Compound Profile
Ipamorelin: A Secretagogue That Finished Its Trials
Published: August 24, 2026
TL;DR
Most compounds in a research catalogue have an incomplete human record. Ipamorelin is different. It moved from a pharmaceutical discovery program into two completed Phase 2 trials in postoperative ileus. The published study reported that it was well tolerated but did not beat placebo on its primary endpoint. Development stopped after Phase 2. That is an unusually complete scientific outcome: a defined question was tested in randomized trials and received a useful answer.
Curo's ipamorelin research-material page sits within the research-peptide product catalogue. Lot documentation is searchable through the certificate of analysis database, and catalogue materials fall under Curo's research use only policy.
A selective growth hormone secretagogue
Ipamorelin is a pentapeptide growth hormone secretagogue, one of a class studied for signalling the release of growth hormone rather than supplying the hormone itself. It acts at the growth hormone secretagogue receptor GHS-R1a, better known as the ghrelin receptor, and Novo Nordisk chemists arrived at it by stripping a central dipeptide out of the earlier compound GHRP-1.
The word "selective" in the 1998 paper that introduced it is doing specific work. Earlier peptide secretagogues such as GHRP-6 and GHRP-2 raise ACTH and cortisol along with growth hormone. In conscious swine, ipamorelin did not, even at doses more than two hundred times the one producing half its maximal growth hormone effect, and it left prolactin, FSH, LH and TSH alone. That narrow hormonal footprint is the property the name refers to.
FDA's Substance Registration System lists ipamorelin as UNII Y9M3S784Z6. The entry records the molecular formula C38H49N9O5 and cross-references Novo Nordisk's development code NNC 26-0161. Those identifiers connect the chemical record to the candidate that entered formal development.
Ipamorelin also appears frequently beside CJC-1295 in research catalogues. The catalogue includes a page for a CJC-1295 no-DAC and ipamorelin research blend, but a common pairing is not evidence that the combination shares the clinical record of either component. The CJC-1295 DAC and no-DAC comparison explains the identity problem on that side of the pairing. The tesamorelin development profile offers another neighboring record with a different endpoint and regulatory history.
From Novo Nordisk to Helsinn
The NNC 26-0161 code preserves ipamorelin's origin inside Novo Nordisk's discovery work. Clinical development later moved to Helsinn Therapeutics in the United States, which sponsored two studies in postoperative ileus, the temporary slowing of gastrointestinal recovery after surgery.
That indication was not an arbitrary pick. Alongside the pituitary work, ipamorelin was shown to accelerate gastric emptying through GHS-R1a signalling on cholinergic excitatory neurons, and that effect was demonstrated in a rat model of postoperative ileus. The surgical programme followed the mechanism.
NCT00672074 was a randomized Phase 2 trial sponsored by Helsinn Therapeutics (U.S.). It enrolled 117 participants and was completed in December 2009. The next study expanded the program: NCT01280344 was a Phase 2 dose-finding trial after bowel resection, also sponsored by Helsinn Therapeutics. It enrolled 320 participants and was completed in May 2014.
That sequence matters. This was not a laboratory observation followed by years of inference. A corporate candidate entered multicenter human studies, progressed into a larger dose-finding trial, and reached a completed Phase 2 record.
What the ileus trials found
The first study asked whether ipamorelin could shorten the time until a standardized solid meal was tolerated after bowel resection. Beck and colleagues published the results in the International Journal of Colorectal Disease in 2014.
The median time to the first tolerated meal was 25.3 hours in the ipamorelin arm and 32.6 hours with placebo. The difference did not reach statistical significance, with p = 0.15. The authors reported that ipamorelin was well tolerated, but the study did not meet its primary efficacy endpoint.
The larger dose-finding study was completed, and development did not proceed beyond Phase 2. The published result therefore supplies a clear boundary. Ipamorelin showed enough preclinical rationale to justify a real surgical program, but the measured primary endpoint did not establish an advantage over placebo.
A clean negative result is productive science. It narrows uncertainty, separates a plausible mechanism from a demonstrated clinical outcome, and gives later researchers a firmer starting point than an anecdote or an unfinished pilot could provide. Ipamorelin's record is interesting because the central question was asked properly and answered.
Regulatory status in 2026
Four separate documents describe ipamorelin's current standing, and each answers a narrower question than the others.
At its October 29, 2024 meeting, FDA's Pharmacy Compounding Advisory Committee considered the free base and acetate forms for the 503A Bulks List. The approved meeting minutes record a vote of 0 yes, 12 no, and 1 abstention for ipamorelin free base, and the same 0 yes, 12 no, and 1 abstention for ipamorelin acetate. The minutes were approved January 15, 2025.
For outsourcing facilities, ipamorelin acetate appears on FDA's list of bulk drug substances that may present significant safety risks under section 503B, in the version updated March 21, 2025. That 503B listing is distinct from the 503A advisory vote.
An enforcement record provides another important distinction. FDA's January 26, 2022 warning letter to Innoveix Pharmaceuticals cites the firm's July 9, 2021 voluntary recall of a compounded sermorelin and ipamorelin injection because of a lack of sterility assurance. The cited issue was the compounded product's sterility assurance, not the outcome of the Phase 2 ileus study.
Sport rules form a separate layer. WADA's 2026 Prohibited List took effect January 1, 2026. Growth hormone secretagogues, including ipamorelin, sit under section S2 and are prohibited at all times, both in and out of competition. One published enforcement example predates that edition: USADA announced a two-year sanction for UFC athlete David Branch after a May 24, 2019 sample contained ipamorelin. His period of ineligibility began July 26, 2019.
Finally, ipamorelin was not among the substances listed for the July 23 and 24, 2026 Pharmacy Compounding Advisory Committee meeting. The Federal Register notice named BPC-157, KPV, TB-500, MOTS-c, emideltide, semax, and epitalon. The later agenda does not add a new ipamorelin vote.
Documentation for an ipamorelin vial
A vial's documentation should establish what material belongs to that lot. Start by matching the lot number on the label to its report, using Curo's guide to verifying a certificate of analysis against a specific lot.
Then read each analytical method for the question it answers. LC-MS supports molecular identity. HPLC reports chromatographic purity. Endotoxin testing measures endotoxin burden. Those are the three methods in Curo's quality and testing standard. No single one of them substitutes for the other two.
Handling is a separate documentation layer. The guide to storing research peptides and bacteriostatic water explains how storage conditions relate to material integrity after receipt.
Further reading
AOD-9604 followed a similar arc and then took an unexpected turn: development stopped after a missed obesity endpoint, and the compound reappeared years later under a new name in pain research. That history is set out in the AOD-9604 second career.
A finished trial programme is easier to read than one just beginning. For the opposite end of that arc, MOTS-c entered its first registered administration study in February 2026, with results still pending; the registry picture is mapped in Nine MOTS-c trials, one that administers the peptide.
Common questions
Did ipamorelin fail its clinical trials?
The published Phase 2 study did not meet its primary efficacy endpoint. It also reported that ipamorelin was well tolerated. Calling that a completed negative result is more precise than framing the entire research program as either a success or a cautionary tale.
Why were the trials about postoperative ileus?
The development program tested whether a growth hormone secretagogue could improve gastrointestinal recovery after bowel surgery. That was the defined pharmaceutical indication behind both Helsinn-sponsored Phase 2 studies.
Does the CJC-1295 pairing have the same evidence?
No. Catalogue pairings and clinical evidence are different records. The two ileus trials evaluated ipamorelin within their registered study designs, not the common CJC-1295 and ipamorelin combination.
What can a certificate of analysis establish?
It can connect a lot to analytical findings for identity, chromatographic purity, and endotoxin burden when the label and report match. It cannot establish that the material will reproduce a pharmaceutical trial result.