Ipamorelin and CJC-1295: The Research Record From Novo Nordisk to the FDA Votes

LynxLab · 24 October 2026 · 9 min read

Where ipamorelin and CJC-1295 came from, what Raun's 1998 paper, Helsinn's ileus trials and ConjuChem's halted 2006 study found, and their FDA status in 2026.

Photo: Mauro Romero, Unsplash

Ipamorelin and CJC-1295 are sold together so often that the pairing can look like a single product with a single history. It is not. One peptide came out of a Novo Nordisk chemistry programme in Denmark in the late 1990s and ended up in American bowel surgery trials.

The other was designed by a Montreal biotech whose clinical programme stopped in 2006 after a death in a phase 2 study. Neither has ever been approved as a medicine, and in late 2024 a US advisory committee voted against both.

Ipamorelin began as a Novo Nordisk chemistry project

Kirsten Raun and six colleagues at Novo Nordisk's Health Care Discovery unit described ipamorelin in the European Journal of Endocrinology in November 1998. It is a pentapeptide, five amino acids written Aib-His-D-2-Nal-D-Phe-Lys-NH2, and every author on the paper was a Novo Nordisk employee at the company's sites in Gentofte and Måløv.

The compound was found, as Raun put it, "as an outcome of a major chemistry programme" among a series of molecules lacking the central Ala-Trp dipeptide of growth hormone-releasing peptide 1 (GHRP-1). In primary rat pituitary cells it released GH with a potency close to GHRP-6, with an EC50 of 1.3 nanomoles per litre against 2.2 for GHRP-6.

Using receptor antagonists, the team showed ipamorelin acted through the GHRP receptor rather than the GHRH receptor. That receptor was later identified as the ghrelin receptor, which is why ipamorelin is now described as a ghrelin mimetic. It is the second peptide in a cjc-1295 + ipamorelin vial, and the two act on different receptors.

Why Raun called it the first selective secretagogue

The 1998 paper's title claims ipamorelin as "the first selective growth hormone secretagogue", and the selectivity data came from pigs. None of the secretagogues tested changed FSH, LH, prolactin or TSH. GHRP-6 and GHRP-2 both raised ACTH and cortisol. Ipamorelin did not, even at doses more than 200-fold above its ED50 for GH release.

Raun's group wrote that this was "very surprising" and concluded that ipamorelin was "the first GHRP-receptor agonist with a selectivity for GH release similar to that displayed by GHRH". The closing line called it "a very interesting candidate for future clinical development".

That selectivity claim is the main reason ipamorelin, rather than GHRP-6 or GHRP-2, is the ghrelin-receptor agonist researchers pair with a GHRH analogue in a cjc 1295 ipamorelin blend.

Novo Nordisk never brought ipamorelin to market

The clinical development Raun anticipated did not happen at Novo Nordisk, and it did not happen for growth hormone deficiency. When ipamorelin next appears in the public record it is in a different company's hands and aimed at a different organ.

The ClinicalTrials.gov entry NCT00672074 lists Helsinn Therapeutics (U.S.) as sponsor of a phase 2 study that began in April 2008. The indication was post-operative ileus, the stall in gut movement that follows abdominal surgery. The logic was that ghrelin itself is a prokinetic hormone, so a long-lived ghrelin-receptor agonist might restart the bowel sooner.

The minutes of the FDA's October 2024 committee meeting confirm the gap: the agency evaluated ipamorelin for two nominated uses, growth hormone deficiency and post-operative ileus, and the peptide is approved for neither. Anyone looking at cjc-1295 and ipamorelin for research should know that the human data on ipamorelin come almost entirely from this gut programme, not from GH studies.

Helsinn's post-operative ileus trials

The first Helsinn study enrolled 117 adults undergoing small or large bowel resection at 19 US hospitals between April 2008 and December 2009. Patients received intravenous ipamorelin at 0.03 mg per kg twice daily, or placebo, from the first day after surgery for up to seven days. David Beck, Brian Sweeney and Martin McCarter published the results in the International Journal of Colorectal Disease in 2014.

The key endpoint was time to tolerating a standard solid meal. The median was 25.3 hours on ipamorelin and 32.6 hours on placebo, a difference that did not reach statistical significance (p = 0.15). Treatment-emergent adverse events occurred in 87.5% of the ipamorelin group and 94.8% of the placebo group. The authors' conclusion was blunt: "There were no significant differences between ipamorelin and placebo in the key and secondary efficacy analyses."

Design: multicentre, double-blind, placebo-controlled phase 2
Patients: 117 enrolled, 114 analysed
Primary result: 25.3 vs 32.6 hours to first tolerated meal, p = 0.15
Follow-on: a 320-patient dose-finding phase 2 study, NCT01280344, ran from April 2011 to May 2014

The Beck paper noted that results from the larger dose-finding study were pending. The FDA's bulk substances page later recorded that "a study published in literature identified serious adverse events including death when ipamorelin was administered intravenously for improving gastric motility". Nothing further has been published, and ipamorelin remains unapproved for any use in the US, UK or EU. UK buyers searching for cjc-1295 + ipamorelin uk are buying a research compound, not a failed drug repackaged.

CJC-1295 began at ConjuChem in Montreal

CJC-1295 has a separate origin. ConjuChem Biotechnologies, a Montreal company, built it on a platform called the drug affinity complex, or DAC. The core is a modified 29-amino-acid fragment of growth hormone-releasing hormone with four substituted residues. The DAC version adds a reactive group that bonds to serum albumin in the bloodstream after injection, which stretches the half-life from minutes to days. The form in a cjc ipamorelin research vial is normally the short-acting one without DAC.

Jetté and colleagues at ConjuChem published the rat work in Endocrinology in 2005, and Teichman and colleagues published two human trials in healthy adults in the Journal of Clinical Endocrinology and Metabolism in 2006, reporting a half-life of 5.8 to 8.1 days. The structural detail, and what the two forms of CJC-1295 mean for a study, is covered in a companion post on cjc 1295 with dac versus Mod GRF 1-29.

ConjuChem's commercial target was HIV-associated lipodystrophy, the fat redistribution seen in some people on antiretroviral therapy. Researchers who buy cjc-1295 + ipamorelin today are working with a molecule whose only disease-focused trial never reported.

July 2006: the lipodystrophy trial stopped

ConjuChem registered a phase 2 trial, NCT00267527, in December 2005: a multicentre, randomised, placebo-controlled, double-blind study of CJC-1295 given for 12 weeks to HIV-infected patients with visceral obesity. ClinicalTrials.gov lists its status as terminated.

The FDA's December 2024 briefing document summarises what happened. Patients received once-weekly injections in an escalating low-dose arm (60, 90, then 120 micrograms per kg), an escalating high-dose arm (60, 120, then 240 micrograms per kg), or placebo. Two hours after an eleventh weekly dose, one patient complained of chest discomfort. An ECG confirmed an acute myocardial infarction, and the patient died about an hour later.

The FDA briefing states that "ConjuChem Biotechnology withdrew CJC-1295 DAC from clinical trials in 2006 after the death of a subject involved in a phase 2 trial". ConjuChem did not restart the programme.

The FDA's position in 2026

Both peptides have been through the FDA's compounding review, which decides whether US pharmacies may make medicines from a bulk ingredient that is not an approved drug. On 29 September 2023 the agency placed ipamorelin acetate in category 2, its list of substances that "may present significant safety risks", citing immunogenicity, aggregation and the presence of unnatural amino acids that complicate characterisation.

On 29 October 2024 the Pharmacy Compounding Advisory Committee voted on ipamorelin for growth hormone deficiency and post-operative ileus. The final summary minutes record 0 yes, 12 no and 1 abstention for ipamorelin free base, and the same result for ipamorelin acetate. Members who voted no "agreed that there was a lack of information supporting safety and efficacy shown in the available data".

On 4 December 2024 the same committee voted on five forms of CJC-1295. The minutes of that meeting record 13 to 0 against the free base and against each of the three DAC forms, and 12 to 1 against CJC-1295 acetate.

The FDA's category 2 page, current as of 22 April 2026, still lists ipamorelin acetate in category 2 under the 503B policy. CJC-1295 and the 503A nomination for ipamorelin now sit in a separate table of substances "withdrawn by the nominators". Withdrawal is not approval. Neither peptide is on the list of substances US pharmacies may compound, and neither is an approved drug anywhere.

Sport and the UK position

The World Anti-Doping Agency's 2026 Prohibited List, in force since 1 January 2026, names both compounds under S2.2.4. CJC-1295 is listed as a GHRH analogue alongside sermorelin and tesamorelin. Ipamorelin is listed as a growth hormone secretagogue alongside ibutamoren and macimorelin. Both are prohibited at all times, in and out of competition.

In the UK neither peptide is a licensed medicine. They are supplied for laboratory research, and the only honest description of the evidence base is the one above: one positive pharmacology paper from 1998, two inconclusive surgical trials, two healthy-volunteer pharmacokinetic studies, and one terminated phase 2.

LynxLab stocks cjc-1295 ipamorelin 5+5mg for research use as a single 5mg + 5mg blend vial at £42.99, with both peptides tested to 99% purity and the lab report on the product page. The batch certificate of analysis covers both peptides.

Frequently asked questions

Who invented ipamorelin?

Ipamorelin was developed at Novo Nordisk in Denmark and described by Kirsten Raun and colleagues in the European Journal of Endocrinology in November 1998. The paper identifies it as the product of a large in-house chemistry programme built around GHRP-1.

Did ipamorelin fail its clinical trials?

The one published trial, Beck et al. 2014, found no significant difference between ipamorelin and placebo in time to tolerating a solid meal after bowel surgery (25.3 vs 32.6 hours, p = 0.15). A larger 320-patient dose-finding study, NCT01280344, completed in 2014; its results were listed as pending when Beck's paper appeared, and no approval followed.

Why was the CJC-1295 trial stopped in 2006?

A patient in ConjuChem's phase 2 lipodystrophy trial died of a myocardial infarction about three hours after an eleventh weekly dose. The trial's physician attributed it to asymptomatic coronary artery disease, but ConjuChem terminated the study and the FDA records that the data were never published.

Is CJC-1295 Ipamorelin FDA approved?

No. Neither peptide is an approved drug. The FDA's Pharmacy Compounding Advisory Committee voted against adding ipamorelin to the 503A compounding list in October 2024 and against all five forms of CJC-1295 in December 2024. Ipamorelin acetate remains on the FDA's category 2 safety-risk list.

Are ipamorelin and CJC-1295 banned in sport?

Yes. Both are named on the WADA 2026 Prohibited List under section S2.2.4, growth hormone releasing factors, and are prohibited at all times. UK Anti-Doping applies the same list to athletes in the UK.

Sources

Research use only

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