Molecule guides
CJC-1295 + Ipamorelin: Two Receptors, One Somatotroph, and the Arithmetic of a Blend
A co-lyophilized GHRH analogue and selective ghrelin-receptor agonist: the pathway logic, the fixed molar ratio it locks in, and how to read its COA.
The CJC-1295 + Ipamorelin blend places two peptides in one vial that target different receptors within the same axis: CJC-1295 (No DAC), a hardened 29-residue GHRH analogue acting at the GHRH receptor of pituitary somatotrophs, and ipamorelin, a selective pentapeptide agonist of the ghrelin receptor GHS-R1a. Pairing them makes sense because each receptor feeds a separate signalling route inside the same cell, Gs/cAMP in the case of the GHRH receptor and Gq/phospholipase C for GHS-R1a, and published pituitary pharmacology reports that exposure to a GHRH analogue plus a secretagogue yields a bigger secretory response than either molecule on its own.
Peptide Medix EU supplies CJC-1295 (No DAC) + Ipamorelin co-lyophilized at 1:1 in 10 mg (5 mg/5 mg) and 20 mg (10 mg/10 mg) vials within the growth hormone blends range.
The two components
CJC-1295 (No DAC) also appears as Mod GRF (1-29). It consists of the opening 29 residues of human GHRH, the smallest fragment that keeps full receptor activity, with four engineered substitutions aimed at specific decay routes: D-alanine at 2 to defeat dipeptidyl peptidase-4, glutamine at 8 to delete an asparagine deamidation site, alanine at 15 to firm up the helix, and leucine at 27 to remove an oxidisable methionine. Calling it "No DAC" marks it out from the form carrying the drug affinity complex linker that latches onto serum albumin; without the linker the peptide is deliberately short-acting. Our explainer on what CJC-1295 is gives the full account.
Ipamorelin is a synthetic pentapeptide that came out of Novo Nordisk in the 1990s, built around aminoisobutyric acid and D-2-naphthylalanine residues that supply both stability and receptor affinity. Selectivity is its published hallmark: whereas the earlier GHRP compounds raised cortisol, ACTH and prolactin alongside growth hormone, animal and human pharmacology reported growth hormone release from ipamorelin without those concurrent increases seen with GHRP-2, GHRP-6 and hexarelin. Our ipamorelin explainer covers its structure.
Why the combination is used
The logic is complementary pathways in a single cell type. The GHRH receptor couples to Gs, so agonism raises cAMP and activates protein kinase A, which in the published model both triggers secretion and sustains somatotroph transcription. The ghrelin receptor couples to Gq, so agonism activates phospholipase C, generates inositol trisphosphate and raises intracellular calcium. Since the two reach secretion by different second messengers, pituitary preparations and human pharmacology studies of GHRH plus a secretagogue report a combined response exceeding the sum of the separate ones, and that observation is the origin of this whole blend category.
A further reported element is functional opposition to somatostatin, the axis's inhibitory arm. Ligands at GHS-R1a have been described as reducing somatostatin tone, which would allow a fuller GHRH-driven response. Both mechanisms are pituitary-level pharmacology and neither describes any outcome.
Two cautions belong in any protocol. GHS-R1a desensitises under continuous exposure, so the size of a combined response depends on how exposure is structured in time. And a 1:1 co-lyophilized blend pins the molar ratio at about 4.7 parts ipamorelin for every part of CJC-1295, because the molecular weights differ by nearly fivefold and equal mass is nothing like equal moles. Studies that need to vary that ratio must buy single-component vials, a point developed in our guide to peptide blends versus single vials.
Research to date
Combined GHRH and secretagogue pharmacology
The firmest evidence concerns the underlying principle rather than this particular commercial pairing. From the 1990s onward, human and animal studies gave GHRH together with a GHRP-class secretagogue and reported more growth hormone release than either produced alone, which is the synergy blend products are founded on.
Ipamorelin selectivity data
Preclinical studies at Novo Nordisk set ipamorelin against GHRP-6 and other secretagogues and reported similar growth hormone release without the accompanying ACTH and cortisol rise. That selectivity explains why modern blends use ipamorelin rather than an older GHRP.
Stability work on the GHRH analogue
A separate literature examined each of the four Mod GRF (1-29) substitutions against the degradation route it was designed to block, and compared DAC and non-DAC versions for persistence. The difference is meaningful: a short-acting analogue enables pulse-structured designs, while the albumin-binding version yields continuous exposure.
What has not been shown
No controlled studies exist of this specific co-formulation, and nothing published indicates that a fixed 1:1 mass ratio is optimal for any research question. On this catalogue as on every other, blend composition is a formulation convention rather than an evidence-based specification. The wider class is described in the GH secretagogue landscape explained.
Formats and sizes
Both sizes come co-lyophilized in one vial, so a single reconstitution yields a solution holding both peptides at the stated ratio. The 10 mg (5 mg/5 mg) vial fits shorter experimental series, while the 20 mg (10 mg/10 mg) vial is the better value when a longer study should stay on one lot. Every lot carries a certificate giving purity for each component individually at ≥99% by HPLC. Ordering points appear in our CJC-1295 + Ipamorelin buying guide, and the components are sold separately as CJC-1295 (No DAC) and Ipamorelin.
Reconstitution and storage in the lab
Treat the blend as one material during reconstitution. Choose bacteriostatic water when the vial will be entered repeatedly and sterile water when a preservative would disturb the assay. Add solvent down the vial wall and swirl instead of shaking.
Unless stated otherwise, the stated mass is total peptide. Reconstituting a 10 mg (5/5) vial with 2 mL of diluent produces 5 mg/mL overall, which means 2.5 mg/mL of each peptide, so 0.1 mL — the 10-unit graduation on a U-100 syringe — carries 250 mcg of CJC-1295 plus 250 mcg of ipamorelin. A 20 mg (10/10) vial in 4 mL gives identical per-volume numbers. Calculating from the total instead of the per-component figure is the classic blend arithmetic mistake; the full method sits in our reconstitution guide.
Keep sealed vials at −20 °C away from light and moisture, hold reconstituted solution at 2-8 °C for the study period, and aliquot and freeze for longer projects. The essentials are summarised in how to store peptides.
Reading a blend certificate
A certificate for a blend must settle a question a single-peptide certificate never raises: exactly what the vial holds and in what proportion. Check three things. Purity should be reported for each component separately rather than as one merged number. Mass spectrometry should display both expected masses, 3,367.93 g/mol and 711.85 g/mol, which together establish identity far more convincingly than either alone. And the ratio should be readable from the HPLC trace, where the two peptides resolve into separate peaks whose relative areas mirror the blend proportion. One purity value and one mass for a two-peptide product means the certificate is incomplete.
Regulatory position
Neither component is authorised as a medicine in the EU or the United States, and the blend holds no authorisation either. Growth hormone itself is a prescription biologic; these are secretagogues studied for their effect on its release and are not equivalent to it. Anti-doping rules prohibit growth hormone secretagogues and GHRH analogues in sport.
Related blends and further reading
The nearest alternatives keep the same secretagogue but change the GHRH-side partner: Tesamorelin + Ipamorelin uses a stabilised full-length 44-residue analogue, while Sermorelin + Ipamorelin uses the unmodified native GHRH (1-29) fragment.
Questions
What is the point of putting CJC-1295 and ipamorelin in one vial?
They engage different receptors on the same pituitary cell. The GHRH receptor is Gs-coupled and raises cAMP, while GHS-R1a is Gq-coupled and raises intracellular calcium. Published pharmacology describes a larger combined secretory response when a GHRH analogue and a secretagogue are given together than with either separately.
Does a 1:1 blend contain equal moles of each peptide?
It does not. The molecular weights differ nearly fivefold, 3,367.93 g/mol against 711.85 g/mol, so equal masses mean roughly 4.7 moles of ipamorelin per mole of CJC-1295. Molar comparisons must be worked out from the individual weights rather than taken from the vial label.
What is meant by "No DAC"?
It marks the version lacking the drug affinity complex linker that binds serum albumin. Without that linker the peptide is intentionally short-acting, which suits pulse-structured designs, whereas the DAC version gives continuous exposure. The same molecule is also catalogued as Mod GRF (1-29).
Why ipamorelin instead of an older GHRP?
Because of its selectivity. Preclinical data reported growth hormone release on a par with GHRP-6 but without the simultaneous ACTH and cortisol response that the older secretagogues produce. That cleaner profile is why current blends favour it.
How do you calculate concentrations for a blend?
Use the per-component figure rather than the total. A 10 mg (5/5) vial reconstituted with 2 mL yields 5 mg/mL overall, which is 2.5 mg/mL of each peptide, so 0.1 mL holds 250 mcg of each. Treating the total mass as if it were a single peptide is the commonest arithmetic error with blends.
What belongs on a blend certificate of analysis?
Purity given per component instead of one combined value, mass spectrometry showing both expected masses (3,367.93 and 711.85 g/mol), and an HPLC trace whose two well-separated peaks allow the ratio to be checked. A single purity figure and one mass for a two-component product leaves the certificate incomplete.
Has this specific blend been studied in controlled research?
No. The evidence covers the general principle of pairing a GHRH analogue with a secretagogue, plus each component individually. Nothing published shows that a fixed 1:1 mass ratio is ideal for any research question, since blend composition is simply a formulation convention.