Ipamorelin FAERS Safety Signals: What the Post-Market Data Actually Shows

What safety data exists for ipamorelin?

Ipamorelin is not a component of any approved product, and it has no US Pharmacopeia monograph [1].

One published phase 2 trial tested ipamorelin in adults after bowel resection. It enrolled 117 patients and analyzed 114, who were randomized to 0.03 mg/kg intravenous ipamorelin or placebo twice daily from postoperative day 1 to 7 [3]. Median time to tolerate a 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]. Any treatment-emergent adverse event occurred in 87.5% of the ipamorelin group and 94.8% of the placebo group [3].

FDA's summary of that trial gives these adverse-event rates: low potassium in 12.5% of ipamorelin patients versus 3.4% on placebo, insomnia in 10.7% versus 5.2%, and high blood sugar at discharge in 14.3% versus 8.6% [1]. Serious adverse events were 17.9% versus 15.5% [1]. Two ipamorelin-treated patients died of surgical complications after bowel surgery for colon cancer with anastomotic leak. FDA said it is unclear whether the deaths were related to ipamorelin but that they raise safety concerns [1].

The other human dataset is a dose-escalation study of 15-minute intravenous infusions in healthy men, from 4.21 to 140.45 nmol/kg, with eight men at each dose level. Half-life was about 2 hours, and growth hormone rose in a single sharp peak about 0.67 hours after the infusion [4].

What FDA says the risks are

FDA lists ipamorelin acetate among bulk substances that may present significant safety risks for outsourcing facilities. Its stated concerns are possible immunogenicity for certain routes because of aggregation and impurities, unnatural amino acids that complicate characterization, and a study in the literature that identified serious adverse events including death when ipamorelin was administered intravenously for improving gastric motility [2]. FDA also said it has not identified safety-related information for other injectable routes [2].

FDA has said ipamorelin stimulates the GH and IGF-1 axis, so it may carry the risks listed on approved growth hormone labels, among them neoplasm, glucose intolerance and diabetes, intracranial hypertension, fluid retention, hypothyroidism and pancreatitis, and, like the approved GH stimulator macimorelin, possibly QT prolongation. FDA found no data showing it would not [1].

Regulatory status and what is not known

Ipamorelin acetate was added to category 2 on September 29, 2023 and was still on that list on FDA's page dated 04/22/2026 [2][5]. For state-licensed pharmacies and physicians, ipamorelin appears in the nominated-but-withdrawn table and in none of the three categories on FDA's list updated May 14, 2026 [2][8].

On October 29, 2024, FDA's Pharmacy Compounding Advisory Committee voted 0 yes, 12 no and 1 abstention on ipamorelin free base, and the same on ipamorelin acetate. It cited a lack of information supporting safety and efficacy for growth hormone deficiency and postoperative ileus [6]. WADA names ipamorelin in S2.2.4 of its Prohibited List, prohibited at all times [7].

No FDA-approved dose exists, and the human studies used intravenous dosing only. FDA found no human pharmacokinetic, safety or efficacy data for subcutaneous ipamorelin [1][3][4]. A second phase 2 ileus study (NCT01280344) is registered with no results posted. FDA's October 2024 review says it identified only one published ileus study and that development was reportedly discontinued after disappointing results [1]. MedWatch is FDA's program for reporting problems with medical products [9].