Ipamorelin is a synthetic pentapeptide from the group of growth hormone secretagogues (GHS). These are substances that bind to the receptor on which the body’s own peptide ghrelin also acts. The Danish company Novo Nordisk first described ipamorelin in 1998 [1]. It has never been authorised as a medicine: the European Medicines Agency (EMA) has no record of an authorisation or application [4], and it has not been approved in the United States either. On the research market, ipamorelin is also sold in combination with CJC-1295 (no DAC), an analogue of growth hormone-releasing hormone (GHRH).
Two routes to growth hormone
The pituitary gland releases growth hormone (GH) in pulses. That release is regulated through, among other things, two receptors. The first is the GHRH receptor, on which GHRH, a hormone from the hypothalamus, acts. The second is the ghrelin receptor, also called the GHS receptor or GHS-R1a in the literature.
Synthetic substances that act on that second receptor are called growth hormone secretagogues. They include the older growth hormone-releasing peptides (GHRPs), such as GHRP-1, GHRP-2 and GHRP-6. Ipamorelin emerged from that line of research. When it was developed, ghrelin itself had not yet been discovered, so the researchers referred to a ‘GHRP-like receptor’ [1].
Ipamorelin and CJC-1295 therefore act on different receptors within the same hormonal axis: ipamorelin on the ghrelin receptor, CJC-1295 on the GHRH receptor.
Structure and development of ipamorelin
| Feature | Ipamorelin |
|---|---|
| Substance class | synthetic pentapeptide, growth hormone secretagogue (GHS) |
| Sequence | Aib-His-D-2-Nal-D-Phe-Lys-NH2 |
| Notable features | two non-natural building blocks (Aib and 2-naphthylalanine), two D-amino acids and an amide at the end of the chain |
| Molecular formula | C38H49N9O5 (PubChem CID 9831659) |
| Molar mass | 711.9 g/mol |
| Developer | Novo Nordisk, Denmark (published 1998) |
Ipamorelin came out of a large chemistry programme. The researchers made a series of compounds derived from GHRP-1, but without its central Ala-Trp unit [1]. In experiments with rat pituitary cells, rats and pigs, ipamorelin acted through the same receptor as GHRP-6.
In pigs, the researchers saw no clear rise in the stress hormones ACTH or cortisol with ipamorelin, whereas they did with GHRP-6 and GHRP-2. That is why they called ipamorelin ‘the first selective growth hormone secretagogue’ [1]. This is a 1998 animal-research finding, not a property established for use in humans.
Ipamorelin was later studied clinically. A randomised, placebo-controlled phase 2 study (ClinicalTrials.gov NCT00672074) looked at adults after bowel surgery. The research question was delayed bowel function after surgery (postoperative ileus). On the main endpoints, the researchers found no significant differences from placebo [2]. A marketing authorisation never followed.
CJC-1295 and the ‘no DAC’ label
CJC-1295 is a GHRH analogue. It is derived from hGRF(1-29), the first 29 amino acids of human GHRH. The Canadian company ConjuChem described it in 2005 [3]. In CJC-1295, four amino acids of that chain have been replaced. In addition, the molecule carries an extra lysine at the end with a reactive group (a maleimide derivative). This ‘drug affinity complex’ (DAC), as the developer called it, lets the peptide attach to albumin in the blood. In the original rat studies, CJC-1295 therefore remained present in plasma much longer than hGRF(1-29) [3].
On the research market, ‘CJC-1295 no DAC’ refers to the 29-amino-acid chain with the same four replacements, but without the reactive group. This variant is also known as ‘modified GRF (1-29)’. It is therefore a different molecule from the CJC-1295 in the original publication, with a lower mass. So check on the certificate of analysis which variant was measured.
Regulation and anti-doping status
European Union and United States. Ipamorelin and CJC-1295 appear neither in the EMA’s medicines overview, which also lists withdrawn applications [4], nor in the FDA’s US drug database. Neither is authorised as a medicine in the EU or the US.
Sport. On the 2026 Prohibited List of the World Anti-Doping Agency (WADA), both substances are named in class S2.2.4, growth hormone releasing factors. CJC-1295 appears under ‘GHRH and its analogues’, ipamorelin under ‘growth hormone secretagogues’ [5]. Substances in class S2 are prohibited for athletes at all times, in and out of competition. Because sports federations and national anti-doping organisations apply this list, the combination of ipamorelin and CJC-1295 counts as a doping substance in organised sport. In some countries, doping substances are also covered by national legislation that applies outside sport; the rules differ by country.
Ipamorelin and the combination from Clean Peptides are research materials (research use only). They are not intended for use in humans or animals.
Analysis and storage
- Identity. Mass spectrometry (MS) shows whether the measured mass matches the expected structure. For ipamorelin that is 711.9 g/mol. In the combination, each peptide should show its own peak and mass, which also reveals whether CJC-1295 was measured with or without the DAC group.
- Purity. HPLC shows which share of the signal belongs to the main peak. For a combination, purity can be stated per component or for the whole; these are not the same. See How to read a certificate of analysis (COA).
- Storage. As freeze-dried powder: dry, cool and dark. See Storing peptides.
Every Clean Peptides vial has a batch number on the label. Record it with every experiment.
Products and further reading
Products
Ipamorelin 5 mg is supplied as freeze-dried powder in a vial. The combination is listed as ipamorelin 5 mg + CJC-1295 (no DAC) 5 mg. Another GHRH analogue is tesamorelin 10 mg. Solvent for the lab: bacteriostatic water 3 ml or 10 ml.
Further reading
- What is tesamorelin? The GHRH analogue explained
- What are peptides? Key terms explained
- How to read a certificate of analysis (COA)
- Knowledge base: peptides and research materials explained
Sources
- Raun K, Hansen BS, Johansen NL, et al. Ipamorelin, the first selective growth hormone secretagogue. European Journal of Endocrinology 1998;139(5):552–561. doi:10.1530/eje.0.1390552
- 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. doi:10.1007/s00384-014-2030-8
- Jetté L, Léger R, Thibaudeau K, et al. Human growth hormone-releasing factor (hGRF)1-29-albumin bioconjugates activate the GRF receptor on the anterior pituitary in rats: identification of CJC-1295 as a long-lasting GRF analog. Endocrinology 2005;146(7):3052–3058. doi:10.1210/en.2004-1286
- European Medicines Agency. Download medicine data, medicines overview including withdrawn applications (accessed 6 October 2026)
- World Anti-Doping Agency. Prohibited List 2026, class S2.2.4 (accessed 6 October 2026)
For laboratory research only. Clean Peptides products are not intended for use in humans or animals. This article provides general information and is not medical advice.
