GHS-R1a raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-12-05. Anything still debated is marked as such rather than presented as settled.
At the molecular level, ipamorelin acts as an agonist at the growth hormone secretagogue receptor type 1a, the same G protein-coupled receptor that binds ghrelin. Receptor activation couples to Gq/11 signaling, raising intracellular calcium through inositol trisphosphate and diacylglycerol, which in turn promotes exocytosis of growth hormone from pituitary somatotroph cells. Ipamorelin binds this receptor with high affinity and shows weak activity at other secretagogue-related targets in vitro. Its action requires the intact receptor and is not reversed by growth hormone-releasing hormone antagonists.
Compared with earlier growth hormone secretagogues such as GHRP-6 and hexarelin, ipamorelin has been reported to produce less stimulation of adrenocorticotropic hormone, cortisol, and prolactin in animal and early human studies. This selectivity is usually attributed to differences in receptor subtype interactions and to the tissue distribution of the receptor. Effects on appetite appear weaker than those of ghrelin itself, although the supporting evidence base is small. Whether these differences produce a distinct clinical profile remains an open question, since controlled human trials are limited.
Ipamorelin is a synthetic pentapeptide first described in the 1990s by researchers at Novo Nordisk during a program to develop selective growth hormone secretagogues. Its sequence is Aib-His-D-2-Nal-D-Phe-Lys-NH2, incorporating two non-natural residues, alpha-aminoisobutyric acid and D-2-naphthylalanine. The C-terminus is amidated, and the material is supplied as a white lyophilized powder. The molecular formula is C38H49N9O5 and the monoisotopic mass is approximately 711.85 daltons. The short chain and modified residues give it greater resistance to enzymatic degradation than many larger peptide hormones.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C38H49N9O5 | Pentapeptide with amidated C-terminus |
| Molecular weight | 711.85 g/mol | Monoisotopic mass |
| Primary receptor | GHS-R1a | Ghrelin receptor, Gq/11 coupled |
| Peptide class | Synthetic pentapeptide | Contains two non-natural residues |
| Reported selectivity | Lower cortisol and prolactin effect | Observed in animal and early human work |
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.
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.
Lyophilized material is generally stored frozen and protected from light and moisture. Typical recommendations place dry powder at temperatures well below freezing, while reconstituted solutions are kept cold and used within a defined window. Repeated freezing and thawing should be avoided because it can promote aggregation and loss of material. The choice of solvent matters as well; compatibility with the intended diluent should be checked before preparation. These handling practices aim to preserve both the quantity and the integrity of the peptide.
Verification of identity and purity relies on analytical methods used across peptide chemistry. Reverse-phase high-performance liquid chromatography separates components by hydrophobicity and provides a purity estimate. Mass spectrometry confirms molecular mass and helps detect modifications. Together these techniques give complementary information about whether a sample matches its expected structure. Results depend on method parameters and reference standards, so reported purity values are meaningful only when the analytical conditions are stated. Consistency between laboratories requires comparable protocols and well-characterized reference materials.
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.
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.
Label transfer can be used for screening or confirmation of protein interactions and can provide information about the interface where the interaction takes place. Label transfer can also detect weak or transient interactions that are difficult to capture using other in vitro detection strategies. In a label transfer reaction, a known protein is tagged with a detectable label. The label is then passed to an interacting protein, which can then be identified by the presence of the label. Phage display is used for the high-throughput screening of protein interactions. In-vivo crosslinking of protein complexes using photo-reactive amino acid analogs was introduced in 2005 by researchers from the Max Planck Institute In this method, cells are grown with photoreactive diazirine analogs to leucine and methionine, which are incorporated into proteins. Upon exposure to ultraviolet light, the diazirines are activated and bind to interacting proteins that are within a few angstroms of the photo-reactive amino acid analog. Tandem affinity purification (TAP) method allows high throughput identification of protein interactions. In contrast to yeast two-hybrid approach the accuracy of the method can be compared to those of small-scale experiments and the interactions are detected within the correct cellular environment as by co-immunoprecipitation. However, the TAP tag method requires two successive steps of protein purification and consequently it can not readily detect transient protein–protein interactions. Recent genome-wide TAP experiments were performed by Krogan et al.
== Cultivation == In Siddha medicine, it is known as kostum. It is being cultivated in Kashmir and the Himalayan regions for its root. It is related to the gingers and was originally part of the family Zingiberaceae. The plant grows very quickly. Propagation is by stem cutting. It needs sunshine but it also grows in slightly shady areas. It is cultivated in India for its use in traditional medicine and elsewhere as an ornamental.
=== Family record book (1877) === The loss of Parisian civil records largely influenced the creation of the family record book in 1877, introduced by a circular from Jules Simon, President of the Council and Minister of the Interior. The circular explicitly referenced the Commune’s destruction, stating that “family record books will serve as a third deposit of civil records entrusted to individuals and will provide valuable information should registers be destroyed.” The law of April 5, 1884, concerning municipal organization, required town halls to budget for the costs of family record books.
Sources: en.wikipedia.org
== Mass spectra == In positive ion mode, DART produces predominantly protonated molecules [M+H]+ and in negative-ion mode deprotonated molecules [M-H]−. Both negative and positive modes of DART provides relatively simple mass spectra. Depending on the type of analyte, other species may be formed, such as multiple charged adducts. DART is categorized as a soft ionization technique. Fragmentation can be rarely observed for some molecules.
== History == Flurpiridaz F-18 is a fluorine 18-labeled agent, developed by Lantheus Medical Imaging for the diagnosis of coronary artery disease. The efficacy and safety of flurpiridaz (18F) was evaluated in two prospective, multicenter, open-label clinical studies in adults with either suspected CAD (Study 1: NCT03354273) or known or suspected CAD (Study 2: NCT01347710). Study 1 evaluated the sensitivity (ability to designate an imaged patient with disease as positive) and specificity (ability to designate an imaged patient without disease as negative) of flurpiridaz (18F) for the detection of significant CAD in subjects with suspected CAD, who were scheduled for invasive coronary angiography (ICA). Across three flurpiridaz (18F) imaging readers, estimates of sensitivity ranged from 74% to 89% and estimates of specificity ranged from 53% to 70% for CAD defined as at least 50% narrowing of an artery. Study 2 evaluated the sensitivity and specificity of flurpiridaz (18F) for the detection of significant CAD in subjects with known or suspected CAD, who had ICA without intervention within 60 days prior to imaging or were scheduled for ICA. Across three flurpiridaz (18F) imaging readers, estimates of sensitivity ranged from 63% to 77% and estimates of specificity ranged from 66% to 86% for CAD defined as at least 50% narrowing of an artery.
Some plants such as willow trees and poplars have been found to clean both lead and cadmium from soil. Typical background concentrations of cadmium do not exceed 5 ng/m3 in the atmosphere; 2 mg/kg in soil; 1 μg/L in freshwater and 50 ng/L in seawater. Concentrations of cadmium above 10 μg/L may be stable in water having low total solute concentrations and pH and can be difficult to remove by conventional water treatment processes.
Sources: en.wikipedia.org
It is a synthetic pentapeptide belonging to the growth hormone secretagogue family. Its principal characterized target is the ghrelin receptor, also called GHS-R1a. The molecule contains non-natural amino acids and an amidated C-terminus.
Both act at the same G protein-coupled receptor, but ipamorelin is a short synthetic peptide with modified residues rather than the natural 28-amino-acid hormone. Reports describe weaker effects on appetite and on cortisol or prolactin release than those seen with ghrelin. Its resistance to enzymatic breakdown also differs from that of the natural ligand.
Receptor binding and downstream calcium signaling are well characterized in cell-based systems. Effects measured in whole organisms are less consistent across studies and species. The extent to which selective receptor behavior drives the observed hormonal profile is still debated.
It is reported as the percentage of total peak area in a reversed-phase chromatogram. That number does not reflect water content, residual solvents, or counterions. The actual peptide content is therefore lower than the stated purity figure suggests.