--- title: "Ipamorelin" canonical_url: https://bestpeptidecalculator.app/library/ipamorelin description: "Pentapeptide ghrelin-receptor agonist noted for GH release with relatively less ACTH/cortisol than older GHRPs. Not FDA-approved. WADA S2 (named)." updated: 2026-09-26 publisher: Peptide Library notice: "Research and educational use only. Not medical advice." --- # Ipamorelin Ipamorelin (also called NNC 26-0161 or Aib-His-D-2-Nal-D-Phe-Lys-NH2) is a research peptide in the Growth Hormone Secretagogue class. Ipamorelin is a synthetic pentapeptide agonist at growth hormone secretagogue receptor 1a, the ghrelin receptor, on pituitary somatotrophs and hypothalamic neurons. Pentapeptide ghrelin-receptor agonist noted for GH release with relatively less ACTH/cortisol than older GHRPs. Not FDA-approved. WADA S2 (named). Also known as: NNC 26-0161, Aib-His-D-2-Nal-D-Phe-Lys-NH2. Categories: Fat Loss, Muscle/Recovery, Experimental. ## Classification - Type: Selective GHS / research - Mechanism class: Growth Hormone Secretagogue - Development stage: Research only - Regulatory class: Research compound, not FDA-approved ## Mechanism Ipamorelin is a synthetic pentapeptide agonist at growth hormone secretagogue receptor 1a, the ghrelin receptor, on pituitary somatotrophs and hypothalamic neurons. It is notable within the class for selectivity: in published human and animal studies it releases growth hormone with little effect on cortisol, prolactin or aldosterone, and without the marked appetite stimulation characteristic of GHRP-6. Because it acts through the ghrelin receptor rather than the GHRH receptor, its effect is additive with GHRH analogs, which is the pharmacological basis for combining the two classes. It is not approved for any use. Targets: GHSR. Origin: Synthetic pentapeptide GHS. ## Properties - Molecular formula: C38H49N9O5 - Molecular weight: 711.9 g/mol - CAS number: 170851-70-4 - Half-life: Terminal half-life approximately 2 hours (human, intravenous) - Studied routes: Intravenous ## Evidence - Evidence level: Limited Human Evidence - Highest documented: Controlled human trials - Human trials: 2 - Controlled human trials: 1 - Preclinical sources: 0 - Latest source: 2014 Each step shows whether the sources Peptide Library has reviewed include that kind of research. Counts are reviewed sources, not every study ever published. Reviews and programme summaries that describe human use are shown as "reported", not as trials, and registered trials without published results are listed but not counted. A higher step means research has progressed further; it does not mean a compound works better or is safer. Compounds whose evidence has not been reviewed yet show "Not reviewed" instead of a guess. ### Studies 1. Gobburu JV et al. Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers. Pharm Res. 1999. 1999. Human study (early or uncontrolled). Population: Healthy male volunteers, 8 per dose level. Ipamorelin pharmacokinetics and growth hormone release [Source](https://pubmed.ncbi.nlm.nih.gov/10496658/) 2. NCT01280344 — Safety and Efficacy of Ipamorelin Compared to Placebo for the Recovery of Gastrointestinal Function. 2014. Human study (early or uncontrolled). Population: Patients recovering gastrointestinal function after surgery (n=320). Recovery of gastrointestinal function. Limitations: Registered trial with no published results yet. [Source](https://clinicaltrials.gov/study/NCT01280344) 3. Prospective, randomized, controlled, proof-of-concept study of the ghrelin mimetic ipamorelin for the management of postoperative ileus. Int J Colorectal Dis. 2014. 2014. Controlled human trial. Population: Adults after small or large bowel resection (117 enrolled, 114 analysed). Time to first tolerated solid meal (no significant difference versus placebo, p = 0.15) [Source](https://pubmed.ncbi.nlm.nih.gov/25331030/) ### Registered trials - [NCT01280344](https://clinicaltrials.gov/study/NCT01280344) ## Safety Side effects: Headache; Flushing; Water retention. Risks: WADA S2 prohibited. Contraindications: Avoid with diabetes; Not recommended during pregnancy. Human safety basis: Limited human reports Key limitations: Not approved by the FDA for any use.. ## Regulatory status Ipamorelin is not an FDA-approved product. It is sold for laboratory research and has no approved medical use. - FDA status: Not Approved - WADA status: Banned in Sport - Availability: Research-Only ## Frequently asked questions ### What is Ipamorelin? Pentapeptide ghrelin-receptor agonist noted for GH release with relatively less ACTH/cortisol than older GHRPs. Not FDA-approved. WADA S2 (named). Ipamorelin is a synthetic pentapeptide agonist at growth hormone secretagogue receptor 1a, the ghrelin receptor, on pituitary somatotrophs and hypothalamic neurons. It is notable within the class for selectivity: in published human and animal studies it releases growth hormone with little effect on cortisol, prolactin or aldosterone, and without the marked appetite stimulation characteristic of GHRP-6. ### What are the side effects of Ipamorelin? Ipamorelin has only limited human data, so its side-effect profile is not well established. Effects recorded on this profile include headache, flushing and water retention. Cautions recorded on this profile: avoid with diabetes and not recommended during pregnancy. It is on the WADA Prohibited List for athletes. This is reference information, not medical advice. ### How does Ipamorelin work? Ipamorelin is a synthetic pentapeptide agonist at growth hormone secretagogue receptor 1a, the ghrelin receptor, on pituitary somatotrophs and hypothalamic neurons. It is notable within the class for selectivity: in published human and animal studies it releases growth hormone with little effect on cortisol, prolactin or aldosterone, and without the marked appetite stimulation characteristic of GHRP-6. ### Is Ipamorelin FDA approved? No. Ipamorelin is not approved by the FDA for any indication and is categorised as research-only. It has not been reviewed for safety or efficacy as a medicine, and published research should be read as investigation rather than established use. FDA's compounding lists show 503A nomination: Previously in Category 2; nomination withdrawn by the nominators; 503B Category 2: FDA identified significant safety risks. ### What is the half-life of Ipamorelin? Reported half-life for Ipamorelin is ~2 hours. Half-life describes how long the compound persists in circulation, not how long any effect lasts, and published figures vary with route of administration, formulation and the population studied. ### Is Ipamorelin banned in sport? Ipamorelin is recorded here as prohibited in sport. Athletes subject to anti-doping rules should check the current WADA Prohibited List directly, since it is revised annually and classifications change. ### What peptides are similar to Ipamorelin? Compounds most often compared with Ipamorelin include GHRP-6, GHRP-1, Pralmorelin (GHRP-2) and Hexarelin (Examorelin). They are grouped by shared mechanism or research area rather than by equivalence, and their regulatory status and evidence base differ. ## References - [WADA Prohibited List 2026](https://www.wada-ama.org/en/prohibited-list) - [The influence of ghrelin agonist ipamorelin acetate on the hypothalamic-pituitary-testicular axis in a cichlid fish, Oreochromis mossambicus — Anim Reprod Sci, 2024](https://pubmed.ncbi.nlm.nih.gov/38996787/) - [The growth hormone secretagogue receptor 1a agonists, anamorelin and ipamorelin, inhibit cisplatin-induced weight loss in ferrets: Anamorelin also exhibits anti-emetic effects via a central mechanism — Physiol Behav, 2024](https://pubmed.ncbi.nlm.nih.gov/39043357/) - [Therapeutic Peptides in Orthopaedics: Applications, Challenges, and Future Directions — J Am Acad Orthop Surg Glob Res Rev, 2026](https://pubmed.ncbi.nlm.nih.gov/41490200/) - [Injectable Peptide Therapy: A Primer for Orthopaedic and Sports Medicine Physicians — Am J Sports Med, 2026](https://pubmed.ncbi.nlm.nih.gov/41476424/) - [Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance — Sports Med, 2026](https://pubmed.ncbi.nlm.nih.gov/41966639/) Note: Dose figures are left out of this Markdown version. See the cited sources.