This is a working overview of pentapeptide, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-06-03. Anything still debated is marked as such rather than presented as settled.
Selectivity distinguishes ipamorelin from first-generation secretagogues such as GHRP-6. At doses that reliably raise growth hormone, it shows little stimulation of adrenocorticotropic hormone or cortisol release in animal models, and it does not markedly raise prolactin or appetite. Binding at GHS-R1a on pituitary somatotrophs triggers calcium influx and pulsatile growth hormone secretion. Because the compound mimics the natural ghrelin signal, the release pattern tends to follow the body's own rhythm rather than producing a sustained elevation.
Most published work on ipamorelin comes from rodent studies and small early-phase human trials. Subcutaneous and intravenous routes have been used, while oral delivery is limited by poor absorption and rapid breakdown in the gut. The reported plasma half-life is short, on the order of two hours, and varies with species and assay method. Whether chronic use produces meaningful clinical benefit remains unresolved, and long-term safety data in humans are sparse. No major regulatory agency has approved the compound as a therapeutic drug.
Ipamorelin is a synthetic pentapeptide that belongs to the growth hormone secretagogue family. Its sequence is Aib-His-D-2-Nal-D-Phe-Lys-NH2, incorporating two non-natural residues that resist enzymatic breakdown. Researchers at Novo Nordisk described the compound in the 1990s while searching for agents that release growth hormone with fewer side effects than earlier secretagogues. The molecule acts as an agonist at the ghrelin receptor, also called GHS-R1a, which is expressed in the pituitary and in several peripheral tissues.
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 | Includes two non-natural residues |
| Molecular weight | About 711.9 g/mol | Confirmed by mass spectrometry |
| Appearance | White to off-white powder | Typical lyophilized form |
| Receptor target | GHS-R1a | Ghrelin receptor agonist |
| Plasma half-life | Roughly 2 hours | Varies by species and assay |
Mass spectrometry confirms identity and reveals structural deviations that chromatography alone can miss. Positive-mode electrospray ionisation generally yields multiply charged ions whose deconvoluted mass is checked against the theoretical value. Amino acid analysis, and enzymatic digestion with subsequent fragment mapping, provide independent confirmation of sequence and of the terminal amide. Analysts take care to separate the target from deletion sequences, which may differ by one residue and therefore by only a small mass increment.
The lyophilised solid is normally held at -20 °C or colder, shielded from light and moisture. Stability in that state is measured in years, although shelf life depends on residual water content and the container seal. Once dissolved, the peptide is more fragile: aqueous solutions are commonly kept at 2-8 °C and used within days to weeks, and repeated freeze-thaw cycling is avoided. Strongly acidic or basic conditions accelerate hydrolysis, and prolonged exposure to them can strip the terminal amide.
Purity assessment for this peptide relies mainly on reversed-phase high-performance liquid chromatography. A C18 column with a water-acetonitrile gradient containing trifluoroacetic acid separates the target from truncated sequences and oxidation products. Detection near 214 nm exploits the amide backbone, while the aromatic side chains allow additional monitoring close to 280 nm. Reported purity values depend on the method, so a certificate of analysis carries weight only when gradient, column and integration parameters are given.
Reversed-phase high-performance liquid chromatography is the standard method for purity assessment, most often on a C18 column with a water and acetonitrile gradient and trifluoroacetic acid or formic acid as an ion-pairing agent. Mass spectrometry by electrospray or matrix-assisted laser desorption confirms the expected mass and reveals truncated or modified sequences. Amino acid analysis and sequencing provide orthogonal structural evidence. Typical impurities include deletion sequences, oxidized products, and dimeric species. Detection wavelength, usually 214 or 220 nanometers, should be reported because response factors differ between peptides.
Purity is normally reported as a percentage of total peak area, a figure that does not account for water content, residual solvents, or counterions. Trifluoroacetate and acetate are the most frequent counterions in lyophilized peptides, and they shift the true peptide content away from the mass of the powder. A separate quantitative assay is therefore needed to state content accurately. Certificates of analysis often omit these details, which makes batch-to-batch comparison difficult and limits conclusions drawn when results from different suppliers are compared.
Lyophilized material is generally held at minus twenty degrees Celsius or lower, protected from moisture and light. Repeated excursions to room temperature cause condensation inside the vial and gradual moisture uptake, both of which shorten shelf life. Containers should be allowed to equilibrate before opening so that water does not condense on the solid. Dividing a batch into single-use aliquots reduces freeze-thaw cycling. Solid peptide handled this way is usually considered stable for months to years, while the same material in solution degrades on a much shorter timescale.
Signal transduction begins when the peptide binds GHSR-1a on pituitary somatotrophs. The receptor couples to Gq/11 proteins, activating phospholipase C, which cleaves phosphatidylinositol bisphosphate into inositol trisphosphate and diacylglycerol. Inositol trisphosphate releases calcium from intracellular stores, and the resulting rise in cytosolic calcium drives growth hormone vesicle fusion. Concurrent Gs coupling and cyclic AMP elevation have also been reported, and the relative contribution of each arm to the overall secretory response is not fully settled.
Structural features distinguish the molecule from earlier secretagogues. An alpha-aminoisobutyric acid residue near the N-terminus and a D-naphthylalanine substitution increase receptor affinity, while C-terminal amidation improves resistance to exopeptidases. These modifications are associated with reduced stimulation of appetite and of the hypothalamic-pituitary-adrenal axis compared with hexarelin or growth hormone releasing peptide-6. Whether the same profile applies at every dose level studied is a matter of ongoing investigation rather than settled consensus.
Ciliary neurotrophic factor is a protein that in humans is encoded by the CNTF gene. The protein encoded by this gene is a polypeptide hormone and neurotrophic factor whose actions have mainly been studied in the nervous system where it promotes neurotransmitter synthesis and neurite outgrowth in certain neural populations including astrocytes. It is a hypothalamic neuropeptide that is a potent survival factor for neurons and oligodendrocytes and may be relevant in reducing tissue destruction during inflammatory attacks. A mutation in this gene, which results in aberrant splicing, leads to ciliary neurotrophic factor deficiency, but this phenotype is not causally related to neurologic disease. In addition to the predominant monocistronic transcript originating from this locus, the gene is also cotranscribed with the upstream ZFP91 gene. Cotranscription from the two loci results in a transcript that contains a complete coding region for the zinc finger protein but lacks a complete coding region for ciliary neurotrophic factor. CNTF has also been shown to be expressed by cells on the bone surface, and to reduce the activity of bone-forming cells (osteoblasts).
In 1962, Meurgues' work came to the attention of the botanist Roger Heim. He tasked her with setting up a scientific laboratory in the Muséum national d'histoire naturelle, dedicated to new methods of conservation and presentation of natural history museum collections. This included conservation techniques such as freeze-drying, and resinous injections, the scientific preservation of colours and pigments, as well as improving the interpretation of exhibitions and displays. She organised and directed the laboratory whilst studying for a Diplôme d'études approfondies (Master's degree) in zoology on Calliphoridae, (types of flies) which she completed in 1973. She was promoted to become the museum's assistant professor, and went on collecting expeditions to Kurdistan, Afghanistan, Kashmir, China, Morocco amongst others. Meurgues organised a number temporary exhibitions including: Les pigments végétaux (Vegetable Pigments) in 1963, Orchidées et plantes épiphytes (Orchids and epiphytic plants) in 1966, Météorites, messagères du cosmos (Meteorites, messengers of the cosmos) in 1968, La Nature au microscope électronique (Nature under an electron microscope) in 1971, Le Sahara avant le désert (The Sahara before the desert) in 1974, Les plus beaux coquillages du monde (The most beautiful shells of the world) in 1975, Histoire naturelle de la sexualité (Natural history of sexuality) in 1977 with André Langaney, a leading French science communicator.
Genetically modified organism History of biotechnology An Asilomar Moment Archived 10 July 2013 at the Wayback Machine Original Asilomar Genetics Guidelines “Asilomar Conference.” Provides another summary of the Asilomar Conference. The Basics of Recombinant DNA provides an introduction to the science behind recombinant DNA. The Recombinant DNA Debate Archived 31 March 2007 at the Wayback Machine provides more details about the history of the debate surrounding the use of recombinant DNA technology. “Paul Berg: The 1980 Nobel Prize in Chemistry – Autobiography.” Provides an autobiography about Paul Berg. Science History Institute: The story of the 1975 Asilomar Conference on Recombinant DNA
Sources: en.wikipedia.org
The mean daily doses of metformin at week 24 were 1,699 and 1,868 mg for the gemigliptin/metformin group and the metformin group, respectively. Mean change in HbA1c from baseline was –2.06% for gemigliptin/metformin group versus –1.24% for the gemigliptin group and –1.47% for the metformin group, respectively (P<0.0001 for all comparisons of combination therapy vs. monotherapy). The differences in proportions achieving an HbA1c <7% or <6.5% were also statistically significant (P<0.0001) between the combination therapy and the respective monotherapy groups. Add-on to metformin A 24-week, multinational, randomized, blinded, active-controlled study (study identifier: LG-DPCL006; ClinicalTrials.gov registration number: NCT01602003) was designed to assess the efficacy and safety of gemigliptin 50 mg compared to the active control (sitagliptin) added to ongoing metformin therapy in patients with T2DM inadequately controlled with metformin alone (HbA1c, 7% to 11%). After 24 weeks, the reduction from baseline for HbA1c was 0.81% for gemigliptin 25 mg twice a day (bid) and 0.77% for gemigliptin 50 mg qd, and the differences in the least square mean changes from baseline between groups (each group of gemigliptin-sitagliptin group) were −0.011% in gemigliptin 25 mg bid and 0.004% in gemigliptin 50 mg qd. The proportion of patients achieving an HbA1c <7% at week 24 (gemigliptin 25 mg bid group, 50%; gemigliptin 50 mg qd group, 54.07%) was comparable to the results with sitagliptin 100 mg qd (48.87%).
=== Biochemistry === In solution, detergents help solubilize a variety of chemical species by dissociating aggregates and unfolding proteins. Popular surfactants in the biochemistry laboratory are sodium lauryl sulfate (SDS) and cetyl trimethylammonium bromide (CTAB). Detergents are key reagents to extract protein by lysis of the cells and tissues: they disorganize the membrane's lipid bilayer (SDS, Triton X-100, X-114, CHAPS, DOC, and NP-40), and solubilize proteins. Milder detergents such as octyl thioglucoside, octyl glucoside or dodecyl maltoside are used to solubilize membrane proteins such as enzymes and receptors without denaturing them. Non-solubilized material is harvested by centrifugation or other means. For electrophoresis, for example, proteins are classically treated with SDS to denature the native tertiary and quaternary structures, allowing the separation of proteins according to their molecular weight. Detergents have also been used to decellularise organs. This process maintains a matrix of proteins that preserves the structure of the organ and often the microvascular network. The process has been successfully used to prepare organs such as the liver and heart for transplant in rats. Pulmonary surfactants are also naturally secreted by type II cells of the lung alveoli in mammals.
Potassium can be detected by a traditional flame test. Its compounds emit a lilac color with a peak emission wavelength of 766.5 nanometers. Potassium can be quantified by spectroscopic methods, including flame photometry and X-ray fluorescence. Traditional gravimetric analysis is still employed in the fertilizer industry (the dominant use of potassium). The main analytical reagent is hexachloroplatinic acid. Treatment of a solution containing K+ ions with an excess of this platinum compound quantitatively precipitates of potassium hexachloroplatinate, which is easily weighed and is non-hygroscopic:
== Bibliography == Pirie, N. W (1971). "Leaf protein:its agronomy, preparation, quality and use". IBP Handbook. Vol. 20. Blackwell Scientific Publications. Pirie, N. W (1975). "Leaf protein: a beneficiary of tribulations". Nature. 253 (5489): 239–241. Bibcode:1975Natur.253..239P. doi:10.1038/253239a0. S2CID 4196894.
Sources: en.wikipedia.org
The peptide is Aib-His-D-2-Nal-D-Phe-Lys-NH2. Two of its residues are non-natural, which slows enzymatic degradation. The C-terminal amide is common among bioactive peptides.
It binds the same ghrelin receptor but with greater selectivity in functional assays. Preclinical work reports less cortisol and prolactin stimulation at growth-hormone-releasing doses. Those differences are relative, not absolute, and depend on dose and model.
No major regulatory authority has approved it for human therapeutic use. It is sold as a research chemical for laboratory investigation. Clinical status varies by country and is subject to change.
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.