CJC-1295 & Ipamorelin Research Guide 2026 — Molecular Profiles & Verification

CJC-1295 and ipamorelin are two of the most frequently co-referenced compounds in growth-hormone (GH) axis pharmacology research. They are studied together because they engage the somatotroph — the GH-secreting cell of the anterior pituitary — through two distinct and complementary receptor systems: CJC-1295 as a long-acting analog of growth hormone-releasing hormone (GHRH), and ipamorelin as a selective agonist of the growth hormone secretagogue receptor (GHS-R1a). For laboratories modeling pituitary signaling, this pairing has become a standard reference system for studying how two independent receptor inputs converge on a single secretory pathway.

This guide is written for qualified laboratory researchers sourcing CJC-1295 and ipamorelin as research compounds. It covers the molecular profile of each peptide, the receptor-level mechanism as described in the published literature, representative preclinical and in-vitro research data, real citations you can verify yourself, and how to evaluate the analytical documentation that should accompany peptides of this class.

For in-vitro and preclinical laboratory research use only. Not for human consumption. Not for veterinary use.

Section 1 — Molecular Profile

These are two structurally unrelated peptides that are studied as a pair. Their molecular profiles are best understood separately.

CJC-1295 (long-acting GHRH analog)

• Compound name: CJC-1295 (with DAC); the underlying 29-residue peptide is also known as Modified GRF(1-29)
• CAS number: 863288-34-0 (with DAC); 446036-97-1 (without DAC / Modified GRF 1-29)
• Molecular formula (without DAC): C₁₅₂H₂₅₂N₄₄O₄₂
• Molecular weight (without DAC): ≈ 3367.9 g/mol
• Class: Synthetic GHRH(1-29) analog
• Receptor target: GHRH receptor (GHRH-R, a class B GPCR)

CJC-1295 is a synthetic analog of the first 29 amino acids of human GHRH. It carries four amino-acid substitutions — D-Ala at position 2, Gln at position 8, Ala at position 15, and Leu at position 27 — that were selected to confer resistance to enzymatic cleavage by dipeptidyl peptidase-4 (DPP-4) and other plasma proteases. The “DAC” (drug affinity complex) version adds a maleimidopropionamide group at the C-terminal lysine. In the published characterization work, this maleimide reacts with the free thiol on cysteine-34 of circulating albumin to form a covalent thioether bond — the structural feature responsible for the compound’s markedly extended plasma stability profile. Because the DAC modification adds mass, published molecular-weight values differ between the with-DAC and without-DAC forms; the without-DAC 29-mer above is the reliable analytical anchor, and any COA should specify which form was tested.

Ipamorelin (selective GHS-R1a agonist)

• Compound name: Ipamorelin (NNC 26-0161)
• CAS number: 170851-70-4
• Molecular formula: C₃₈H₄₉N₉O₅
• Molecular weight: ≈ 711.85 g/mol
• Sequence: Aib-His-D-2-Nal-D-Phe-Lys-NH₂
• Class: Pentapeptide growth hormone secretagogue (GHRP)
• Receptor target: GHS-R1a (ghrelin receptor, a class A GPCR)

Ipamorelin is a synthetic pentapeptide derived from the growth hormone-releasing peptide (GHRP) series. Its small size and C-terminal amide, together with the non-natural residues Aib and D-2-Nal, define both its receptor selectivity and its analytical fingerprint. At roughly 712 g/mol it is a far smaller molecule than CJC-1295, which is why the two compounds require different chromatographic and mass-spectrometric method parameters even when supplied together.

Section 2 — Mechanism (Pathway Language)

The reason these two peptides are studied as a pair is that they are described in the literature as engaging the somatotroph through two separate receptor systems that act on complementary intracellular pathways.

CJC-1295 — the GHRH receptor pathway. CJC-1295 is studied as an agonist of the GHRH receptor, a class B (secretin-family) GPCR expressed on anterior-pituitary somatotrophs. In the published mechanistic literature, GHRH-R activation couples primarily to the stimulatory G protein (Gαs), activating adenylate cyclase and raising intracellular cyclic adenosine monophosphate (cAMP), with downstream engagement of protein kinase A (PKA). The four stabilizing substitutions and, in the DAC form, albumin conjugation are described as extending the duration over which this receptor is engaged in preclinical models.

Ipamorelin — the GHS-R1a pathway. Ipamorelin is studied as a selective agonist of GHS-R1a, the ghrelin receptor, a class A GPCR. In the published literature, GHS-R1a activation couples through Gαq/phospholipase C (PLC), generating inositol trisphosphate (IP₃) and mobilizing calcium from intracellular stores. A defining feature reported for ipamorelin is its selectivity: comparative studies describe GHS-R1a engagement without significant activation of the pathways that drive adrenocorticotropic hormone (ACTH), cortisol, or prolactin release, distinguishing it from earlier, less selective GHRPs.

The cAMP/PKA pathway (GHRH-R) and the PLC/calcium pathway (GHS-R1a) are described as complementary, which is why the two compounds are used together as a two-input model system in receptor-signaling research. In accordance with research-context framing, this article describes both compounds strictly at the receptor and second-messenger level. Each is studied for its interaction with its target receptor and the resulting signaling cascade; no human outcome, therapeutic, or physiological benefit is claimed or implied.

Section 3 — Preclinical & In-Vitro Research Data

The published literature for both compounds spans cell-line, primary-tissue, and animal-model systems.

GHRH-receptor characterization (CJC-1295). The foundational characterization work identified hGRF(1-29)-albumin bioconjugates that activate the GRF receptor on the rat anterior pituitary, establishing CJC-1295 as a long-lasting GRF analog. Follow-on preclinical work in a GHRH-knockout mouse model examined whether once-daily administration of the analog could restore GHRH-receptor signaling in animals lacking endogenous GHRH — a model system specifically designed to isolate GHRH-R pathway activity.

GHS-R1a selectivity characterization (ipamorelin). The landmark ipamorelin study characterized it as the first selective growth hormone secretagogue, using preclinical models to demonstrate GHS-R1a-mediated GH release with a selectivity profile distinct from that of other GHRPs. Subsequent rat-model work examined GHS-R pathway engagement using longitudinal bone-growth endpoints as a downstream readout of somatotroph-axis signaling.

In-vitro receptor cell-line systems. A useful methodological reference for GHS-R1a research is the establishment of a cell line stably expressing the growth hormone secretagogue receptor, used to screen and identify ghrelin-receptor agonists in vitro. Cell lines of this type are the standard platform for quantifying GHS-R1a agonist potency and are directly relevant to laboratories using ipamorelin as a reference ligand.

Across these studies, the common experimental thread is receptor engagement quantified through second-messenger and downstream signaling markers — cAMP for the GHRH-R pathway, calcium mobilization for the GHS-R1a pathway. None of this preclinical data constitutes evidence of any human outcome; it describes molecular and cellular behavior in controlled research systems only.

Section 4 — Published Literature (Verifiable Citations)

The following are real, published references retrievable through PubMed and PubMed Central (PMC). Researchers are encouraged to read the primary sources directly.

• Jetté 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;146(7):3052–3058 — the foundational CJC-1295 receptor-characterization paper.
• Alba M, et al. “Once-daily administration of CJC-1295, a long-acting GHRH analog, normalizes growth in the GHRH knockout mouse.” Am J Physiol Endocrinol Metab. 2006 — preclinical GHRH-R pathway study.
• Teichman 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.” J Clin Endocrinol Metab. 2006;91(3):799–805 — pharmacokinetic/pharmacodynamic characterization of the compound.
• Raun K, et al. “Ipamorelin, the first selective growth hormone secretagogue.” Eur J Endocrinol. 1998;139(5):552–561. PubMed: 9849822 — the landmark ipamorelin selectivity paper.
• Johansen PB, et al. “Ipamorelin, a new growth-hormone-releasing peptide, induces longitudinal bone growth in rats.” Growth Horm IGF Res. 1999 — preclinical GHS-R pathway study.
• “The growth hormone secretagogue receptor (Ghs-R).” PubMed: 22632856 — mechanistic review of GHS-R1a signaling and tissue distribution.
• “Establishment of a Cell Line Stably Expressing the Growth Hormone Secretagogue Receptor to Identify Crocin as a Ghrelin Agonist.” PubMed Central: PMC9775697 — in-vitro GHS-R1a cell-line screening method.

Citing real primary literature is a core part of the PYXAX research-context standard. Any source — vendor or publication — that references “studies” without traceable identifiers should be treated with caution.

Section 5 — Research Applications (In-Vitro Use Cases)

Within qualified laboratory settings, CJC-1295 and ipamorelin are used as reference compounds in several categories of in-vitro and preclinical work:

• Two-pathway pituitary signaling models — as complementary reference agonists for studying how the GHRH-R (cAMP/PKA) and GHS-R1a (PLC/calcium) inputs converge on the somatotroph.
• Receptor-specific functional assays — CJC-1295 as a GHRH-R reference agonist in cAMP-accumulation assays; ipamorelin as a GHS-R1a reference ligand in calcium-mobilization or IP₃ assays in receptor-expressing cell lines.
• Selectivity profiling — ipamorelin as a well-characterized selective comparator when profiling GHS-R1a agonists against ACTH/cortisol/prolactin pathway activity.
• Peptide stability and analytical method development — CJC-1295 (with DAC) as a model albumin-binding, DPP-4-resistant peptide, and ipamorelin as a model small non-natural pentapeptide, for developing and validating HPLC and LC-MS methods.

Each of these applications is an in-vitro or preclinical research use. Compounds supplied for research are not intended for, and must not be used in, any human or veterinary context.

Section 6 — How to Evaluate a Source

When two peptides are supplied together, documentation quality has to be confirmed for each one independently. The following steps separate verifiable sourcing from marketing claims.

Step 1 — Confirm the testing laboratory is named. “Third-party tested” is meaningless without a named, accredited laboratory. Look for an ISO 17025-accredited facility or equivalent recognized accreditation.

Step 2 — Confirm identity by mass spectrometry for each compound. CJC-1295 (≈3368 g/mol without DAC, higher with DAC) and ipamorelin (≈712 g/mol) are separated by roughly 2,600 daltons; a single COA must confirm the identity of each peptide at its own expected mass, not a blended average.

Step 3 — Verify which CJC-1295 form was tested. Because the with-DAC and without-DAC forms differ in mass and CAS number, the COA should state explicitly which form the analytical data corresponds to. Ambiguity here is a documentation red flag.

Step 4 — Verify lot specificity. The batch number on the COA must match the vial label, and the COA date should correspond to the production lot — not a single historical testing event applied across an entire catalog.

Step 5 — Check independent verification and a complete panel. A COA you can verify without contacting the vendor — through a QR-linked laboratory portal or a searchable community database — is independent. For cell-based research, purity and identity should be accompanied by endotoxin and heavy-metal data, both of which can confound sensitive assay systems.

Section 7 — PYXAX Verification Standard

PYXAX supplies CJC-1295 and ipamorelin as lyophilized research compounds independently verified by accredited independent laboratories (ISO 17025) before listing.

Testing panel:

• Chromatographic purity by HPLC
• Molecular identity by LC-MS
• Endotoxin (USP 85 LAL method)
• Heavy metals by ICP-MS
• QR-verified, batch-specific COA published for every lot

Lot-specific documentation. Every production lot receives its own batch number. The batch number on the vial matches the batch number on the COA in the PYXAX COA Library, so researchers can confirm identity before ordering.

Community verification. Select lots are submitted to Janoshik Analytical for community verification, with results publicly searchable by batch number — no vendor contact required.

Founding batch transparency. Initial founding batches were verified by Krause Analytical (accredited US laboratory). Ongoing production lots are tested across a network of accredited independent laboratories — including ILS Labs, Krause Analytical, and Janoshik — with a batch-specific COA published for every lot.

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All PYXAX compounds are supplied strictly for in-vitro and preclinical laboratory research use only. Not for human consumption. Not for veterinary use. Not for diagnostic procedures. These statements have not been evaluated by the FDA. Researchers are responsible for compliance with all applicable laws and regulations governing the use of research compounds in their jurisdiction.