pentapeptide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
The compound was developed at Novo Nordisk during the 1990s as part of a programme seeking secretagogues with improved selectivity. It was described in the peer-reviewed literature in 1998 alongside related pentapeptides from the same series. Investigators advanced it because it raised growth hormone output in animal models while leaving other pituitary hormones comparatively unaffected. The development code NNC 26-0161 appears in earlier reports, and ipamorelin later became the common designation in published work.
Selectivity is the property most often attached to this peptide. Published animal and early human studies record increases in growth hormone release after administration, with adrenocorticotropic hormone and cortisol responses remaining small by comparison. Effects on appetite-related pathways also appear weaker than those reported for several earlier secretagogues. Reviews that compare members of the growth hormone secretagogue family cite these findings frequently, though the receptor-level explanation for the selectivity continues to be debated rather than settled.
Ipamorelin is a synthetic pentapeptide classified as a growth hormone secretagogue. Its sequence, Aib-His-D-2-Nal-D-Phe-Lys-NH2, combines three non-proteinogenic residues with a C-terminal amide. The N-terminal aminoisobutyric acid unit and the two aromatic D-amino acids distinguish it from peptides assembled only from standard L-amino acids. Its formula is C38H49N9O5, corresponding to an average mass near 711.9 Da. At neutral pH the molecule carries a net positive charge, a property that shapes its behaviour in chromatographic and electrophoretic systems.
Ipamorelin is a synthetic pentapeptide that belongs to the growth hormone secretagogue class of compounds. Its sequence is Aib-His-D-2-Nal-D-Phe-Lys-NH2, a structure that differs from natural ghrelin in length and in the presence of non-natural amino acid residues. Early laboratory work described it as a comparatively selective agent that stimulates growth hormone release with limited effect on other pituitary hormones. The compound is supplied as a lyophilized solid for research use and has no identified natural source in the body.
Activity is mediated mainly through the growth hormone secretagogue receptor, now generally called the ghrelin receptor or GHS-R1a. Binding at this G-protein-coupled receptor triggers phospholipase C signaling, calcium mobilization, and release of growth hormone from pituitary somatotrophs. Reports describe less pronounced stimulation of adrenocorticotropic hormone and prolactin compared with earlier secretagogues such as hexarelin or GHRP-6. Selectivity figures vary between assay systems, so the degree of separation from other secretagogues is an area of ongoing comparison rather than a fixed constant.
In animal and early human studies, ipamorelin produces pulsatile growth hormone release and a secondary rise in insulin-like growth factor 1. The magnitude and duration of that rise depend on route, sampling schedule, and the baseline endocrine state of the subject. Whether repeated exposure alters the response over time is not firmly settled, since some reports describe stable pulsatility while others note attenuation. Most published data come from small samples, which limits the strength of any general claim about long-term behavior.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C38H49N9O5 | Pentapeptide with C-terminal amide |
| Average mass | Approximately 711.9 Da | Value derived from the formula |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility | Soluble in water and aqueous acetonitrile | Dissolution aided by acidic diluents |
| Common synonyms | Ipamorelin; NNC 26-0161 | Code name used in early reports |
Lyophilized ipamorelin powder is the form usually supplied for laboratory work. Kept dry, protected from light, and held at minus 20 degrees Celsius or below, it remains stable for extended periods, often measured in years. Once dissolved, the peptide degrades faster through hydrolysis, oxidation, and deamidation, so solutions are typically refrigerated and used within weeks. Repeated freeze-thaw cycles and exposure to alkaline conditions accelerate loss of the parent compound.
Reversed-phase high-performance liquid chromatography is the standard tool for assessing purity. Detection near 214 nanometers captures the peptide backbone, and the resulting chromatogram shows the main peak alongside related impurities. Electrospray ionization mass spectrometry confirms molecular mass and supports sequence verification. Common degradation products include oxidized residues, deamidated forms, and truncated fragments, each appearing as a distinct peak or shoulder in the trace.
Quality claims for research peptides vary widely across suppliers. A certificate of analysis should list purity by chromatography, the mass found by spectrometry, and the analytical conditions used. Independent testing at a third-party laboratory is a common way to check identity and purity, because documents alone cannot confirm what is inside a vial. Purity figures describe the proportion of the target peptide among detected species, and they say nothing about biological activity or sterility.
HGEGTFTSDV SSYLEGQAAK EFIAWLVKGR HGEGTFTSDV SSYLEGQAAK EFIAWLVKGR (2 copies of modified GLP-1, modifications underlined) DAHKSEVAHR FKDLGEENFK ALVLIAFAQY LQQCPFEDHV KLVNEVTEFA KTCVADESAE (albumin starts at the beginning of this line) NCDKSLHTLF GDKLCTVATL RETYGEMADC CAKQEPERNE CFLQHKDDNP NLPRLVRPEV DVMCTAFHDN EETFLKKYLY EIARRHPYFY APELLFFAKR YKAAFTECCQ AADKAACLLP KLDELRDEGK ASSAKQRLKC ASLQKFGERA FKAWAVARLS QRFPKAEFAE VSKLVTDLTK VHTECCHGDL LECADDRADL AKYICENQDS ISSKLKECCE KPLLEKSHCI AEVENDEMPA DLPSLAADFV ESKDVCKNYA EAKDVFLGMF LYEYARRHPD YSVVLLLRLA KTYETTLEKC CAAADPHECY AKVFDEFKPL VEEPQNLIKQ NCELFEQLGE YKFQNALLVR YTKKVPQVST PTLVEVSRNL GKVGSKCCKH PEAKRMPCAE DYLSVVLNQL CVLHEKTPVS DRVTKCCTES LVNRRPCFSA LEVDETYVPK EFNAETFTFH ADICTLSEKE RQIKKQTALV ELVKHKPKAT KEQLKAVMDD FAAFVEKCCK ADDKETCFAE EGKKLVAASQ AALGL
baiCD (NAD+-dependent-3-oxo-𝚫4-cholenoic acid oxidoreductase): Located directly downstream of baiB on the bai operon, baiCD functions to catalyze C4-C5 oxidation, creating a 3-dehydro-Δ4-cholic-acid-CoA intermediate. This enzyme performs a reduction that introduces a new double bond between C4-C5 in one of the bile acid’s aromatic rings. Along with baiA2, baiCD acts twice in the 7ɑ-dehydroxylation pathway, catalyzing the first and last two redox reactions. baiE (7-ɑ dehydratase): Located directly downstream of baiCD, the baiE gene codes for a 7-ɑ dehydratase enzyme that performs a diaxial trans elimination of water from the baiCD-produced bile acid intermediate. The mechanism for this transformation is not known, but previous research indicates that it is similar to that of the also elusive baiI, which may encode for 7-β dehydratase. baiE and baiI are believed to likely have similar mechanisms due to their homologous amino acid sequences and apparent stereospecificity as well. baiF (bile-acid CoA hydrolase): Immediately downstream of baiA2, baiF codes for a bile-acid CoA hydrolase that removes the CoA group from bile acid intermediates. One research study revealed that this removed CoA is transferred and conjugated to cholic acid. The baiF gene product resembles carnitine dehydratase in Escherichia coli, which is classified as a thioesterase. However, baiF does not resemble any known thioesterases, so some researchers propose that baiF encodes a novel family of thioesterases.
Caldwell, Donald and Richard Muller. The Luftwaffe over Germany – Defense of the Reich. St. Paul, Minnesota: Greenhill books, MBI Publishing, 2007. ISBN 978-185367-712-0. Carson, Leonard "Kit." Pursue & Destroy. Granada Hills, California: Sentry Books Inc., 1978. ISBN 0-913194-05-0. Carter, Dustin W. and Birch J. Matthews.Mustang: The Racing Thoroughbred. West Chester, Pennsylvania: Schiffer Publishing Company, 1992. ISBN 978-0-88740-391-0. Cleaver, Tom (April–July 1982). "Return of the Razorbacks". Air Enthusiast. No. 18. pp. 26–31. ISSN 0143-5450. Craven, Wesley; Cate, James (1949). The Army Air Forces in World War II, Volume Two: Europe, Torch to Pointblank, August 1942 to December 1943. Chicago: University of Chicago. Darling, Kev. P-51 Mustang (Combat Legend). Shrewsbury, UK: Airlife, 2002. ISBN 1-84037-357-1. Davis, Larry. P-51 Mustang. Carrollton, Texas: Squadron/Signal Publications, Inc., 1995. ISBN 0-89747-350-7. Dean, Francis H. America's Hundred Thousand. Atglen, Pennsylvania: Schiffer Publishing Ltd., 1997. ISBN 0-7643-0072-5. Delve, Ken. The Mustang Story. London: Cassell & Co., 1999. ISBN 1-85409-259-6. Delve, Ken. The Source Book of the RAF. Shrewsbury, Shropshire, UK: Airlife Publishing, 1994. ISBN 1-85310-451-5. Dienst, John and Dan Hagedorn. North American F-51 Mustangs in Latin American Air Force Service. London: Aerofax, 1985. ISBN 0-942548-33-7. Donald, David, ed. Encyclopedia of World Aircraft. Etobicoke, Ontario: Prospero, 1997. ISBN 1-85605-375-X. Dorr, Robert F. P-51 Mustang (Warbird History). St.
Sources: en.wikipedia.org
=== Discharge of potassium thiocyanate === In 2007, Merck settled Clean Water Act violations related to the discharge of potassium thiocyanate and resulting fish kills in the Wissahickon creek. In 2011, Merck paid a $1.5 million civil penalty to settle violations of federal environmental laws at its pharmaceutical manufacturing facilities in Riverside, Pennsylvania (in relation to use of methylene chloride) and West Point, Pennsylvania (in relation to discharge of potassium thiocyanate).
== References == This article incorporates material from the Citizendium article "Drugs banned from the Olympics", which is licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported License but not under the GFDL.
=== Class III: Cys-based PTPs === The third class of PTPs contains three cell cycle regulators, CDC25A, CDC25B and CDC25C, which dephosphorylate CDKs at their N-terminal, a reaction required to drive progression of the cell cycle. They are themselves regulated by phosphorylation and are degraded in response to DNA damage to prevent chromosomal abnormalities.
Sources: en.wikipedia.org
It is a synthetic five-amino-acid peptide that acts as a growth hormone secretagogue. Three of its residues are non-standard amino acids, and the chain ends in an amide rather than a free acid. The molecule is small enough that it can be characterised by routine peptide analytical techniques.
It has not received marketing approval as a medicine in the United States or the European Union. Supplied material is generally described and handled as a research chemical. Regulatory treatment varies by jurisdiction, and some countries restrict growth hormone secretagogues under sports or medicines legislation.
Earlier secretagogues were associated with broader hormonal responses, including measurable changes in cortisol and prolactin. Reports on this peptide describe a narrower profile in which growth hormone release is the most prominent effect. The observation is influential because it shapes how the compound is compared with other members of the same receptor family.
It is a synthetic pentapeptide in the growth hormone secretagogue family and acts as an agonist at the ghrelin receptor. It is handled as a laboratory research compound rather than a naturally occurring hormone.