CJC-1295 and ipamorelin: the two molecules in the blend, the receptors they act on, and what has and has not been studied

What is in a CJC-1295 ipamorelin vial#

The Renuvia vial contains 5 mg of CJC-1295 without DAC and 5 mg of ipamorelin, lyophilized together as a single 10 mg cake. The first component is a 29-residue analogue of growth hormone-releasing hormone (GHRH), also called modified GRF (1-29). The second is a five-residue synthetic peptide that binds the ghrelin receptor. The two have nothing in common chemically: they differ in size by a factor of nearly five, act at different receptors, and come from different research programs. The CJC-1295 + Ipamorelin product page lists the vial and its lot records.

Component one: CJC-1295 without DAC, a GHRH-receptor analogue#

GHRH is a hypothalamic hormone whose first 29 residues, with an amidated C-terminus, form sermorelin, which was once FDA-approved under the brand name Geref and has since been withdrawn from the market.^[1] Modified GRF (1-29) is sermorelin with four residues changed: D-alanine at position 2, glutamine at 8, alanine at 15 and leucine at 27. Those substitutions, and the fact that the registered substance called CJC-1295 is a longer molecule, can be read from the FDA's Global Substance Registration System record for CJC-1295 (UNII 62RC32V9N7, CAS 446262-90-4), which describes the same 29 residues followed by a lysine carrying a maleimidopropionyl group, the albumin-binding "Drug Affinity Complex" or DAC.^[2]

That distinction matters here because the blend contains the 29-residue peptide without the DAC lysine. The published human studies of CJC-1295 used the DAC conjugate. In healthy adults the investigators measured increases in mean growth hormone and IGF-I lasting days after a single administration and estimated a half-life of 5.8 to 8.1 days;^[3] in healthy men they measured a 7.5-fold rise in trough growth hormone with no change in the frequency or size of growth hormone pulses.^[4] That long action depends on albumin binding and cannot be assumed for the peptide in this vial. Our companion article on CJC-1295 with and without DAC covers the naming confusion in detail, and the single-peptide vial is on the CJC-1295 (no DAC) product page.

Component two: ipamorelin, a ghrelin-receptor agonist#

Ipamorelin is a synthetic pentapeptide, Aib-His-D-2-Nal-D-Phe-Lys-NH2, developed at Novo Nordisk in the 1990s. Several of its residues are not among the twenty standard amino acids: Aib is alpha-aminoisobutyric acid and D-2-Nal is D-2-naphthylalanine. PubChem lists the free peptide with the formula C38H49N9O5, a molecular weight of 711.9 g/mol, CAS number 170851-70-4 and compound identifier 9831659.^[5] The ipamorelin product page lists the same identifiers.

Ipamorelin belongs to the growth hormone secretagogues, compounds that act on the growth hormone secretagogue receptor type 1a (GHS-R1a), the receptor later shown to be the target of the stomach hormone ghrelin. This is a different receptor from the GHRH receptor that CJC-1295 is designed to activate.

Raun et al., European Journal of Endocrinology, 1998#

The founding paper described ipamorelin in rat pituitary cells, anaesthetised rats and swine. In the rat systems it released growth hormone with a potency and efficacy similar to the older hexapeptide GHRP-6. In swine, its growth hormone response resembled GHRP-6, but unlike GHRP-6 and related compounds it did not significantly raise ACTH or cortisol, even at exposures far above those producing half-maximal growth hormone release. The authors described it as the first agonist of this receptor class with selectivity for growth hormone release similar to that of GHRH. The work was in cells, rats and pigs.^[6]

Beck et al., International Journal of Colorectal Disease, 2014#

Because ghrelin also influences gut motility, ipamorelin was later tested as a candidate treatment for postoperative ileus. This randomized, double-blind, placebo-controlled phase 2 proof-of-concept trial enrolled 117 patients after bowel resection. Its primary endpoint, time to tolerance of a standardized solid meal, did not differ significantly between ipamorelin and placebo, and the compound has not been approved.^[7]

Why GHRH and ghrelin-receptor peptides are discussed together#

The pairing comes from a line of endocrine research in the late 1980s and 1990s that compared the two receptor pathways and gave them together. None of that work used either component of this blend; it used full-length GHRH and the hexapeptide that became known as GHRP-6.

In a 1990 study in 18 healthy men, Bowers and colleagues gave the synthetic hexapeptide His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 alone, GHRH(1-44)NH2 alone, and the two together, measuring serum growth hormone along with prolactin, LH, TSH and cortisol. At submaximal amounts of the hexapeptide, the combination produced a growth hormone response the authors described as synergistic, meaning larger than would be expected from adding the separate responses. They concluded that the two act through independent mechanisms.^[8]

A 1994 study by Popovic and colleagues in the same journal compared GHRH, GHRP-6 and the combination in 12 healthy subjects and 11 patients with active acromegaly, measuring growth hormone as area under the curve over 120 minutes. In the healthy subjects the combination exceeded the sum of the separate responses; in the patients with growth hormone-secreting pituitary adenomas it did not. The authors concluded that the synergy appears to require hypothalamic involvement, and that its mechanism was not established.^[9]

What has not been studied about this blend#

No published study has examined CJC-1295 without DAC and ipamorelin as a combination, in any ratio, in any system. The synergy literature used different molecules (GHRH(1-44) or GHRH(1-29) and GHRP-6), and its findings describe those molecules in the settings where they were tested. Whether a GHRH analogue lacking albumin binding and a selective ghrelin-receptor pentapeptide reproduce that interaction is an open question, not a result.

• No published pharmacology, stability or safety data for the two peptides in one vial.
• Human CJC-1295 data come from the DAC conjugate, a different molecule.
• Ipamorelin's human trial did not meet its primary endpoint, and its selectivity data are from rats and pigs.
• Neither peptide is approved by any regulator.

Regulatory status of CJC-1295 and ipamorelin#

The FDA's list of bulk drug substances that may present significant safety risks in compounding places ipamorelin acetate in category 2 under the 503B interim policy, citing a possible risk of immunogenicity, the complexity of characterizing a peptide with unnatural amino acids, and a literature report of serious adverse events, including death. Ipamorelin acetate also appears in the withdrawn-nominations table for certain other injectable routes. CJC-1295 appears on the same page among withdrawn nominations, where the agency cites serious adverse events including increased heart rate and a systemic vasodilatory reaction and notes that clinical data are limited.^[10] The World Anti-Doping Agency's 2026 Prohibited List names both in section S2.2.4, CJC-1295 among the GHRH analogues and ipamorelin among the growth hormone secretagogues, a class prohibited at all times.^[11]

What a CJC-1295 ipamorelin blend COA should show#

A two-peptide vial raises questions that a single-peptide vial does not. Because the components differ so much in size, mass spectrometry separates them easily: the report should confirm a mass consistent with the 29-residue CJC-1295 peptide (about 3,368 g/mol average mass, calculated from its sequence) and a mass consistent with ipamorelin (711.9 g/mol for the free peptide). A mass near 3,647 would indicate the DAC conjugate instead. The HPLC chromatogram should show a peak assigned to each peptide, and the strongest reports state the measured amount or ratio of each against the 5 mg and 5 mg on the label, since a single purity figure does not confirm the ratio. The lot number, method, laboratory and date complete the record.

Our guide to peptide blends explains how blend reports work and how to compare listings, and reading a Certificate of Analysis covers the general format. The COA library lists every Renuvia lot and its current testing status, marked pending until the laboratory issues the report.