The short version of GLP-1 analogue fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-04-29. Anything still debated is marked as such rather than presented as settled.
Semaglutide is a synthetic peptide analogue of glucagon-like peptide-1, a gut hormone released by intestinal L cells after food intake. The natural hormone acts on pancreatic and central receptors but is degraded within minutes by dipeptidyl peptidase-4 and other peptidases. Semaglutide belongs to the class of long-acting GLP-1 receptor agonists, a group distinguished by structural changes that slow breakdown and extend circulation time. Its development followed earlier short-acting analogues and reflects a general strategy in peptide drug design: preserve receptor activity while blocking proteolytic clearance.
Three structural changes define the molecule. At position 8 an alpha-aminoisobutyric acid residue replaces alanine, which blocks dipeptidyl peptidase-4 cleavage. At position 34 arginine replaces lysine, and at position 26 a lysine carries a C18 fatty diacid attached through a short linker. The fatty chain binds serum albumin, and this albumin association reduces renal filtration and enzymatic attack. The unchanged backbone retains the receptor contacts that produce signalling. The free base has the formula C187H291N45O59 and a molecular weight near 4114 daltons.
Semaglutide is a synthetic peptide analogue of glucagon-like peptide-1, a gut hormone released after nutrient intake. The molecule contains 31 amino acid residues and differs from the native sequence at several positions. A non-natural residue at position eight resists the enzyme that normally truncates the hormone, while a lysine-linked fatty diacid side chain promotes binding to serum albumin. These two modifications extend the circulating half-life from minutes to roughly one week. The peptide is produced by solid-phase synthesis followed by selective acylation, and its identity and purity are confirmed by spectrometric and chromatographic techniques.
The primary target is the GLP-1 receptor, a class B G protein-coupled receptor expressed on pancreatic beta cells, in the gut, and in several brain regions. Receptor activation raises intracellular cyclic AMP, which potentiates glucose-dependent insulin secretion and lowers glucagon release when blood glucose is elevated. Signalling in the hypothalamus and brainstem is associated with reduced appetite and slower gastric emptying. Because the insulinotropic effect depends on prevailing glucose levels, the hypoglycaemic risk of the peptide alone is described as low in most study settings. The relative contribution of peripheral and central actions remains an active research question.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C187H291N45O59 | free base, without counter-ion |
| Molecular weight | About 4114 Da | peptide backbone plus attached lipid chain |
| Plasma half-life | About 165 hours | supports once-weekly dosing in humans |
| Plasma protein binding | Greater than 99 percent | attributed mainly to serum albumin |
| Receptor target | GLP-1 receptor | Gs-coupled, raises intracellular cyclic AMP |
Storage at minus 20 degrees Celsius or lower in a desiccated container preserves the peptide for extended periods, while working solutions are commonly held at two to eight degrees Celsius for short intervals. Light exposure and repeated freeze-thaw cycles accelerate degradation, so dividing material into single-use aliquots is generally recommended. Adsorption to glass and plastic surfaces can lower the measured concentration of dilute solutions, particularly below one milligram per millilitre. The degradation routes most often reported for GLP-1 analogues are deamidation, methionine oxidation, and backbone hydrolysis. Relative rates under specific conditions are frequently described only for individual formulations.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 or 280 nanometres is widely used to assess purity and to resolve related impurities. Liquid chromatography coupled to mass spectrometry confirms identity through the protonated molecular ion and fragment ions formed in tandem experiments. Capillary electrophoresis and peptide mapping after enzymatic digestion supply complementary information on charge variants and modification sites. Circular dichroism and nuclear magnetic resonance can report on secondary structure in solution. Absolute quantification usually depends on an external standard, and reported purity depends on the detection wavelength and integration parameters chosen.
Lyophilized semaglutide is typically stored at temperatures between minus 20 and minus 80 degrees Celsius for long-term preservation. Short-term storage at 2 to 8 degrees Celsius is common for working aliquots. Repeated freeze-thaw cycles can degrade the peptide and are usually avoided. The molecule is hygroscopic in its solid form, so containers should remain sealed with desiccant. Solutions are less stable than powders and are generally prepared fresh. Light exposure is limited because aromatic residues can undergo photo-oxidation.
Semaglutide dissolves readily in water and in aqueous buffers near neutral pH. Solubility decreases near the isoelectric point, where net charge is minimal. Common laboratory solvents include phosphate-buffered saline and dilute ammonium bicarbonate. Strongly acidic or basic conditions may accelerate hydrolysis. Working concentrations are usually prepared by diluting a concentrated stock. Vial surfaces can adsorb small amounts of peptide at low concentrations, so carrier proteins or low-binding tubes are sometimes used.
Reverse-phase high-performance liquid chromatography is the standard method for purity assessment, separating the peptide from truncated or oxidized variants. Mass spectrometry confirms molecular mass and detects modifications, while ultraviolet absorbance near 280 nanometers supports concentration measurement through tryptophan and tyrosine residues. Circular dichroism can indicate secondary structure, though the peptide is largely helical in solution, and ion-exchange chromatography resolves charge variants. Purity values above 95 percent are typical for research-grade material. Stability studies track degradation over time under defined conditions.
=== 30 November === Ursula von der Leyen, president of the European Commission, suggested the creation of a UN court to investigate war crimes committed by Russia. Russia does not recognize the International Criminal Court, so the European Commission proposed two possible alternative ways to hold Russia accountable: either to create a court that would be set up by international treaties, or to create an international court with a number of judges from several countries. She estimated the war damage to Ukraine is about 600 billion Euros. She proposed a financial plan to help pay for this. She pointed out that the EU had frozen 300 billion Euros worth of Russian central bank reserves and 20 billion Euros worth of money belonging to Russian oligarchs, which she suggested should be invested. The investments could be given to Ukraine when sanctions are lifted. The original statement by Ursula von der Leyen included a claim that 100,000 Ukrainian soldiers and 20,000 Ukrainian civilians have been killed so far in the war. This angered Ukrainian military officials, who said that the death toll was classified information. In response, the European Commission edited the video of von der Leyen's speech to remove this information. Official publications of the text of the speech were also edited to omit the numbers.
Activated platelets have the ability to bind glycoproteins and glycolipids (P-selectin ligands such as PSGL-1) on the surface of cancer cells to form a physical barrier that protects the cancer cell from natural killer cell-mediated lysis in the bloodstream. Furthermore, activated platelets promote the adhesion of cancer cells to activated endothelial cells lining blood vessels using adhesion molecules present on platelets. P-selectin ligands on the surface of cancer cells remain to be elucidated and may serve as potential biomarkers for disease progression in cancer.
== Pharmacokinetics == The chemical is poorly soluble, and has only very limited penetration through intact skin. However, contact with body fluids produces free sulfadiazine which can then be systemically absorbed and distributed; it undergoes glucuronidation in the liver and is also excreted unaltered in urine. Only when applied to large-area (especially second- and third-degree) burns or other lesions is absorption into the body a problem.
Sources: en.wikipedia.org
== Personal life == In 1971, Parsons married Gretchen Burrell (née Gretchen Lisl Berrill) at his stepfather's New Orleans estate. Parsons and Burrell went to England, where they visited their friend Ric Grech. With the help of Grech and his friend Hank Wangford, Parsons stopped using heroin. In the summer of 1973, Parsons' Topanga Canyon home burned to the ground, the result of a stray cigarette. Nearly all of his possessions were destroyed with the exception of a guitar and a prized Jaguar. The fire proved to be the last straw in the relationship between Burrell and Parsons, who moved into a spare room in Kaufman's house. Parsons rekindled his relationship with Margaret Fisher, a high school sweetheart from Waycross. Parsons had one child, born to Nancy Ross in 1967, Polly Parsons.
Specific vitamin A supplementation is particularly important for preventing further damage to the liver and skin. Ready-to-use therapeutic foods (RUTFs) and F-75 and F-100 milks were created to provide appropriate nutrition and caloric intake to those experiencing malnutrition. F-75 milk would be ideal when trying to reintroduce food into a malnourished person, and F-100 milk would be used to aid in weight gain. While RUTFs and F-100 milk were made to have the same nutritional value, RUTFs are beneficial as they are dehydrated and do not require much preparation. It is also important to note that infections are common in children with severe malnutrition and can further complicate treatment. Routine antibiotics, even in the absence of clinical infection, are generally given as a prophylactic measure, especially in regions with a high risk of infectious diseases. However, due to concerns about antibiotic resistance, there is debate over their routine use.
In addition, one case of mildly elevated liver enzymes (1 of 14; 7%), possibly related to bicalutamide, was observed but resolved spontaneously without discontinuation of therapy. Additional research is necessary to more clearly determine the true effectiveness and safety of bicalutamide and anastrozole in the treatment of FMPP. No long-term results for the BATT study have been published as of yet, but a 5-year follow-up of two of the boys in the study was published and reported continued effectiveness. It is intended that the study will continue until all of the boys reach adult final height, with an additional publication planned in the future. In addition to the BATT study, a variety of case reports and series of bicalutamide in combination with an aromatase inhibitor in male peripheral precocious puberty have been published. These case reports have described similar results as those of the BATT study. Alternatives to bicalutamide in the treatment of male peripheral precocious puberty include spironolactone, cyproterone acetate, and ketoconazole. Bicalutamide with anastrozole is considered to be superior to the combination of spironolactone and testolactone in peripheral precocious puberty, with greater efficacy and fewer side effects. This corresponds to the fact that bicalutamide is a much more potent and selective antiandrogen than spironolactone. Additionally, dosing is easier with bicalutamide, as it requires administration only once daily as opposed to twice daily at 12-hour intervals with spironolactone.
=== Puerto Rico === Chick-fil-A opened its first location in Puerto Rico in 2022 and by 2024 had expanded to seven restaurants, with the plan for up to 25 locations by 2030. The unique menu includes coffee 100% grown and roasted in Puerto Rico.
Sources: en.wikipedia.org
=== Radical anion preparation === In the original ETD experiments anthracene (C14H10) was used to generate reactive radical anions through negative chemical ionization. Several polycyclic aromatic hydrocarbon molecules have been used in subsequent experiments, with fluoranthene currently the preferred reagent. Fluoranthene has only about 40% efficiency in electron transfer, however, so other molecules with low electron affinity are being sought.
Epilogue: After Sally and Ollie's chapters have been completed, the player can choose one of two endings: either Arthur departs Wellington Wells for the mainland and continues his search for Percy, or takes a memory-destroying pill and rejoins the populace in their ignorance. If Arthur continues to the mainland, he encounters an impoverished young child complaining about the rainy weather, indicating other towns in England did not follow the path Wellington Wells did.
HMF can be found in low amounts in honey, fruit-juices and UHT-milk. Here, as well as in vinegars, jams, alcoholic products or biscuits, HMF can be used as an indicator for excess heat-treatment. For instance, fresh honey contains less than 15 mg/kg—depending on pH-value and temperature and age, and the codex alimentarius standard requires that honey have less than 40 mg/kg HMF to guarantee that the honey has not undergone heating during processing, except for tropical honeys which must be below 80 mg/kg. Higher quantities of HMF are found naturally in coffee and dried fruit. Several types of roasted coffee contained between 300 – 2900 mg/kg HMF. Dried plums were found to contain up to 2200 mg/kg HMF. In dark beer 13.3 mg/kg were found, bakery-products contained between 4.1 – 151 mg/kg HMF. It can be found in glucose syrup. HMF can form in high-fructose corn syrup (HFCS), levels around 20 mg/kg HMF were found, increasing during storage or heating. This is a problem for American beekeepers because they use HFCS as a source of sugar when there are not enough nectar sources to feed honeybees, and HMF is toxic to them. Adding bases such as soda ash or potash to neutralize the HFCS slows the formation of HMF. Depending on production-technology and storage, levels in food vary considerably. To evaluate the contribution of a food to HMF intake, its consumption-pattern has to be considered. Coffee is the food that has a very high relevance in terms of levels of HMF and quantities consumed. HMF is a natural component in heated food but usually present in low concentrations.
Sources: en.wikipedia.org
Native GLP-1 is a short-lived peptide cleared within one to two minutes by dipeptidyl peptidase-4 and related enzymes. Semaglutide keeps the receptor-binding backbone but adds substitutions and a lipid chain. These changes block the main cleavage site and allow reversible albumin binding, extending the half-life to roughly 165 hours.
Albumin is the most abundant protein in plasma and carries molecules that bear fatty-acid chains. Binding shields the peptide from renal filtration and from peptidases, keeping a circulating reservoir. Slow release from this reservoir produces sustained receptor occupancy and supports infrequent dosing.
The insulinotropic effect is glucose-dependent, meaning secretion increases mainly when glucose is elevated. This property is often described as lowering the chance of hypoglycaemia when the compound is used alone. Other glucose-lowering agents used at the same time can still cause low blood glucose.
Native GLP-1 is degraded within minutes by dipeptidyl peptidase-4 and neutral endopeptidases. Semaglutide carries a non-natural amino acid at position eight that blocks that cleavage, and a fatty diacid side chain that binds albumin. The result is a much longer duration of action than the native hormone.