CJC-1295 DAC vs No DAC: Half-Life and Research (2026)

CJC-1295 DAC vs No DAC: Half-Life, Structure and What the Research Shows

By Medical Team of Generic Peptides

Quick answer. CJC-1295 DAC vs No DAC is a comparison of two related but different molecules. CJC-1295 with DAC carries a chemical linker that binds it to albumin in the blood, which extended its half-life to roughly 6–8 days in healthy adults. "CJC-1295 No DAC" is a market name for Modified GRF (1-29), a shorter-acting analog without that linker. The DAC version has a small set of published human studies from 2005–2006. The No DAC version has almost none. Neither is approved as a drug, and both are prohibited in sport.

What Is CJC-1295? DAC and No DAC Explained

Both molecules start from the same template: the first 29 amino acids of growth hormone–releasing hormone (GHRH), the hypothalamic signal that tells the pituitary to release growth hormone (GH). That 29-residue fragment, GRF(1-29), carries the full biological activity of the native hormone. Its weakness is speed: enzymes in the blood, chiefly dipeptidyl peptidase-4 (DPP-IV), cut it at position 2 within minutes [5].

CJC-1295 No DAC Is Mod GRF 1-29

Modified GRF (1-29) is GRF(1-29) with four amino acid substitutions: D-alanine at position 2, glutamine at 8, alanine at 15 and leucine at 27 [1, 9]. Earlier research on GRF analogs showed that changing position 2 protects the peptide from DPP-IV cleavage, and that an alanine at position 15 further improves stability and activity [5]. The result is a more durable GHRH analog, but still a short-acting one.

The name "CJC-1295 No DAC" is a source of confusion. In the original research, CJC-1295 referred specifically to the version with the albumin-binding group [1]. The "No DAC" label was applied later, mainly by suppliers. We cover this molecule in detail in our Mod GRF 1-29 research guide.

What "DAC" Means: The Albumin Link

CJC-1295 with DAC is the same tetrasubstituted GRF(1-29), plus a lysine at the end carrying a maleimidopropionyl group [1]. DAC stands for Drug Affinity Complex, the developer's term for this technology. After injection in animal studies, the maleimide group reacted with a free thiol on cysteine-34 of serum albumin, forming a stable covalent bond [1].

Albumin is the most abundant protein in blood and stays in circulation for weeks. By riding on albumin, CJC-1295 DAC avoids rapid kidney clearance and enzyme breakdown. In the 2005 rat study that identified it, CJC-1295 was still detectable in plasma beyond 72 hours, and it produced a fourfold larger GH response over two hours than unmodified GRF(1-29) [1].

CJC-1295 DAC vs No DAC at a Glance

Molecular data: PubChem (CID 91971820 for CJC-1295; CID 56841945 for Mod GRF 1-29).

CJC-1295 With DAC: What Human Studies Measured

Almost all human data on CJC-1295 with DAC come from the developer, ConjuChem, and its academic collaborators in 2005–2006.

Single and repeated doses in healthy adults (2006). Two randomized, placebo-controlled, double-blind trials enrolled healthy adults aged 21–61 and followed them for 28 and 49 days [2]. A single administration produced:

• a dose-dependent rise in mean GH of 2- to 10-fold, lasting 6 days or more;
• a rise in mean IGF-1 of 1.5- to 3-fold, lasting 9–11 days;
• an estimated half-life of 5.8–8.1 days.

After repeated administration, mean IGF-1 stayed above baseline for up to 28 days. No serious adverse reactions were reported [2].

GH pulsatility (2006). A second study sampled GH every 20 minutes overnight in healthy men aged 20–40, before and one week after a single injection [3]. The frequency and size of GH pulses did not change. What changed was the floor: trough GH levels rose 7.5-fold, mean GH rose 46%, and IGF-1 rose 45%.

Growth in GHRH-deficient mice (2006). In mice lacking their own GHRH, CJC-1295 given every 24 hours for five weeks normalized body weight and length. Longer intervals improved growth without fully normalizing it, and the treated mice showed signs of somatotroph (GH-producing cell) proliferation [4].

These studies measured hormone levels and pharmacokinetics. None measured muscle mass, fat loss, strength or other clinical outcomes in humans. The published trials gave no approved or validated human dose, and none exists today.

CJC-1295 Without DAC: Why So Little Is Known

For a molecule so widely sold, CJC-1295 No DAC has a remarkably thin evidence base. A 2026 review in Frontiers in Endocrinology found no peer-reviewed human clinical study reporting its half-life and concluded that "CJC-1295 without DAC" "remains essentially uncharacterised in the peer-reviewed human literature" [8].

The short half-life figures often quoted online for Mod GRF 1-29 are extrapolations, not published measurements. What can be said is structural: without the albumin link, it should be cleared far faster than the DAC form, and its stabilizing substitutions should make it more durable than native GRF(1-29) [5].

Pulsatile vs Sustained GH Release

One of the most common questions about CJC-1295 DAC vs No DAC is whether the long-acting form flattens the body's natural GH rhythm. GH is normally released in bursts, mostly during sleep. Researchers worried that a GHRH signal lasting a week might replace those bursts with a constant output.

The 2006 pulsatility study found otherwise. Pulses continued at the same frequency and size, while the baseline between them rose [3]. Interestingly, the IGF-1 increase did not correlate with any measure of GH secretion in that study.

For Mod GRF 1-29, the theoretical argument is that a short-acting GHRH signal produces a brief GH pulse that more closely resembles natural secretion. That idea is widely repeated, but we found no human study that tested it directly.

Mod GRF 1-29 vs CJC-1295 vs Sermorelin

All three are GHRH analogs, and they are easy to mix up.

For the regulatory and research background on each, see our guides to sermorelin and tesamorelin. Researchers often study GHRH analogs alongside ghrelin-receptor agonists such as ipamorelin; our article on the CJC-1295 and ipamorelin blend covers that pairing.

Safety Findings From Studies

The published human studies were short and involved small groups of healthy volunteers, so they say little about long-term safety [2, 3].

The halted Phase 2 trial. ConjuChem began a 12-week Phase 2 trial of CJC-1295 in people with HIV-associated visceral obesity in 2005 [6]. In July 2006, the company stopped the study after a participant died [7]. The cause and any relationship to the drug were not established in public reports, and the trial is listed as terminated. CJC-1295 did not return to clinical development.

FDA's review. In its 2024 briefing for the Pharmacy Compounding Advisory Committee, the FDA reviewed CJC-1295 and its DAC forms for use in growth hormone deficiency and concluded that the evidence weighed against adding them to the list of substances pharmacies may compound [10, 11]. The committee then voted against listing every form, 13 to 0 for CJC-1295 with DAC [11]. The FDA's main stated concern is immunogenicity: the risk that the peptide, its impurities or aggregates trigger an immune response, particularly when injected [12]. Animal studies reviewed by the FDA also found dose-dependent injection-site irritation in dogs.

CJC-1295 DAC and No DAC: FDA and WADA Status

Checked October 23, 2026.

FDA. Neither CJC-1295 with DAC nor Mod GRF 1-29 is FDA-approved for any use. CJC-1295 was previously placed in Category 2 of the FDA's interim compounding policies. As of April 2026, the FDA lists it among substances whose nominations were withdrawn, with the note that compounded drugs containing CJC-1295 "may pose risk for immunogenicity for certain routes of administration" [12]. It was not on the agenda of the July 2026 advisory committee meeting. For the latest developments, see our report on the FDA's interim access policy for peptides.

WADA. The 2026 Prohibited List names CJC-1295 under S2.2.4, "Growth hormone-releasing factors," alongside sermorelin and tesamorelin, as GHRH analogues [13]. Mod GRF 1-29 falls under the same category as a GHRH analog. These substances are prohibited at all times.

How to Tell CJC-1295 DAC From No DAC on a COA

Because vials are sometimes labeled only "CJC-1295," the certificate of analysis is the most reliable way to know which molecule you have. The two differ by about 279 daltons, a gap that mass spectrometry resolves easily:

• CJC-1295 with DAC: expected molecular weight about 3,647 Da.
• Mod GRF 1-29 (No DAC): expected molecular weight about 3,368 Da.

A useful COA should show a mass spectrum or measured mass matching one of these values, HPLC purity, and a lot number that matches the vial. A COA that reports only purity cannot tell you which form is inside. Our guide on how to read a research peptide COA walks through each section.

Generic Peptides supplies both forms for laboratory research, each with a lot-specific COA: CJC-1295 DAC and Mod GRF 1-29. Both are listed in our Growth Hormone & IGF-1 category.

FAQ

What is the difference between CJC-1295 DAC and No DAC?

CJC-1295 with DAC has a linker that binds it to albumin, extending its half-life in humans to roughly 6–8 days. CJC-1295 No DAC (Mod GRF 1-29) lacks that linker and acts for a much shorter time.

Is CJC-1295 No DAC the same as Mod GRF 1-29?

Yes. "CJC-1295 No DAC" is a market name for Modified GRF (1-29). In the original research literature, the name CJC-1295 referred to the DAC version.

What is the half-life of CJC-1295 with DAC?

In healthy adults, the estimated half-life was 5.8–8.1 days, and IGF-1 remained elevated for 9–11 days after a single administration.

Does CJC-1295 with DAC stop natural GH pulses?

In a 2006 study of healthy men, GH pulses continued at the same frequency and size; the baseline GH level between pulses rose 7.5-fold.

Is CJC-1295 FDA-approved or legal in sport?

Neither form is FDA-approved. Both are prohibited at all times under WADA category S2.2.4 as GHRH analogues.

References

For research use only. Not for human consumption. This content is for informational purposes and is not medical advice.