What is ipamorelin, and what does the research show?

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What ipamorelin is

FDA's 2024 evaluation describes ipamorelin as a ghrelin mimetic that stimulates the release of growth hormone from the pituitary gland, and says it was first made by researchers at Novo Nordisk in the mid-1990s.[1] A ghrelin mimetic acts on the same receptor as the hormone ghrelin.[1]

What human research there is

In searches of PubMed, Europe PMC and ClinicalTrials.gov on October 8, 2026, the published reports we found in which ipamorelin was given to people and results for it were reported were a 1999 study of intravenous infusions in healthy men, a 2014 trial of infusions in adults after bowel surgery and a 2015 anti-doping study of one volunteer.[2][3][4]

In searches of PubMed, Europe PMC, Crossref and ClinicalTrials.gov on October 8, 2026, we found no published study in people that tested ipamorelin for aging, body composition, weight loss, sleep, muscle or injury recovery, sexual function or cognition. The searches covered titles and abstracts, and the full text of open-access papers in Europe PMC, so a study that mentions ipamorelin only inside a paywalled paper could have been missed.

Growth hormone levels in healthy men

In a 1999 study, healthy men received ipamorelin by intravenous infusion at five dose levels.[2] According to the study's abstract, growth hormone in the blood showed a single peak at 0.67 hours, about 40 minutes, and then fell to negligible levels at every dose.[2] The 1999 study measured hormone levels and did not test any health outcome.[2]

The abstract of the 1999 study and FDA's account of it give different totals for the number of men studied, so we state none.

Ipamorelin is not an FDA-approved drug for any use, according to FDA's evaluation of ipamorelin-related bulk drug substances (memo dated August 19, 2024; checked October 14, 2026).

The bowel surgery trials

A 2014 randomized, double-blind, placebo-controlled trial tested ipamorelin in adults in hospital after bowel resection surgery.[3] The trial was funded by its sponsor, Helsinn Therapeutics.[3] Of 117 patients enrolled, 114 were included in the analysis.[3] The patients received ipamorelin or placebo by intravenous infusion twice daily for up to 7 days.[3]

In that trial, the median time to the first tolerated solid meal was 25.3 hours with ipamorelin and 32.6 hours with placebo, a difference that was not statistically significant (p = 0.15).[3] The authors described the study as small. We read the study's abstract and FDA's account of it, and did not read the full paper.

ClinicalTrials.gov lists a second, larger trial by the same sponsor in people recovering from bowel resection, with 320 participants, and the record shows it as completed in 2014 with no results posted when we checked on October 8, 2026.[5] Among records that name ipamorelin in the title or abstract, our searches of PubMed and Europe PMC on October 8, 2026 found no publication of that second trial.

FDA's 2024 evaluation says development of ipamorelin as a treatment for postoperative ileus was reportedly discontinued.[1]

Ipamorelin is not an FDA-approved drug for any use, according to FDA's evaluation of ipamorelin-related bulk drug substances (memo dated August 19, 2024; checked October 14, 2026).

Growth hormone deficiency

According to FDA's 2024 evaluation, FDA has not identified data to support the effectiveness of ipamorelin for diagnosing or treating growth hormone deficiency in children or adults.[1]

Ipamorelin is not an FDA-approved drug for any use, according to FDA's evaluation of ipamorelin-related bulk drug substances (memo dated August 19, 2024; checked October 14, 2026).

Marketed uses and combinations

In its 2024 evaluation, FDA found clinics marketing ipamorelin for other uses, including weight loss and muscle building.[1] In searches of PubMed, Europe PMC and ClinicalTrials.gov on October 8, 2026, we found no published human study of ipamorelin combined with CJC-1295 or sermorelin.

A 2026 review in an endocrinology journal says the practice of combining ipamorelin with CJC-1295 'is largely driven by anecdotal rationale'.[6]

Ipamorelin is not an FDA-approved drug for any use, including weight loss, muscle building, anti-aging or longevity, according to FDA's evaluation of ipamorelin-related bulk drug substances (memo dated August 19, 2024; checked October 14, 2026).

Animal research

In its 2024 evaluation, FDA describes studies in which ipamorelin raised growth hormone in rats and pigs, and studies in which it sped up gut movement in rats after abdominal surgery.[1] In a mouse study, ipamorelin increased body fat relative to body weight.[7] Results in animals do not show what happens in people.

FDA's 2024 memo says it did not identify published animal studies of ipamorelin's effects on reproduction or development.[1] FDA's 2024 memo describes a mouse study in which treatment with ghrelin, a hormone that acts on the same receptor, or with a drug that blocks that receptor negatively affected fertilization and embryo development, and says it is not yet known whether ipamorelin does the same.[1]

Ipamorelin is not an FDA-approved drug for any use, including weight loss, muscle building, anti-aging or longevity, according to FDA's evaluation of ipamorelin-related bulk drug substances (memo dated August 19, 2024; checked October 14, 2026).

Anti-doping

The World Anti-Doping Agency's 2026 Prohibited List, in effect from January 1, 2026, names ipamorelin among growth hormone secretagogues that are prohibited at all times.[8]

Evidence table

Evidence levels in this table follow our grading key. Emerging means some human evidence that falls short of consistent randomized trials, such as small or single trials. Evidence against means a controlled trial tested the claim on its main outcome in the people it studied and did not find the effect.

Not graded means we give no level, here because the searches named in that row found no study that supports the claim. A search that finds no study does not show that none exists.

Is ipamorelin FDA-approved?

Ipamorelin is not an FDA-approved drug for any use, according to FDA's evaluation of ipamorelin-related bulk drug substances (memo dated August 19, 2024; checked October 14, 2026).

There is no FDA-approved ipamorelin drug product for any use, according to FDA's evaluation of ipamorelin-related bulk drug substances (memo dated August 19, 2024). The evaluation covered ipamorelin free base and ipamorelin acetate, and FDA states that 'neither is a component of an FDA-approved drug.'

Compounded ipamorelin is not FDA-approved. FDA states: 'Compounded drugs are not FDA-approved. This means that FDA does not verify the safety, effectiveness or quality of compounded drugs before they are marketed.' FDA's page 'Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks' (FDA page content current as of April 22, 2026) lists ipamorelin acetate under the heading 'Bulk drug substances under category 2 of the interim policies'.

Ipamorelin acetate is listed under '503B Category 2: Bulk Drug Substances that Raise Significant Safety Risks' in FDA's document on bulk drug substances nominated for use in compounding under section 503B (updated March 21, 2025).

Regulatory status checked October 14, 2026. Sources: www.fda.gov/…/download; www.fda.gov/…/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks; www.fda.gov/…/download; www.fda.gov/…/compounding-and-fda-questions-and-answers

Risks and side effects

In the 2014 bowel surgery trial, which enrolled 117 patients and gave the drug for up to 7 days, the abstract reports that 87.5% of patients given ipamorelin and 94.8% of those given placebo had at least one adverse event during treatment, and its authors concluded that the drug was well tolerated.[3] In its 2024 evaluation of the same paper, FDA noted that low potassium, insomnia and high blood sugar at discharge were reported more often with ipamorelin than with placebo.[1] These were patients recovering from major bowel surgery.[3] The 2014 bowel surgery trial was funded by its sponsor, Helsinn Therapeutics.[3]

FDA's page 'Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks' (FDA page content current as of April 22, 2026) says: 'A study published in literature identified serious adverse events including death when ipamorelin was administered intravenously for improving gastric motility.' In its evaluation of ipamorelin-related bulk drug substances (memo dated August 19, 2024), FDA describes a clinical study in which people with postoperative ileus received ipamorelin intravenously and two deaths were reported. FDA wrote that 'it is unclear whether the two deaths were related to ipamorelin.' It also wrote that 'their occurrence in ipamorelin-treated subjects raises safety concerns about the use of ipamorelin in compounding.'

On its page 'Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks' (FDA page content current as of April 22, 2026), FDA says that compounded drugs containing ipamorelin acetate 'may pose risk for immunogenicity for certain routes of administration due to the potential for aggregation or peptide-related impurities.' FDA adds: 'FDA has not identified safety-related information regarding ipamorelin acetate via certain other injectable routes of administration.' It concludes that 'the agency lacks sufficient information to know whether the drug would cause harm if administered to humans via those routes.'

FDA page

FDA's account does not say whether any patient in the placebo group died.[1]

FDA's 2024 evaluation says it found no safety data for ipamorelin given by injection under the skin, and no data on how the drug is absorbed or how the body responds to it by that route.[1]

FDA's 2024 evaluation says the agency is concerned that ipamorelin could carry risks like those listed in the labels of growth hormone products, such as glucose intolerance, fluid retention and an increased risk of tumors, because it stimulates growth hormone.[1] FDA reasoned from how the drug works and wrote that there are not enough data to conclude that ipamorelin would not raise such concerns.[1] The listed effects come from the labels of other products and are not a finding from a study of ipamorelin.

FDA's 2024 evaluation concluded that ipamorelin is not well characterized physically and chemically, in part because it found no data on impurities, aggregates or bacterial endotoxins in the published literature.[1]

If you are thinking about using ipamorelin, talk to a licensed clinician first.

If you have severe symptoms, call 911 or seek emergency care. Report side effects to FDA MedWatch.

Related pages

• What Does FDA-Approved Mean?
• Compounded Medications Explained