CJC-1295 without DAC is more accurately called Modified GRF 1-29: a synthetic 29-residue GHRH analogue that keeps the receptor-binding core of growth hormone-releasing hormone but substitutes four residues — at positions 2, 8, 15 and 27 — to block the three chemical routes by which the native fragment falls apart. The name is a piece of market shorthand rather than chemistry. The original CJC-1295 described in the literature was the albumin-binding, drug-affinity-complex version; the peptide sold as CJC-1295 no DAC is the tetrasubstituted GRF 1-29 backbone without that conjugation, and it behaves completely differently.
This page sets out what each of the four substitutions does, how the peptide acts at the GHRH receptor, why laboratories choose the short-acting version, and how the material is handled and verified. CJC-1295 (No DAC) is supplied for laboratory research use only.
CJC-1295 (No DAC) at a glance
| Property | Value |
|---|---|
| Preferred name | Modified GRF 1-29 (Mod GRF 1-29) |
| Backbone | GHRH (1–29) amide |
| Substitutions | D-Ala at 2, Gln at 8, Ala at 15, Leu at 27 |
| Length | 29 residues, C-terminally amidated |
| CAS number | 863288-34-0 |
| Molecular formula | C152H252N44O42 |
| Molecular weight | 3367.93 g/mol |
| Receptor | GHRH receptor (GHRHR), class B GPCR |
| Signalling | Gs → adenylyl cyclase → cyclic AMP → protein kinase A |
| Albumin conjugation | None — short exposure, rapid clearance |
| Sizes supplied | 2 mg, 5 mg, 10 mg lyophilized vials |
| Purity specification | ≥99% by RP-HPLC with lot-matched COA |
Origin and structure: four substitutions, three problems
Native GHRH (1–29) amide — the peptide sold as sermorelin — has three well-documented liabilities, and Modified GRF 1-29 addresses each of them at a specific position.
Position 2: alanine to D-alanine. Dipeptidyl peptidase-4 cleaves after the residue at position 2, removing the first two amino acids and destroying activity, because the N-terminal region is what engages the transmembrane core of the receptor. Substituting the natural L-alanine for its D-enantiomer leaves the side chain unchanged but inverts the stereochemistry the protease requires. This single change accounts for most of the stability gain.
Position 8: asparagine to glutamine. Asparagine residues, particularly when followed by small residues, undergo spontaneous deamidation through a cyclic succinimide intermediate, converting the sequence into aspartate and isoaspartate forms during storage. Glutamine has an additional methylene group in its side chain and cannot form that intermediate readily, which removes the degradation route entirely.
Position 15: glycine to alanine. Glycine gives the backbone unusual conformational freedom. Replacing it with alanine constrains the local geometry, and the substitution has been reported to increase potency in structure-activity work.
Position 27: methionine to leucine. Methionine oxidises to the sulfoxide on exposure to air, generating the +16 Da satellite familiar from certificates for sermorelin. Leucine is a close steric match with no oxidisable sulfur. This is why the molecular formula for Modified GRF 1-29 contains no sulfur at all, unlike sermorelin.
Taken together the four changes convert a fragile research peptide into a chemically robust one while preserving the amidated C-terminus and the receptor-binding character of the parent sequence.
How it is thought to work
The mechanism is GHRH receptor agonism. Binding to the receptor on pituitary somatotrophs activates Gs, raises cyclic AMP and activates protein kinase A, increasing growth hormone gene transcription and release of stored hormone. Somatostatin tone and IGF-1 feedback remain intact, so the response stays within physiological regulation rather than overriding it.
What distinguishes this version from CJC-1295 with DAC is exposure time rather than mechanism. Without the maleimide linker that tethers the peptide covalently to serum albumin, clearance is rapid and the half-life is short — reported in the region of half an hour rather than days. In research terms this is a feature, not a shortcoming. A short exposure window produces a discrete pulse of receptor activation, which is what is required to study pulsatile GHRH signalling, receptor recovery and the natural rhythm of the somatotropic axis. Continuous occupancy, which the DAC version provides, answers a different question and carries the possibility of receptor desensitisation.
What research has examined
Structure-activity relationships
Modified GRF 1-29 is a standard comparator in work characterising GHRH receptor agonists, set against native GRF 1-29, sermorelin and longer analogues. Its value in that role comes from being chemically stable enough to give reproducible results without introducing the confound of prolonged exposure.
Pulsatile signalling and receptor pharmacology
Cell and animal studies of cyclic AMP accumulation, somatotroph responsiveness and secretion patterns use the short-acting analogue specifically to isolate discrete receptor activation events. Comparisons with the long-acting version are covered in CJC-1295 vs CJC-1295 with DAC, and with the unmodified fragment in CJC-1295 vs sermorelin.
Combination designs
The most common experimental pairing places a GHRH receptor agonist alongside a growth hormone secretagogue receptor agonist such as ipamorelin. The two receptors sit on the same cell and signal through different second messengers — cyclic AMP and phospholipase C respectively — and their combination has been reported as more than additive in some models. Pre-blended research material exists for this design as CJC-1295 with ipamorelin.
All of this work is preclinical and in vitro. Modified GRF 1-29 has no approved use anywhere, and there is no controlled human trial record for it.
Forms and sizes we supply
CJC-1295 (No DAC) is stocked as a lyophilized powder in 2 mg (USD 45), 5 mg (USD 80) and 10 mg (USD 130) sealed vials. At 3367.93 g/mol, a 5 mg vial contains approximately 1.48 micromoles — near-identical molar content to a 5 mg sermorelin vial, which makes the two convenient to compare directly on a molar basis. The family sits under GHRH analogs. The albumin-binding version is stocked separately as CJC-1295 with DAC.
Reconstitution and storage in a laboratory context
The calculation: a 5 mg vial reconstituted with 2 mL of bacteriostatic water gives 2.5 mg/mL, equivalently 2,500 mcg/mL; 0.1 mL (10 units on a U-100 syringe) contains 250 mcg. In molar terms that stock is approximately 742 micromolar, so an assay running at 10 nanomolar needs a dilution of about 74,000-fold, performed in stages.
This peptide is more forgiving than most in storage, and the reason is chemical rather than procedural: with no methionine and no deamidation-prone asparagine at position 8, two of the three common degradation routes have been engineered out. That does not make it indestructible — lyophilized vials still go to −20 °C protected from light and moisture, and reconstituted solution is still aliquoted and kept cold — but it does mean fewer degradation products on a certificate after storage. General guidance is in the peptide storage guide.
Purity, COA and how to read one
Each lot is purified by reversed-phase HPLC to at least 99% with mass confirmation and a lot-matched certificate. Three checks are specific to this peptide. First, the mass should match 3367.93 g/mol; unmodified GHRH (1–29) amide is 3357.93 g/mol, a 10 Da difference that separates Modified GRF 1-29 from plain sermorelin. Since the two are sometimes conflated in the market, this is the single most useful identity check available. Second, confirm no sulfur is reported in the molecular formula — the presence of methionine would indicate the unmodified sequence. Third, note that mass spectrometry cannot distinguish D-alanine from L-alanine at position 2, so the stereochemistry rests on synthesis records and supplier documentation rather than on the certificate itself; chiral analysis is a separate test. Our COA reading guide explains what each section of a certificate can and cannot establish.
Regulatory status
Neither Modified GRF 1-29 nor any product marketed as CJC-1295 has marketing authorisation as a medicine in the United States or elsewhere, and neither is a dietary supplement ingredient. Material supplied here is research use only, for in-vitro and preclinical laboratory investigation by qualified researchers, and is not intended for human or veterinary administration.
Related peptides and further reading
Sermorelin is the unmodified parent fragment, tesamorelin the acylated full-length analogue, and CJC-1295 with DAC the long-acting albumin-bound version — four answers to the same stability problem at the same receptor. On the secretagogue side, ipamorelin, GHRP-2 and GHRP-6 act at the ghrelin receptor instead, and the whole landscape is mapped in the GH secretagogue landscape explained.