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Ipamorelin

Also known as: NNC 26-0161, Ipamorelina, Ipamoreline

Research Only

Molecular Formula

C38 H49 N9 O5 Fr Ba

Molecular Weight

711.85 Da (Free Base; Acetate salt variable)

Half-Life

~2 hours (terminal half-life after IV infusion in healthy men; subcutaneous PK unestablished)

Sequence

Aib-His-D-2-Nal-D-Phe-Lys-NH2

Clinical Applications & Evidence

Mechanism of Action

Ipamorelin selectively binds and activates the ghrelin receptor GHSR-1a on pituitary somatotrophs, signaling primarily through the Gαq/11–phospholipase C–IP3/DAG pathway to trigger intracellular calcium release and pulsatile growth hormone (GH) secretion. Systemic GH subsequently stimulates hepatic IGF-1 synthesis. Acute preclinical studies demonstrated high selectivity for GH without acutely elevating ACTH, cortisol, or prolactin.

Investigated Uses

  • Postoperative gastrointestinal recovery (Historical Phase 2 trials; a 117-patient bowel resection study failed to demonstrate statistically significant efficacy over placebo)
  • Pituitary GH pulse stimulation (Healthy volunteer IV dose-escalation PK/PD studies)
  • Body composition & lean mass (Preclinical animal models; unproven in human clinical trials)
  • Bone mineral density & sarcopenia (Preclinical rodent research; no human clinical trials)
Early Clinical / Animal Models

Regulatory & Safety Status

FDA Status

Research Only

WADA / Athletic Status

Prohibited at All Times (WADA S4.4.1)

Known Side Effects

Postoperative trial adverse events included nausea, vomiting, abdominal distension, hypokalemia, and hyperglycemiaHeadache, lightheadedness, and transient hunger increase (anecdotal / acute IV observations)Human subcutaneous safety, long-term toxicity, immunogenicity, and carcinogenicity are unstudiedFDA safety assessment notes peptide aggregation and synthesis impurity risks in compounded injectables

Contraindications

  • WADA-tested athletes (Prohibited at all times under S2.2.4 Growth Hormone Secretagogues)
  • Active malignancy or history of hormone-sensitive cancers (Precautionary exclusion due to GH/IGF-1 axis stimulation)
  • Pregnancy and lactation (Unstudied safety profile)
  • Uncontrolled diabetes mellitus or impaired glucose tolerance (Precautionary exclusion)

Drug Interactions

  • CJC-1295 and GHRH analogs (Commonly marketed combination; unstudied in formal clinical drug-interaction trials)
  • Somatostatin analogs (Theoretical inhibition of GH release)

Citations & Clinical Trials

PubMed Ipamorelin: The First Selective GH Secretagogue (1998) Pharmaceutical Research Pharmacokinetics and Pharmacodynamics of Ipamorelin in Healthy Men (1999) Elsevier / USUHS Phase 2 Proof-of-Concept Study of Ipamorelin in Postoperative Ileus (2007) FDA FDA Briefing Document: Ipamorelin — PCAC Meeting (October 2024) World Anti-Doping Agency WADA 2026 Prohibited List — S2.2.4 Growth Hormone Secretagogues