed" like a nutrient. It sits in the same broad family as the growth-hormone secretagogues discussed so heavily online, though it works through a different receptor.

CJC-1295 with DAC vs without DAC (mod GRF 1-29)

This is the single most confused point about the compound, and getting it right changes how you read everything else. There are two products sold under the CJC-1295 name, and they are not interchangeable.

CJC-1295 with DAC is the original molecule. DAC stands for Drug Affinity Complex: a small reactive chemical group attached to the peptide that, once injected, forms a covalent bond with serum albumin — the most abundant protein in your blood. Bound to albumin, the peptide is shielded from clearance and circulates for a long time. In the human study that measured it, the terminal half-life was on the order of 5.8 to 8.1 days. That is the version ConjuChem developed and the version every published human trial used.

CJC-1295 without DAC is a different animal. Strip off the DAC group and you are left with the tetra-substituted GRF(1-29) backbone — a peptide whose correct name is modified GRF 1-29. Without the albumin anchor it clears in roughly half an hour, producing a single short GH pulse rather than a multi-day elevation. Calling this "CJC-1295 no DAC" is a marketing convention that stuck; strictly, the DAC is the thing that makes CJC-1295 what it is, so the no-DAC product is really just modified GRF 1-29 wearing a more famous name.

Why it matters: when someone cites "the CJC-1295 human data," they are citing the DAC version. There is no comparable published human trial for the short-acting no-DAC peptide under any name. So the two products carry very different evidence — one has two small early-phase studies, the other has essentially none — even though they are sold side by side and discussed as if they were the same thing.

Does CJC-1295 actually work?

Split the question, because "work" means two different things.

Does it raise GH and IGF-1? Yes — that part is genuinely demonstrated in humans, for the DAC version. Both 2006 studies showed clear, sustained increases in growth hormone and its downstream marker IGF-1 after subcutaneous injection in healthy adults. That is a real pharmacological effect, not a claim from animal models.

Does raising GH and IGF-1 produce the outcomes people want? Unknown. The reasons people take CJC-1295 — more muscle, faster recovery, less fat, better sleep, "anti-aging" — were never the endpoint of any published trial. The human studies measured hormone levels and safety over days to weeks. Nobody ran the trial that would show whether a months-long course changes body composition, strength, injury recovery, or any clinical outcome in healthy people. So CJC-1295 does something measurable to your endocrine system, and whether that something is useful, useless, or harmful over time has not been established — a distinction easy to lose in marketing that quotes the IGF-1 numbers as if they were results.

What human evidence exists on CJC-1295?

Two studies. Both published in 2006, both in the Journal of Clinical Endocrinology & Metabolism, both on the DAC version, both small, both in healthy volunteers rather than patients. That is the entire published human record.

The second study asked a subtler, important question: if you keep GHRH switched on for days, does the pituitary keep pulsing GH the way it should, or does it flatten out? Ionescu and Frohman found that pulsatile GH secretion persisted during continuous stimulation by CJC-1295. The frequency and amplitude of natural GH pulses were unchanged; what rose was the trough — baseline GH between pulses jumped roughly 7.5-fold — lifting mean GH by about 46% and IGF-1 by about 45%. Preserving pulsatility matters because injected GH itself shuts pulsing down, and pulsatile signaling is part of normal physiology.

Note what is missing. Both studies are short. Both are in healthy people. Neither was designed to test a benefit. There is no published human pharmacokinetic or efficacy trial of the no-DAC modified GRF 1-29 product, and no long-term follow-up of anyone on CJC-1295 for any length of time. The identity and analytical characterization of the compound have been documented largely in the context of anti-doping detection work, not clinical development.

How is CJC-1295 thought to work?

The mechanism here is better understood than for most gray-market peptides, because it hijacks a well-mapped physiological pathway rather than a speculative one.

• GHRH receptor activation. CJC-1295 binds the GHRH receptor on the somatotroph cells of the anterior pituitary — the same receptor native GHRH, sermorelin and tesamorelin use — prompting those cells to synthesize and release growth hormone.
• Albumin tethering (DAC form). The DAC group's covalent bond to albumin turns a minutes-long signal into a days-long one, so instead of a single pulse you get a sustained lift in the baseline around which the pituitary keeps pulsing.
• Downstream IGF-1. The elevated GH drives the liver to produce more IGF-1, the hormone that mediates many of GH's growth and metabolic effects and the marker used to track the axis in both 2006 studies.
• Preserved feedback, mostly. Because CJC-1295 acts one step upstream of GH, the pituitary's own pulse generator and the normal negative-feedback loops stay partly intact — a contrast with injecting GH directly, and a recurring theme in reviews of growth-hormone secretagogues in the modern clinic.

The catch built into that elegance: chronically raising the trough level of a pulsatile hormone is not the same as restoring youthful physiology, and the long-term consequences of keeping IGF-1 elevated for months are exactly what no study has measured.

Why was CJC-1295 never approved?

CJC-1295 did not fail a phase III trial. It never reached one. The two 2006 papers represent early-phase clinical evaluation — the kind of first-in-human pharmacology and safety work that sits near the start of the drug-development pipeline. To become an approved medicine, a compound then has to run large, controlled phase II and phase III trials proving it produces a real clinical benefit at an acceptable risk, for a defined condition. That program was never completed for CJC-1295, and the developer discontinued it.

Absence of a completed program is not proof a compound is unsafe — but it is not a footnote either. It means the questions those trials exist to answer were never answered: what dose does what, over what timeframe, in whom, at what rate of harm. Tesamorelin, a GHRH analog that reached the market, only got there by finishing that work. CJC-1295 stopped long before it, so everything sold today trades on early-phase data never meant to support routine use in healthy people.

Is CJC-1295 FDA approved or legal?

CJC-1295 is not approved as a drug by the FDA, the EMA, or any other national regulator, and it is not a legal dietary supplement in the United States, because a substance investigated as a drug cannot be marketed as a supplement. Its regulatory status has recently moved through the same compounding process that has swept up several research peptides:

• 503A Category 2. CJC-1295 was placed on the FDA's Category 2 list — bulk drug substances that "may present significant safety risks" — which meant compounding pharmacies could not legally prepare it. The stated concerns for this class of peptides centered on insufficient safety data, and questions about identity, purity and characterization.
• December 2024: advisory vote against. The FDA's Pharmacy Compounding Advisory Committee reviewed CJC-1295 and voted against recommending it for the list of substances eligible for 503A compounding.
• April 2026: removed from Category 2. In a reorganization of the bulk-substance lists, CJC-1295 was taken off the Category 2 list — but it was not moved onto the permitted (Category 1) list. It sits in a reconsideration limbo, which is procedural housekeeping, not an endorsement, and does not create a lawful 503A or 503B basis to compound it in the meantime.

Keep two things straight. Removal from a restricted list is not the same as approval, and neither event changes the evidence base by a single study. Separately, in sport, CJC-1295 is prohibited: the World Anti-Doping Agency bans growth-hormone-releasing factors and their analogs under class S2, at all times and by every route, so a positive test is a violation regardless of amount. Most CJC-1295 sold online is labeled "for research use only, not for human consumption" — wording that shields the seller and guarantees nothing about what is in the vial. For how these categories fit together, see our overview of whether peptides are legal.

CJC-1295 side effects and the safety unknowns

Two statements are both true and easy to blur together.

The trials reported little. Across the two 2006 studies, the most common adverse events were injection-site reactions — transient pain, swelling, redness and firmness at the injection site. No severe or unexpected safety signal was reported over the short study periods, and the drug was characterized as relatively well tolerated.

That is not a safety profile. Two small, short studies in healthy volunteers cannot tell you what months of elevated GH and IGF-1 do to a person. The meaningful risks are the well-known class effects of growth-hormone excess, seen in acromegaly and in GH therapy, which a drug that chronically raises GH could plausibly produce:

• Fluid retention and joint symptoms. Edema, puffiness, arthralgia, and carpal-tunnel-type numbness and tingling are classic consequences of raised GH.
• Insulin resistance. Growth hormone opposes insulin, so sustained elevation can reduce insulin sensitivity and raise blood glucose — a particular concern for anyone with prediabetes or diabetes.
• IGF-1 and proliferation. IGF-1 is a growth signal. There is no evidence CJC-1295 causes cancer and no study designed to look, but chronically elevating a mitogenic hormone without long-term data is a theoretical concern reviewers consistently flag, and a history of cancer is a standard reason to avoid GH-raising agents.
• Product quality. Gray-market vials carry unverified identity, purity and sterility — the exact impurity-and-characterization issues the FDA named for this peptide class.

CJC-1295 vs sermorelin, tesamorelin and ipamorelin

The growth-hormone-axis peptides get lumped together, but they differ in receptor, duration, and — crucially — how much human evidence stands behind each. The table compares them on what has actually been tested.

The two GHRH analogs that reached patients did so with real trial programs. Sermorelin was an approved drug used to diagnose and treat GH deficiency in children and to test pituitary function; earlier work showed once-daily GHRH could accelerate growth in deficient kids. Tesamorelin stays FDA-approved for a defined condition after phase III trials showed it reduced abdominal visceral fat in HIV-associated fat accumulation, with a follow-up tracking its effect on visceral and liver fat. Ipamorelin is the mechanistic outlier — a selective GH secretagogue at the ghrelin receptor, which is why the no-DAC form is so often paired with it, though that combination has no human outcome data.

How long does CJC-1295 take to work?

If "work" means moving the hormone, the pharmacology is quick and durable: in the trials, GH climbed within hours of a DAC-version injection and IGF-1 rose over the following days and stayed elevated for a week or more, which is the entire point of the albumin-binding design. That is a well-documented time course for the biochemistry.

If "work" means the visible results people chase — recovery, body composition, sleep — there is no evidence-based timeline, because no trial measured those endpoints. Any "expect changes in X weeks" figure is extrapolation from the hormone data or from self-report, not a measured outcome. That gap is why the only meaningful record is your own: peptides are usually started alongside other changes — new training, diet, more sleep — so an uncontrolled personal trial is easy to misread. If a clinician has judged this appropriate for you, the way to learn anything is to log it consistently: injection dates and sites, side effects, sleep, training load, and any bloodwork such as IGF-1. That is the case for structured tracking with any GH-axis compound, and part of understanding how these compounds fit a broader metabolic picture.

Frequently asked questions

Sources

Every claim above traces to peer-reviewed literature indexed on PubMed, or to the published positions of the FDA and WADA:

1. Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults — PubMed 16352683
2. Pulsatile secretion of growth hormone (GH) persists during continuous stimulation by CJC-1295, a long-acting GH-releasing hormone analog — PubMed 17018654
3. Identification of CJC-1295, a growth-hormone-releasing peptide — PubMed 21204297
4. The role of growth hormone secretagogues in the modern clinic — PubMed 32257855
5. Ipamorelin, the first selective growth hormone secretagogue — PubMed 9849822
6. Sermorelin: a review of its use in the diagnosis and treatment of children with growth hormone deficiency — PubMed 18031173
7. Once daily subcutaneous growth hormone-releasing hormone therapy in GH-deficient children — PubMed 8772599
8. Effects of tesamorelin in HIV-infected patients with abdominal fat accumulation — PubMed 20554713
9. Effect of tesamorelin on visceral fat and liver fat in HIV-infected patients — PubMed 25038357
10. Understanding peptide hormones: from precursor proteins to biological function — PubMed 40234176
11. Drug Development 101: A Primer — PubMed 32762387
12. Drug Trials (overview of clinical trial phases) — PubMed 31536202

Regulatory positions cited: WADA's Prohibited List class S2 (peptide hormones, growth factors and mimetics) and the FDA's human drug compounding program and its Pharmacy Compounding Advisory Committee record for CJC-1295.

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