CJC-1295 DAC vs no DAC: what the names actually mean

Research-use notice: this article is for legitimate laboratory and educational research only. It does not provide guidance for human use, administration, dosing or treatment.

CJC-1295 is a synthetic analogue of growth hormone-releasing hormone (GHRH): the 29-amino-acid fragment GRF(1–29) with four amino-acid substitutions, plus an extra lysine that carries a drug affinity complex (DAC). The DAC is a maleimide-based group that binds covalently to albumin in the blood, and human trials published in 2006 estimated a half-life of 5.8–8.1 days. “CJC-1295 no DAC” is often used for a related 29-residue peptide, modified GRF(1–29), which the published CJC-1295 trials did not study. Neither is a licensed medicine in the UK, and GHRH analogues are prohibited in sport.

What is CJC-1295?

CJC-1295 was described in 2005 by Jetté and colleagues in Endocrinology. Their starting point was human growth hormone-releasing factor 1–29, hGRF(1–29), the first 29 amino acids of GHRH. They made three maleimide-bearing derivatives and bound them to human serum albumin outside the body. All three conjugates resisted the enzyme dipeptidyl peptidase-IV in vitro and stimulated growth hormone (GH) secretion from cultured rat pituitary cells.

The analogue they selected, CJC-1295, is a tetrasubstituted form of hGRF(1–29) with:

• D-alanine at position 2
• glutamine at position 8
• alanine at position 15
• leucine at position 27
• an added lysine at the C-terminus, carrying a maleimidopropionamide group

In rats, CJC-1295 produced a fourfold increase in GH area under the curve over 2 hours compared with hGRF(1–29), was still present in plasma beyond 72 hours, and appeared bound to serum albumin. The authors identified it as a stable, active analogue with an extended plasma half-life. Doping-control papers by Timms and colleagues describe CJC-1295 as a 30-amino-acid peptide whose four substitutions confer protease resistance.

What does DAC mean?

DAC stands for drug affinity complex. In CJC-1295 it is the maleimidopropionic acid group on the extra lysine, which Timms and colleagues note is “sometimes called the drug affinity complex (DAC)”.

The chemistry is specific. A maleimide reacts with a free thiol, and serum albumin has a single unpaired cysteine, at position 34. The 2006 human trial paper by Teichman and colleagues describes the maleimidopropionic acid binding covalently to that cysteine. Jetté and colleagues described the approach as in vivo bioconjugation to the free thiol on cysteine 34 of serum albumin, and identified CJC-1295 as an analogue with an extended plasma half-life. Timms and colleagues add that the group can bind other plasma proteins too, which is one reason conjugated CJC-1295 is hard to detect in blood.

The effect on persistence is large. In a related screening paper, Timms and colleagues list a half-life of 7 minutes for human GHRH. Teichman and colleagues estimated a half-life of 5.8–8.1 days for CJC-1295 in healthy adults.

CJC-1295 DAC vs no DAC: what is the difference?

The answer depends on what a label means, because three related molecules circulate under similar names. A 2019 doping-control paper by Timms and colleagues lists them as separate sequences with different masses, given as MH+ (the monoisotopic mass of the singly protonated molecule):

The same table lists half-lives of 6–8 days for CJC-1295, under 10 minutes for CJC-1295 minus DAC and 30 minutes for modified GRF(1–29). The 2005 study’s comparator, hGRF(1–29), is the unsubstituted parent fragment.

In the research-peptide market, “CJC-1295 no DAC” is often used for modified GRF(1–29), also called “mod GRF 1-29”. Strictly, that is not CJC-1295 with the DAC removed, because it also lacks the 30th residue, the lysine. The confusion is not only commercial. A 2010 paper from the Norwegian doping-control laboratory described an unknown preparation submitted by Norwegian authorities that contained a 29-amino-acid peptide with a C-terminal amide, whose proposed sequence the authors judged consistent with a peptide marketed as CJC-1295. A 2021 study of detection methods likewise listed “CJC-1295” and “CJC-1295 with drug affinity complex” as separate analytes.

Why naming matters

• Evidence does not transfer. The human data on CJC-1295 come from the DAC form. Findings on one form say nothing direct about another, and the listed half-lives differ by orders of magnitude.
• Identity is testable. The three forms differ by a lysine residue and a maleimide group, differences that mass spectrometry can resolve. A batch report should state which molecule it confirms.
• Study design changes. The DAC form is built to react with free thiols, and Jetté and colleagues prepared their albumin conjugates outside the body. In media containing serum albumin or other thiol-bearing components, the DAC form may be partly bound before it reaches its target, so controls need to match.

What the published research covers

The CJC-1295 literature is small. The main studies, with their evidence levels:

• Animal and cell studies (2005). Jetté and colleagues, cultured rat pituitary cells and rats: albumin conjugates of GRF(1–29) analogues stimulated GH secretion, and CJC-1295 was selected for its extended plasma half-life.
• Human trials (2006). Teichman and colleagues, Journal of Clinical Endocrinology and Metabolism: two randomised, placebo-controlled, double-blind trials lasting 28 and 49 days in healthy adults aged 21–61. At several dose levels, a single administration was followed by increases in mean plasma GH of 2- to 10-fold for 6 days or more, and in mean insulin-like growth factor I (IGF-I) of 1.5- to 3-fold for 9–11 days.
• Human physiology study (2006). Ionescu and Frohman sampled GH every 20 minutes over a 12-hour night in healthy men aged 20–40, before and one week after a single administration at one of two dose levels. The frequency and size of GH pulses were unchanged, while trough GH rose 7.5-fold, mean GH by 46% and IGF-I by 45%.
• Analytical chemistry (2010–2021). Doping-control papers describe how CJC-1295 and related GHRH analogues are identified in seized products and detected in urine and equine plasma.

These are early-phase studies of GH and IGF-I levels in healthy volunteers. They measured hormone levels, not clinical outcomes, and they studied one defined molecule. They are not evidence about any other material sold under a similar name.

Where does ipamorelin fit?

Ipamorelin acts through a different receptor. It is a growth hormone secretagogue (GHS): a pentapeptide, Aib-His-D-2-Nal-D-Phe-Lys-NH2, that Raun and colleagues described in 1998 in the European Journal of Endocrinology as “the first selective growth hormone secretagogue”. In rat pituitary cells, anaesthetised rats and conscious swine, they reported that ipamorelin released GH with a potency and efficacy similar to growth hormone-releasing peptide-6 (GHRP-6), and that, like GHRP-6, it acted through a GHRP-like receptor. In swine, it did not raise adrenocorticotropic hormone (ACTH) or cortisol to levels significantly different from those seen after GHRH stimulation.

Ipamorelin has also been tested in people for an unrelated purpose. A 2014 proof-of-concept, multicentre, double-blind, placebo-controlled trial in patients undergoing bowel resection examined it as a ghrelin-receptor agonist for postoperative ileus. Of 117 patients enrolled, 114 were analysed, and the authors found no significant differences between ipamorelin and placebo in the key and secondary efficacy analyses.

GHRH analogues act on the GHRH receptor, while GH secretagogues act on a separate receptor, described by Raun and colleagues as GHRP-like and by later authors as the ghrelin receptor. That is why the two classes are often discussed together. As of October 2026, we are not aware of any peer-reviewed study of modified GRF(1–29) and ipamorelin as a combined, single-vial preparation.

How to check a CJC-1295 batch

With three similar molecules in circulation, the name on the label matters less than what the batch report confirms. Check:

• Which molecule is claimed. The report should name the sequence, not only “CJC-1295”: 29 residues (modified GRF(1–29)), 30 residues, or 30 residues with the DAC.
• Identity by mass spectrometry. The observed mass should match the stated structure, using values like those in the table above. A high-performance liquid chromatography (HPLC) purity figure cannot confirm this on its own; our article on HPLC vs mass spectrometry explains why.
• Related sequences. A missing or extra residue changes the molecule. See peptide sequence impurities for how deletion and truncation products show up.
• Each component of a blend. A CJC-1295 and ipamorelin blend needs two identity confirmations, not one for the vial as a whole.
• The batch number, method and date, along with the laboratory’s report reference.

Our guide on how to read a peptide COA covers the general method, our supplier traceability checklist lists the questions to ask, and you can look up any Thistle batch on our batch report lookup. For the DAC form, record buffer and media composition, since thiol-containing reagents may react with the maleimide group.

Thistle supplies CJC-1295 DAC — 5mg Research Peptide at £34.99 and CJC-1295 no DAC — 5mg Research Peptide at £24.99, each with a batch laboratory report.

Is CJC-1295 legal in the UK?

CJC-1295 is not a licensed medicine in the UK, and neither is ipamorelin. Searches of the electronic medicines compendium (eMC), which publishes information on UK licensed medicines, returned no matches for either name, and we are not aware of any UK marketing authorisation for them.

Presentation matters. Under the Human Medicines Regulations 2012, a substance presented as having properties of preventing or treating disease in people is a medicinal product, as is one that may be used by or administered to people with a view to restoring, correcting or modifying a physiological function. In April 2026 the Medicines and Healthcare products Regulatory Agency (MHRA) said that if clinics make medicinal claims for peptide treatments, the products will be considered medicines under those Regulations.

Sport is explicit. The World Anti-Doping Agency (WADA) 2026 Prohibited List, in force from 1 January 2026, places growth hormone releasing factors under S2 (peptide hormones, growth factors, related substances and mimetics), which is prohibited at all times, in and out of competition. The entry names “growth hormone-releasing hormone (GHRH) and its analogues (e.g. CJC-1293, CJC-1295, sermorelin and tesamorelin)” and lists growth hormone secretagogues and their mimetics, naming ipamorelin. The category is introduced with the words “including, but not limited to”, so the named examples are not a complete list.

This section is general information, not legal advice.

CJC-1295 FAQs

What is the difference between CJC-1295 with and without DAC?

CJC-1295 with DAC carries a maleimide group on an extra lysine that binds albumin, which gave a half-life of several days in early trials. Products sold as “no DAC” often contain modified GRF(1–29), a 29-residue peptide without that group or the lysine.

Is CJC-1295 no DAC the same as mod GRF 1-29?

In commercial use, often yes. Strictly, modified GRF(1–29) has 29 residues, while CJC-1295 without its DAC would keep a 30th residue, lysine. Check the sequence and mass on the batch report.

Is CJC-1295 banned in sport?

Yes. CJC-1295 is named on the WADA 2026 Prohibited List under S2, and ipamorelin is named as a growth hormone secretagogue. Both are prohibited at all times.

Does CJC-1295 have side effects?

Published human data are limited to early-phase studies of the original CJC-1295 with DAC in healthy adults, and those data do not apply to research material. CJC-1295 is not for human use, and we cannot advise on personal use.

How much does CJC-1295 cost in the UK?

Prices vary by supplier and form. At the time of writing, Thistle sells CJC-1295 no DAC 5mg at £24.99. Price says nothing about content or purity, so check the batch report.

Sources

• Jetté L, Léger R, Thibaudeau K, et al. Human Growth Hormone-Releasing Factor (hGRF)1–29-Albumin Bioconjugates Activate the GRF Receptor on the Anterior Pituitary in Rats: Identification of CJC-1295 as a Long-Lasting GRF Analog. Endocrinology. 2005;146(7):3052–3058. Rat pituitary cells and rats.
• Teichman SL, Neale A, Lawrence B, et al. 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. Journal of Clinical Endocrinology and Metabolism. 2006;91(3):799–805. Randomised, placebo-controlled human trials.
• Ionescu M, Frohman LA. Pulsatile Secretion of Growth Hormone (GH) Persists during Continuous Stimulation by CJC-1295, a Long-Acting GH-Releasing Hormone Analog. Journal of Clinical Endocrinology and Metabolism. 2006;91(12):4792–4797. Human physiology study.
• Timms M, Ganio KE, Steel R. A method for confirming CJC-1295 abuse in equine plasma samples by LC–MS/MS. Drug Testing and Analysis. 2019;11(8):1248–1257. Analytical chemistry; equine plasma.
• Timms M, Ganio K, Forbes G, et al. An immuno polymerase chain reaction screen for the detection of CJC-1295 and other growth-hormone-releasing hormone analogs in equine plasma. Drug Testing and Analysis. 2019;11(6):804–812. Analytical chemistry; equine plasma.
• Henninge J, Pepaj M, Hullstein IR, et al. Identification of CJC-1295, a growth-hormone-releasing peptide, in an unknown pharmaceutical preparation. Drug Testing and Analysis. 2010;2(11-12):647–650. Analytical chemistry.
• Memdouh S, Gavrilović I, Ng K, et al. Advances in the detection of growth hormone releasing hormone synthetic analogs. Drug Testing and Analysis. 2021;13(11-12):1871–1887. Analytical chemistry; in vitro metabolism.
• Raun K, Hansen B, Johansen N, et al. Ipamorelin, the first selective growth hormone secretagogue. European Journal of Endocrinology. 1998;139(5):552–561. Rat pituitary cells, rats and swine.
• Beck DE, Sweeney WB, McCarter MD; Ipamorelin 201 Study Group. Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients. International Journal of Colorectal Disease. 2014;29(12):1527–1534. Proof-of-concept human trial.
• World Anti-Doping Agency. Prohibited List 2026. S2 peptide hormones, growth factors, related substances and mimetics; growth hormone releasing factors.
• The Human Medicines Regulations 2012, regulation 2. legislation.gov.uk. Definition of a medicinal product.
• Electronic medicines compendium (eMC). Product search. Searches for “CJC-1295” and “ipamorelin” returned no matches, 3 October 2026.
• Aesthetics Journal. MHRA investigates clinics following peptide claims. 15 April 2026.

Published by Thistle BioLabs, a UK supplier of research materials. This article summarises external research, not studies conducted by Thistle. Educational information only; no medical advice or recommendation for personal use.