Last updated 11 October 2026 · SARMs Store editorial team. Products on this site are supplied strictly for laboratory research and are not for human consumption. This guide summarises published research; it is not medical advice and contains no instructions for use. 18+ only.
Ipamorelin at a glance
| Class | Synthetic pentapeptide growth hormone secretagogue (ghrelin receptor agonist) |
|---|---|
| Sequence | Aib-His-D-2Nal-D-Phe-Lys-NH2 |
| Developed by | Novo Nordisk, Denmark, 1990s, as NNC 26-0161 |
| Highest evidence | Human pharmacokinetic study in healthy volunteers; phase II trial in post-operative ileus that did not meet its endpoint |
| Studied for | Selective growth hormone release, bone mineral content in rodents, gut motility after surgery |
| CAS number | 170851-70-4 |
| Format | Lyophilised powder in a sealed vial (5mg) |
| UK status 2026 | Research chemical; not licensed anywhere; prohibited in sport under WADA S2 |
What ipamorelin is
Ipamorelin is a five amino acid peptide that acts on the growth hormone secretagogue receptor (GHS-R1a), the receptor that the stomach hormone ghrelin binds. Activating that receptor in the pituitary prompts a pulse of growth hormone. It belongs to the family of growth hormone releasing peptides (GHRPs) that began with GHRP-6 in the 1980s, but it was designed to be more selective than the earlier members: in the original animal work it released growth hormone without the rises in ACTH, cortisol and prolactin seen with GHRP-6 and GHRP-2. That selectivity is the reason it is the GHRP most often discussed today.
Ipamorelin UK: what buyers should know
Ipamorelin is one of the most searched research peptides in the UK, both on its own and alongside CJC-1295. It has never been licensed as a medicine anywhere, so everything sold in the UK is research material. Our Origin Peptides Ipamorelin 5mg is a sealed, batch-numbered lyophilised vial dispatched from our UK warehouse at £49.99, and it is also available blended with CJC-1295 in CJC-1295 + Ipamorelin 10mg.
Ipamorelin names you will see
Ipamorelin appears as ipamorelin, ipamorelin acetate (the salt form), NNC 26-0161 (its Novo Nordisk development code) and by its sequence, Aib-His-D-2Nal-D-Phe-Lys-NH2. Its CAS number is 170851-70-4 and its molecular weight is about 712 g/mol. It is often confused with similarly named compounds: anamorelin and macimorelin are different, orally active ghrelin receptor agonists, and sermorelin and tesamorelin act on a different receptor altogether.
What the research found
Selectivity. Raun and colleagues reported in the European Journal of Endocrinology in 1998 that ipamorelin released growth hormone in rats and pigs with a potency similar to GHRP-6, but did not raise ACTH or cortisol even at doses well above those needed for growth hormone release, unlike GHRP-6 and GHRP-2. The paper described it as the first selective growth hormone secretagogue.
Human pharmacokinetics. Gobburu and colleagues reported in Pharmaceutical Research in 1999 on healthy volunteers given ipamorelin by infusion. Growth hormone rose in a single, dose dependent pulse, and the peptide had a short terminal half-life of about two hours. This remains the main published human pharmacology study.
Bone. Svensson and colleagues reported in the Journal of Endocrinology in 2000 that ipamorelin and GHRP-6 increased bone mineral content in adult female rats over several weeks, which is the basis of the bone research interest.
Gut motility. Because ghrelin also stimulates gut movement, ipamorelin was tested by Helsinn for post-operative ileus, the temporary paralysis of the gut after abdominal surgery. A randomised phase II trial in bowel resection patients, reported by Beck and colleagues in the International Journal of Colorectal Disease in 2014, found no significant difference from placebo in recovery of gut function, and development stopped.
What is missing. Any controlled human trial of ipamorelin for body composition, strength, sleep or ageing, any long term human safety data, and any licence. Claims about those outcomes rest on the mechanism and on animal data.
Ipamorelin compared with other growth hormone secretagogues
| Compound | Receptor | Form | Human record | In our range |
|---|---|---|---|---|
| Ipamorelin | Ghrelin receptor (GHS-R1a) | Lyophilised peptide | Pharmacokinetic study; phase II in post-operative ileus | Ipamorelin 5mg |
| GHRP-6 and GHRP-2 | Ghrelin receptor (GHS-R1a) | Peptides | Diagnostic and pharmacology studies; less selective, with cortisol and prolactin rises | Not stocked |
| MK-677 (ibutamoren) | Ghrelin receptor (GHS-R1a) | Oral small molecule | Several human trials, including a year-long study; never licensed | Dexterz Labs MK-677 |
| CJC-1295 | GHRH receptor | Lyophilised peptide | Pharmacology studies of the DAC version | CJC-1295 + Ipamorelin 10mg |
| Sermorelin | GHRH receptor | Lyophilised peptide | Formerly licensed in the US as Geref | Sermorelin 5mg |
Ipamorelin, the older GHRPs and MK-677 all act on the ghrelin receptor; CJC-1295 and sermorelin act on the GHRH receptor. Ipamorelin's place in the group is its selectivity: the comparison work showed growth hormone release without the cortisol and prolactin effects of GHRP-6 and GHRP-2.
Ipamorelin on its own or with CJC-1295
Ipamorelin is most often discussed alongside CJC-1295 because the two act on separate pituitary pathways, the ghrelin receptor and the GHRH receptor, and the growth hormone research literature often studies one compound from each pathway. No published human study tests the two together; the pairing is a research-market convention. The CJC-1295 and Ipamorelin guide covers the blend, the DAC question and the evidence for each peptide.
Stability, storage and handling
Ipamorelin is supplied lyophilised in a sealed vial, which tolerates transit at ambient temperature. On arrival, store the vial at -20C, protected from light, and keep it sealed until use. Reconstituted solutions degrade over days to weeks. The certificate should show HPLC purity and a mass spectrometry identity consistent with a molecular weight of about 712 g/mol.
Legal status in the UK, 2026
Ipamorelin is not a controlled substance under the Misuse of Drugs Act 1971. It has no marketing authorisation in the UK or anywhere else, so it cannot be sold or advertised for human use in the UK, where the MHRA would treat it as an unlicensed medicine. It is supplied strictly for laboratory research. In sport it is prohibited at all times under section S2 of the WADA Prohibited List, which names it among the growth hormone secretagogues.
What to check before buying
Milligram content per vial, HPLC purity, mass spectrometry identity, a batch number that matches the certificate, and UK dispatch. Every Origin Peptides batch is independently tested and its certificate of analysis is published on the product page and the Lab Testing page.
Frequently asked questions
What is ipamorelin?
A synthetic five amino acid peptide that acts on the ghrelin receptor in the pituitary and releases growth hormone. It was developed by Novo Nordisk in the 1990s and has never been licensed as a medicine.
Is ipamorelin the same as CJC-1295?
No. Ipamorelin acts on the ghrelin receptor; CJC-1295 is a GHRH analogue that acts on the GHRH receptor. They are sold together in a blend because they work through separate pathways.
How is ipamorelin different from GHRP-6?
Both act on the ghrelin receptor, but in the original comparison work ipamorelin released growth hormone without the rises in ACTH, cortisol and prolactin seen with GHRP-6 and GHRP-2.
How does ipamorelin compare with MK-677?
Same receptor. MK-677 is an oral small molecule with a long half-life and a larger human trial record; ipamorelin is a peptide with a short half-life of about two hours.
Is ipamorelin legal in the UK?
Legal to buy and possess as a research compound; not lawful to sell or advertise for human use. It is prohibited at all times in sport under WADA section S2.
Can you buy ipamorelin in the UK?
Yes, as a research peptide. Our Ipamorelin 5mg vial and CJC-1295 + Ipamorelin 10mg blend are stocked and dispatched from the UK.
Has ipamorelin been tested in humans?
Yes, in a pharmacokinetic study in healthy volunteers and a phase II trial in post-operative ileus, which did not meet its endpoint. There are no published human trials for body composition or ageing.
Key references
Raun K, Hansen BS, Johansen NL, et al. Ipamorelin, the first selective growth hormone secretagogue. European Journal of Endocrinology. 1998;139(5):552-561. Gobburu JV, Agersø H, Jusko WJ, Ynddal L. Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers. Pharmaceutical Research. 1999;16(9):1412-1416. Svensson J, Lall S, Dickson SL, et al. The GH secretagogues ipamorelin and GH-releasing peptide-6 increase bone mineral content in adult female rats. Journal of Endocrinology. 2000;165(3):569-577. Beck DE, Sweeney WB, McCarter MD; Ipamorelin 201 Study Group. Prospective, randomized, controlled, proof-of-concept study of the ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients. International Journal of Colorectal Disease. 2014;29(12):1527-1534. World Anti-Doping Agency. Prohibited List 2026, section S2.
Related guides
- CJC-1295 and Ipamorelin research guide
- Sermorelin research guide
- Tesamorelin research guide
- MK-677 (Ibutamoren): the research guide
- How to read a certificate of analysis
Research products: Origin Peptides Ipamorelin 5mg · CJC-1295 + Ipamorelin 10mg · Sermorelin 5mg · Full Origin Peptides range · Lab Testing