CJC-1295 (no DAC)What the studies show
Sermorelin with four amino acids swapped to survive the blood longer, and without the albumin-binding tail that gave the DAC version its week-long half-life.
5 min read · Animal and lab studies · Updated November 2026
In short
- Name
- CJC-1295 without DAC (modified GRF 1-29) (sold by Progression Labs as CJC-1295 (no DAC))
- Evidence
- Animal and lab studies
- Bottom line
- Receptor and rat pharmacology published as part of the CJC-1295 development programme, plus human data that belong to the DAC form and to sermorelin; there is no trial of this exact peptide in people.
Before you read this
This guide explains what published studies found. That is all it is.
It is not medical advice and it is not instructions for using anything. Where a dose appears, we are reporting what a named study gave the people or animals in it — a fact about the study, not an instruction to you.
The compounds here are not approved by the FDA for use in people and are sold for laboratory research only. A study tells you what happened to the subjects in it; it does not tell you what would happen to you. Talk to a doctor first.
What it is
Modified GRF 1-29 is the first 29 amino acids of human growth hormone releasing hormone (GHRH) with four of them replaced. GRF 1-29 on its own is sermorelin, and it is the shortest piece of GHRH that still fully stimulates the pituitary to release growth hormone, a fact established when the hormone was first isolated from a pancreatic tumour in 1982 1. The four substitutions, at positions 2, 8, 15 and 27, are the ones a Montreal company called ConjuChem used as the base for CJC-1295 2. The name "CJC-1295 without DAC" means that base peptide without ConjuChem's albumin-binding tail, which is why the research literature does not use the name at all: it describes a tetrasubstituted GRF 1-29 analogue, and the papers about it are papers about CJC-1295.
The studies below call this molecule CJC-1295 without DAC (modified GRF 1-29). Progression Labs sells it as CJC-1295 (no DAC); the guide uses the store's name and the papers use theirs.
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Why each change was made
Natural GHRH is destroyed in blood within minutes. The main cut is made by an enzyme called dipeptidyl peptidase IV, which clips off the first two amino acids and leaves a fragment that no longer works; Frohman's group showed this in 1986 in both the test tube and living people, and measured the intact hormone's half-life in plasma in minutes 3. Putting a D-alanine at position 2 blocks that enzyme, which is the first substitution.
The other three address slow chemical damage rather than enzymes. The asparagine at position 8 tends to rearrange and lose activity, so it becomes glutamine. The glycine at position 15 becomes alanine, which stiffens the helix the receptor recognises. The methionine at position 27 oxidises easily in solution and becomes leucine 2. ConjuChem's 2005 paper in Endocrinology describes testing these substituted analogues, with and without the albumin tail, in rats, and reports that the substitutions preserved activity at the GHRH receptor on pituitary cells 2.
What the DAC version adds, and this one lacks
CJC-1295 proper has a thirtieth residue, a lysine carrying a reactive group that bonds permanently to albumin in the blood. ConjuChem called this the drug affinity complex, or DAC. Bonded to albumin, the peptide stays in circulation for days: in healthy adults the measured half-life was 5.8 to 8.1 days and growth hormone stayed raised for about a week after one injection 4. Without the tail, the four substitutions slow the breakdown of the peptide but do not stop the kidney clearing it, so the peptide is expected to act for minutes to an hour or so like sermorelin, not for days. That is the practical difference the two names point at: same receptor, same base sequence, very different duration.
What the studies found, and in what
Everything published on the growth-hormone effect of this sequence in people was measured on the DAC form. In those studies, the GHRH receptor pathway behaved as expected: growth hormone and IGF-1 rose, and the pituitary kept releasing growth hormone in its normal pulses rather than in a flat line 45. The nearest human evidence for the unmodified base is sermorelin itself, which was an approved prescription product in the United States for growth hormone deficiency in children and was studied in healthy older men, where it raised growth hormone and IGF-1 6.
The tetrasubstituted peptide on its own, without the tail, has no published clinical trial. The 2005 rat work is the only direct pharmacology of the unconjugated analogue, and it was done to pick a candidate, not to characterise the peptide for its own sake 2.
What is not known
No study has measured how long modified GRF 1-29 lasts in human blood, what growth hormone response it produces in people, or what happens with repeated dosing over weeks. Those answers are assumed from sermorelin and from CJC-1295 with DAC, and assumption is what they are. The peptide is not an approved drug anywhere, and neither is the DAC form it was derived from.
What these studies are, and aren't
Animal and lab studies. Receptor and rat pharmacology published as part of the CJC-1295 development programme, plus human data that belong to the DAC form and to sermorelin; there is no trial of this exact peptide in people.
Sources
- 1Rivier J, Spiess J, Thorner M, Vale W. Characterization of a growth hormone-releasing factor from a human pancreatic islet tumour. Nature, 1982.
- 2Jetté L et al. 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.
- 3Frohman LA et al. Rapid enzymatic degradation of growth hormone-releasing hormone by plasma in vitro and in vivo to a biologically inactive product cleaved at the NH2 terminus. Journal of Clinical Investigation, 1986.
- 4Teichman SL 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 & Metabolism, 2006.
- 5Ionescu 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 & Metabolism, 2006.
- 6Prakash A, Goa KL. Sermorelin: a review of its use in the diagnosis and treatment of children with idiopathic growth hormone deficiency. BioDrugs, 1999.
More in Growth hormone axis
- CJC-1295 + Ipamorelin: What the Studies ShowTwo peptides for two receptors on the same pituitary cell. The idea comes from a 1990 study in men; the pair itself has never been tested together.
- CJC-1295 with DAC: What the Studies ShowA GHRH analogue that bonds to albumin in the blood: one injection raised growth hormone for about a week in healthy adults, with the normal pulses intact.
- GHRP-2: What the Studies ShowThe potent GHRP approved in Japan as a one-dose test for growth hormone deficiency, and shown to make healthy men eat about a third more at a single meal.
- GHRP-6: What the Studies ShowThe 1984 hexapeptide that came before its own receptor and before ghrelin — and the reason the hunger it causes is the receptor doing its job.
- Hexarelin: What the Studies ShowGHRP-6 with one methyl group added, active by mouth and nose as well as by injection, and the GHRP whose growth hormone response was shown to fade by 16 weeks.