Ipamorelin. A Small Peptide With a Narrow Target
 | |
| PENTAPEPTIDE · GHRELIN RECEPTOR AGONIST | |
| Class | Growth hormone secretagogue (a ghrelin receptor agonist) |
|---|---|
| Sequence | Aib-His-D-2-Nal-D-Phe-Lys-NH2, five building blocks including two unnatural ones |
| Formula | C38H49N9O5, molar mass about 712 g/mol |
| Code name | NNC 26-0161 during development |
| Half-life in people | About 2 hours after an intravenous infusion (1999 study) |
| Originator | Novo Nordisk, Denmark; later trials sponsored by Helsinn Therapeutics (U.S.) |
| Status | Not approved as a medicine anywhere; on the WADA Prohibited List |
Ipamorelin has no marketing authorisation in any country, and the World Anti-Doping Agency lists it by name. Research-grade ipamorelin is intended for laboratory use. This site offers information only.
Ipamorelin is only five amino acids long. Danish chemists picked it in the 1990s because it released growth hormone without the cortisol rise seen with earlier peptides of its kind. It was later tested for gut recovery after surgery. This site sets out what the studies found and what they left open.
- Just five amino acids long
- Half-life of roughly two hours in people
- Named in WADA section S2.2.4
Where Ipamorelin Fits
Growth hormone release is controlled from two directions. One signal, GHRH, comes from the hypothalamus. A second pathway runs through a receptor on pituitary cells that responds to a family of small synthetic peptides, and later turned out to be the receptor for ghrelin, a stomach hormone discovered in 1999.
The first synthetic peptides aimed at that receptor, such as GHRP-6 and GHRP-2, worked well but also pushed up stress hormones like cortisol. A research team at Novo Nordisk in Måløv, Denmark, screened shorter versions and in 1998 described one that released growth hormone with far less spill-over: ipamorelin.
That selectivity made ipamorelin look like a clean research tool and a possible medicine. In practice it was never approved. The pages below cover the chemistry, the animal and human studies, the gut-surgery trials and the anti-doping picture.
Inside This Guide
- What Is Ipamorelin? – The five-part structure, the ghrelin receptor and what selective means
- Origins – From a Danish screening programme to two Phase 2 surgery trials
- Research – Bone, muscle, fat and gut studies, plus the human data
- Rules & Risks – Sport rules, medicines law and the unanswered safety questions
- Sourcing – Brief practical notes for research laboratories