Ipamorelin Cognitive Function Impact: What the Evidence Actually Shows

What did the human studies measure?

Beck and colleagues randomized 117 adults having bowel resection to 0.03 mg/kg intravenous ipamorelin or placebo twice daily from day 1 to 7 or discharge; 114 were analyzed. Median time to first tolerated solid meal was 25.3 hours with ipamorelin versus 32.6 with placebo (p=0.15, not significant) [1]. Development was reportedly discontinued after disappointing phase 2 results [3]. The volunteer study gave 15-minute intravenous infusions of 4.21 to 140.45 nmol/kg to healthy men; half-life was about 2 hours, and growth hormone peaked about 0.67 hours after infusion [2].

Where the cognitive hypothesis comes from

The hypothesis draws on ipamorelin's ability to release growth hormone [4] and on research describing IGF-1 as a modulator of brain activity, including cognition [5]. That research does not show that ipamorelin improves cognitive function [3][5]. A 2018 review of growth hormone secretagogues found few long-term controlled studies of the class; it reports possible effects on appetite, lean mass and sleep, and concern about blood glucose [7]. The pharmacology paper that introduced ipamorelin is animal work; it released growth hormone in rats and swine through a GHRP-like receptor, and in swine it did not change FSH, LH, prolactin or TSH [4].

What the safety record shows

FDA lists ipamorelin acetate in category 2 for outsourcing facilities; it was added September 29, 2023 and is still listed on FDA's page dated April 22, 2026 [6][8]. FDA cites possible immunogenicity from aggregation and impurities, unnatural amino acids that complicate characterization, and serious adverse events including death with intravenous use for gastric motility; for other injectable routes it has not identified safety information [6]. In the ileus trial, per FDA, low potassium occurred in 12.5% versus 3.4% on placebo, insomnia in 10.7% versus 5.2%, high blood sugar at discharge in 14.3% versus 8.6%, and serious adverse events in 17.9% versus 15.5%. Two ipamorelin-treated patients died of surgical complications; FDA said it is unclear whether the deaths were related [3]. FDA also says that because ipamorelin stimulates the GH and IGF-1 axis, it may carry risks listed on approved growth hormone labels, such as neoplasm, glucose intolerance and diabetes, intracranial hypertension, fluid retention, hypothyroidism and pancreatitis, and possibly QT prolongation [3].

Regulatory status

Ipamorelin is not FDA-approved, is not a component of any FDA-approved drug and has no US Pharmacopeia monograph [3]. At its October 29, 2024 meeting, FDA's Pharmacy Compounding Advisory Committee voted 0 yes, 12 no, 1 abstention on ipamorelin free base and the same on ipamorelin acetate, citing lack of information supporting safety and efficacy [9]. It is not in HHS's October 2026 draft enforcement-discretion policy [10]. WADA names it in S2.2.4 of its 2026 Prohibited List, prohibited at all times, and in the 2027 List [11][12].