GLP-1 and Satiety Glossary

It is an unwanted effect of a medicine, which can range from mild to serious. Labels speak of an adverse reaction when there is a possible link to the medicine; in trials, an adverse event is any health problem that appears during the study, whether or not the drug causes it. With GLP-1 receptor agonists the most common ones are digestive, such as nausea, diarrhea, vomiting or constipation.

Also called: adverse reaction, side effect, adverse event.

Sources: NCI dictionary; Wegovy US label (FDA); Wegovy European label (EMA).

More on: Nausea on GLP-1 · Symptom diary (in Spanish)

It is Spain’s national medicines agency, part of the Ministry of Health, and it ensures the quality, safety, efficacy and accurate information of medicines in Spain. It monitors their safety, publishes alerts on illegal or falsified products and runs the CIMA database. It works in coordination with the European Medicines Agency and plays a role similar to the FDA’s for medicines in the US.

Also called: Spanish Agency of Medicines and Medical Devices, Agencia Española de Medicamentos y Productos Sanitarios.

Sources: AEMPS, about the agency (in Spanish); AEMPS notice on illegal GLP-1 products (2025, in Spanish).

More on: Ozempic price in Spain (in Spanish) · Wegovy price in Spain (in Spanish)

It is the Spanish Ministry of Health search tool that shows whether each pack of a medicine is reimbursed by the National Health System, for which indications and under which conditions, such as a visado. In September 2026 it lists Ozempic as reimbursed with a visado for type 2 diabetes and Mounjaro as not reimbursed.

Also called: Spanish reimbursement status search.

Sources: BIFIMED, Spanish Ministry of Health (in Spanish); BIFIMED, Ozempic entry (in Spanish).

More on: Ozempic price in Spain (in Spanish) · Mounjaro price in Spain (in Spanish)

It is a biological medicine highly similar to another one already approved, called the reference medicine. In the European Union it is approved to the same standards of quality, safety and efficacy as any biological medicine. It is not an identical copy, because it is made from living organisms or complex processes, but it must have no clinically meaningful differences from the original.

Also called: biosimilar medicine.

Source: EMA, biosimilar medicines.

More on: What are GLP-1 medications? · GLP-1 drug pages (in Spanish)

It is weight in kilograms divided by height in meters squared. In adults, the WHO defines overweight as a BMI of 25 or more and obesity as 30 or more. It is a simple but imperfect measure: it does not tell fat from muscle or show where fat is stored.

Also called: BMI, body mass index, Quetelet index.

Sources: NCI dictionary; WHO, obesity and overweight.

More on: What BMI measures · BMI calculator (in Spanish)

It is the most prominent safety warning on an FDA label, printed inside a box at the top of the document. The US labels of Wegovy, Ozempic, Mounjaro and Zepbound carry one about thyroid C-cell tumors seen in rodents, and state that it is unknown whether they occur in humans. European labels do not use this format.

Also called: black box warning.

Sources: Wegovy US label (FDA); Ozempic US label (FDA); Mounjaro US label (FDA); Zepbound US label (FDA).

More on: Ozempic vs Mounjaro · What are GLP-1 medications?

It is a hormone the small intestine releases when fat and protein from food reach it. It contributes to satiation, that is, to ending the meal, and it also slows stomach emptying and stimulates the gallbladder and the pancreas. Its effect is short and acts mainly within the same meal.

Also called: CCK, cholecystokinin.

Sources: Steinert and colleagues (2017); Cummings and Overduin (2007).

More on: The science of satiety

It is the European Medicines Agency committee responsible for medicines for human use, and it meets once a month. It assesses marketing applications and issues a positive or negative opinion. Based on that opinion, the European Commission decides whether the medicine is authorized across the European Union.

Also called: Committee for Medicinal Products for Human Use.

Source: EMA, CHMP page.

More on: How much weight people lose on GLP-1 · GLP-1 drug pages (in Spanish)

It is the formation of stones in the gallbladder. It may cause no symptoms or cause nausea, vomiting and pain in the abdomen or back, and sometimes inflammation of the gallbladder (cholecystitis). In the adult weight-management trials of Wegovy injection, the US label reports gallstones in 1.6% of people on semaglutide versus 0.7% on placebo, and the European label gives 1.6% versus 1.1%.

Also called: gallstones.

Sources: MedlinePlus; Wegovy US label (FDA); Wegovy European label (EMA).

More on: What are GLP-1 medications? · Questions to ask your doctor (in Spanish)

It is the AEMPS public database with the official information on medicines authorized in Spain. For each one it shows the label, the package leaflet, the pack sizes, whether they are on the market and whether there are supply problems. It is the Spanish counterpart of DailyMed for looking up the Ozempic, Wegovy or Mounjaro label as approved in Spain.

Also called: Centro de Información online de Medicamentos, Spanish medicines database.

Source: CIMA, AEMPS medicines database (in Spanish).

More on: What are GLP-1 medications? · Wegovy price in Spain (in Spanish)

It is the body attached to the Spanish Ministry of Health that sets, with stated reasons, the reimbursement price of prescription medicines paid for by the National Health System. Its meetings also decide whether a medicine is included in public reimbursement. It does not set the price of medicines sold without reimbursement, which follow the notified price regime.

Also called: Interministerial Commission on Medicine Prices, Comisión Interministerial de Precios de los Medicamentos.

Sources: Spain’s medicines law (BOE, in Spanish); CIPM, Spanish Ministry of Health (in Spanish).

More on: Mounjaro price in Spain (in Spanish) · Ozempic price in Spain (in Spanish)

It is the body of Mexico’s Ministry of Health in charge of health regulation, control and oversight. Marketing authorizations for medicines in Mexico are granted through it. It also publishes alerts on counterfeit or unregistered products, such as the 2023 alert about fake Ozempic pens.

Also called: Federal Commission for the Protection against Sanitary Risks, Comisión Federal para la Protección contra Riesgos Sanitarios.

Sources: Mexico’s General Health Law (in Spanish); COFEPRIS risk alert on Ozempic (2023, in Spanish).

More on: Ozempic price in Mexico (in Spanish) · Mounjaro price in Mexico (in Spanish)

It is a study that follows groups of people who differ in something, such as taking a medicine or not, over time and compares what happens to them. There is no random draw, so the groups may differ in other factors, and the result shows an association, not proof that one thing causes the other. The large epidemiological studies that linked semaglutide to a higher risk of NAION are observational.

Also called: observational study.

Sources: NCI dictionary; EMA, PRAC conclusion on NAION (2025).

More on: What are GLP-1 medications? · Study summaries

It is a medicine a pharmacist prepares for a specific patient from a detailed prescription. In the US, compounded versions of semaglutide and tirzepatide are not FDA approved, and the FDA does not review their safety, effectiveness or quality before they are marketed. As of May 31, 2026, the FDA had received 990 adverse event reports with compounded semaglutide and more than 730 with compounded tirzepatide, including dosing errors, some of which required hospitalization.

Also called: compounding, compounded medication, fórmula magistral.

Sources: FDA, human drug compounding; FDA, unapproved GLP-1 drugs; Spain’s medicines law (BOE, in Spanish).

More on: What are GLP-1 medications? · Methodology (in Spanish)

It is the range of values that probably contains the true effect, calculated from the study data. The narrower it is, the more precise the result; if the interval for a difference does not include zero, that difference is usually considered statistically significant. In STEP 1, the difference in weight change versus placebo was −12.4 percentage points, with a 95% CI of −13.4 to −11.5.

Also called: 95% CI, confidence interval, CI.

Sources: STEP 1 trial (NEJM, 2021); NCI dictionary.

More on: How much weight people lose on GLP-1 · Trial comparison charts (in Spanish)

It is a situation in which a medicine should not be used because it could do more harm than good. Contraindications are listed in section 4 of an FDA label and in section 4.3 of a European SmPC. They are different from warnings and precautions (section 5 in the US, 4.4 in the European Union), which flag cases where the medicine can be used with extra care.

Sources: NCI dictionary; FDA labeling resources; European Commission, SmPC guideline.

More on: What are GLP-1 medications? · Questions to ask your doctor (in Spanish)

It is the share of the price of a reimbursed medicine that the patient pays at the pharmacy when picking it up with a National Health System prescription. The percentage depends on income and personal circumstances, and in some cases there are monthly caps. If a medicine is not reimbursed there is no copayment, because the full price is paid.

Also called: aportación, copay, pharmacy copayment.

Source: Spain’s medicines law (BOE, in Spanish).

More on: Ozempic price in Spain (in Spanish) · Monthly cost calculator (in Spanish)

It is a part of a trial in which only a subset of participants gets a DEXA scan, an x-ray test that tells fat, lean mass and bone apart. In STEP 1 it was done in 140 people and in SURMOUNT-1 in 160. Because the group is small, its results are less precise than those of the full trial.

Also called: DXA, DEXA scan, dual-energy x-ray absorptiometry.

Sources: NCI dictionary; STEP 1 DEXA substudy (2021); SURMOUNT-1 DEXA substudy (2025).

More on: Protein and muscle on GLP-1 · SURMOUNT-1 body composition

It is the gradual increase of the dose over the first weeks or months of treatment, in the steps set by the label. With GLP-1 receptor agonists its main purpose is to reduce the risk of digestive side effects, as the US and European Wegovy labels state. When to go up, stay or step down is a decision for your doctor.

Also called: titration, dose titration, escalation schedule.

Sources: Wegovy European label (EMA); Wegovy US label (FDA).

More on: Nausea on GLP-1 · Symptom diary (in Spanish)

It is a trial design in which neither the participants nor the researchers know who gets the medicine and who gets the placebo until the end. That way, expectations have less influence on how outcomes such as appetite or symptoms are measured and reported. STEP 1, the main obesity trial of semaglutide, was double-blind.

Also called: double-blind study, double masking.

Sources: NCI dictionary; STEP 1 trial (NEJM, 2021).

More on: How much weight people lose on GLP-1 · STEP 1 trial summary

It is the official document, approved by the regulator, that describes a medicine for health professionals: indications, dosing, contraindications, warnings, adverse reactions with their frequency and trial results. In the US it is the prescribing information approved by the FDA; in the European Union it is the summary of product characteristics (SmPC), whose sections are numbered the same way for every medicine, with 4.1 for indications, 4.2 for dosing and 4.8 for adverse reactions. It is the source of the drug data on this site.

Also called: official label, product information, ficha técnica.

Sources: FDA labeling resources; EMA glossary of regulatory terms; European Commission, SmPC guideline; CIMA, AEMPS medicines database (in Spanish).

More on: What are GLP-1 medications? · Methodology (in Spanish)

It is a medicine that activates two hormone receptors at once. Tirzepatide (Mounjaro, Zepbound) is a dual agonist of the GIP and GLP-1 receptors and is given once a week. Combining two pathways aims to add up effects on blood sugar and weight with a single molecule.

Also called: dual GIP and GLP-1 receptor agonist, co-agonist.

Sources: Mounjaro European label (EMA); Mounjaro US label (FDA); Zepbound US label (FDA).

More on: Ozempic vs Mounjaro · What are GLP-1 medications?

It is the calories a food provides per gram or per 100 g. Foods with a lot of water and fiber, such as vegetables, fruit or soups, have a low energy density: a lot of volume for few calories. In studies, lowering the energy density of meals leads people to eat fewer calories without feeling hungrier.

Also called: calorie density, caloric density.

Source: Rolls (2009).

More on: The most filling foods · Filling foods finder

It is the set of documents the European Medicines Agency (EMA) publishes on each medicine authorized through the centralized procedure. It includes how the medicine was assessed, a summary for the public and the product information, that is, the label and the package leaflet in every EU language. It is where to find the official European version of the Wegovy, Ozempic or Mounjaro label.

Also called: European public assessment report.

Source: EMA glossary of regulatory terms.

More on: What are GLP-1 medications? · Ozempic vs Mounjaro

It is the exact definition of the effect a trial sets out to measure, including what happens with people who stop treatment. The treatment-policy estimand counts everyone in their assigned group, whether they stopped or not; the trial product estimand estimates what would have happened if everyone had stayed on treatment. That is why one trial can report two figures: in STEP 1, 14.9% and 16.9% weight loss with semaglutide.

Also called: treatment-policy estimand, trial product estimand.

Sources: ICH E9 guideline and E9(R1) addendum; STEP 1 trial (NEJM, 2021); Wegovy European label (EMA).

More on: How much weight people lose on GLP-1 · STEP 1 trial summary

It is a medicine that is misrepresented as to its identity, its source or its distribution history, as defined in EU and Spanish law. The FDA has warned about counterfeit Ozempic in the US, and since 2023 the EMA, Spain’s AEMPS and Mexico’s COFEPRIS have warned about fake Ozempic pens and illegal products sold as GLP-1 drugs on websites and social media. They may contain no active ingredient, a different substance or the wrong dose.

Also called: counterfeit medicine, fake medicine, illegal medicine.

Sources: FDA, unapproved GLP-1 drugs; EMA, falsified medicines; EMA alert on fake Ozempic pens (2023); AEMPS notice on illegal GLP-1 products (2025, in Spanish); COFEPRIS risk alert on Ozempic (2023, in Spanish); Spain’s medicines law (BOE, in Spanish).

More on: What are GLP-1 medications? · Ozempic price in Mexico (in Spanish)

It is the page for each food on this site. It shows its values per 100 g and per typical serving from USDA FoodData Central, the estimated satiety score, the GLP-1 tags and, when available, the Holt satiety index. Each page cites the exact database entry its numbers come from.

Also called: food profile.

More on: Food database · Egg

It is one of the categories in which Mexico’s General Health Law classifies medicines for sale: those that require a prescription but can be refilled as many times as the prescriber indicates. It is different from fractions II and III, for which the pharmacy keeps the prescription or records it in control books. COFEPRIS has reminded the public that Ozempic is a fraction IV medicine.

Also called: fraction IV.

Sources: Mexico’s General Health Law (in Spanish); COFEPRIS risk alert on Ozempic (2023, in Spanish).

More on: Ozempic price in Mexico (in Spanish) · Mounjaro price in Mexico (in Spanish)

European labels place each adverse reaction in fixed bands: very common (1 in 10 people or more), common (1 in 100 to 1 in 10), uncommon (1 in 1,000 to 1 in 100), rare (1 in 10,000 to 1 in 1,000) and very rare (fewer than 1 in 10,000). A frequency listed as not known means it cannot be estimated from the available data, not that it is rare. US labels do not use these bands: they usually give the percentage of trial participants with each reaction, next to the placebo figure.

Also called: very common, common, uncommon, rare, very rare, not known.

Sources: Wegovy European label (EMA); European Commission, SmPC guideline; Wegovy US label (FDA).

More on: Nausea on GLP-1 · Symptom diary (in Spanish)

It is the passage of food from the stomach into the intestine. GLP-1 receptor agonists slow it down, which helps you feel full sooner and also contributes to nausea. For the same reason, their US and European labels warn of the risk of pulmonary aspiration during general anesthesia or deep sedation.

Also called: stomach emptying.

Sources: Wegovy US label (FDA); Wegovy European label (EMA); Cummings and Overduin (2007).

More on: Nausea on GLP-1 · The science of satiety

It is a disorder in which the stomach takes much longer than normal to empty, without any blockage. It causes nausea, vomiting, feeling full quickly and bloating, and diabetes is one of its known causes. The US and European Wegovy labels do not recommend Wegovy for people with severe gastroparesis.

Also called: delayed gastric emptying.

Sources: MedlinePlus; Wegovy US label (FDA); Wegovy European label (EMA).

More on: Nausea on GLP-1 · What are GLP-1 medications?

It is a medicine with the same active ingredient, in the same amount and dosage form as the original, that has been shown to be bioequivalent to it. It can be marketed once the patents and protection periods of the reference medicine expire, and it usually costs less. In December 2024 the FDA approved the first generic of liraglutide (Victoza), an older GLP-1 receptor agonist.

Also called: generic, generic medicine.

Sources: FDA, 2024 first generics; EMA, generic medicines; Spain’s medicines law (BOE, in Spanish).

More on: What are GLP-1 medications? · GLP-1 drug pages (in Spanish)

It is a hormone made mainly by the stomach that rises before meals and falls after eating. It is the only known gut hormone that stimulates appetite instead of curbing it. Its levels tend to rise with short sleep and after weight loss.

Also called: hunger hormone.

Sources: Cummings and colleagues (2001); Steinert and colleagues (2017); Taheri and colleagues (2004); Sumithran and colleagues (2011).

More on: The science of satiety · Sleep, stress, and appetite

It is a gut hormone that, like GLP-1, is released when you eat and boosts insulin secretion when blood sugar rises; that is why both are called incretins. Its receptor is found in the pancreas and also in fat tissue, according to the European Mounjaro label. Tirzepatide activates the GIP receptor as well as the GLP-1 receptor, and the European label describes its potency at the GIP receptor as similar to that of the natural hormone.

Also called: glucose-dependent insulinotropic polypeptide.

Sources: Mounjaro European label (EMA); Mounjaro US label (FDA); Steinert and colleagues (2017).

More on: Ozempic vs Mounjaro · What are GLP-1 medications?

It is a medicine that activates the same receptor as GLP-1 (glucagon-like peptide-1), a hormone the gut releases when you eat. According to the US and European labels, it increases insulin and lowers glucagon when blood sugar is high, slows stomach emptying and reduces appetite. Semaglutide, liraglutide and dulaglutide are GLP-1 receptor agonists; tirzepatide also acts on the GIP receptor.

Also called: GLP-1, GLP-1 analog, GLP-1 RA.

Sources: Wegovy European label (EMA); Mounjaro European label (EMA); Wegovy US label (FDA); Mounjaro US label (FDA).

More on: What are GLP-1 medications? · GLP-1 drug pages (in Spanish)

They are the practical tags attached to each food on this site, such as high in protein, easy to digest or may worsen nausea. Five are calculated from the food’s numbers (protein, fiber, energy density and water) and four are an editorial judgment based on the usual advice for patients. They are there to help you find your way, not rules: everyone tolerates foods differently.

Also called: On a GLP-1 tags.

More on: Filling foods finder · Food database

It is a way of comparing foods by the energy they provide instead of by their weight: how many grams of protein or fiber there are per 100 kcal. It shows which foods pack more of a nutrient per calorie; chicken breast, for example, provides far more protein per 100 kcal than nuts, even though nuts have more per 100 g. It is one of the criteria of this site’s satiety score.

Also called: nutrient density.

Source: Rolls (2009).

More on: Filling foods finder · Chicken breast

It is the time it takes for the amount of a medicine in the blood to fall by half. Semaglutide’s half-life is about one week, which is why it is taken once a week. According to the European Wegovy label, semaglutide stays in circulation for about 7 weeks after the last 2.4 mg dose.

Also called: elimination half-life, t½.

Sources: Wegovy European label (EMA); Wegovy US label (FDA).

More on: What are GLP-1 medications? · What happens when you stop

It is a blood test that reflects your average blood sugar over the past two to three months. It is used to diagnose and monitor diabetes: 6.5% or higher indicates diabetes, and 5.7% to 6.4% indicates prediabetes. In trials of GLP-1 receptor agonists in type 2 diabetes it is usually the main outcome.

Also called: A1C, hemoglobin A1c, glycated hemoglobin.

Source: MedlinePlus.

More on: What are GLP-1 medications? · Ozempic vs Mounjaro

It is keeping the body’s water in balance, with what you drink and the water in food. EFSA considers a total water intake of 2.0 liters a day adequate for adult women and 2.5 liters for men (about 68 and 85 fl oz), counting water from food. It matters on GLP-1 receptor agonists because vomiting or diarrhea can cause dehydration, and their labels warn of that risk.

Also called: fluid intake, water intake.

Sources: EFSA, dietary reference values; Wegovy US label (FDA); Wegovy European label (EMA).

More on: Hydration on GLP-1 · Water intake calculator (in Spanish)

It is a blood glucose level lower than is healthy; for many people with diabetes, below 70 mg/dL. It can cause shakiness, sweating, hunger, confusion or dizziness, and in severe cases loss of consciousness. With GLP-1 receptor agonists the risk rises mainly when they are combined with insulin or with insulin secretagogues such as sulfonylureas, according to their labels.

Also called: low blood sugar.

Sources: MedlinePlus; Wegovy US label (FDA); Wegovy European label (EMA).

More on: What are GLP-1 medications? · Questions to ask your doctor (in Spanish)

They are Mexico’s two large public social security institutions: the IMSS mainly covers formal private-sector workers and their families, and the ISSSTE covers government employees. Each has its own list of medicines, which follows the National Health Supplies Compendium. That is why what each institution offers may not match the compendium exactly.

Also called: Mexican Social Security Institute, Institute for Social Security and Services for State Workers, derechohabiencia.

Sources: Mexico’s Social Security Law (in Spanish); ISSSTE Law (in Spanish); IMSS institutional drug list (in Spanish); National Health Supplies Compendium 2025 (DOF, in Spanish).

More on: Ozempic price in Mexico (in Spanish) · Mounjaro price in Mexico (in Spanish)

It is the disease or condition a medicine is approved for, including its treatment, prevention or diagnosis. It appears in section 1 of an FDA label and in section 4.1 of a European SmPC. The same active ingredient can have different indications under different brands: Ozempic is approved for type 2 diabetes and Wegovy for weight management, although both are semaglutide.

Also called: approved indication, approved use.

Sources: EMA glossary of regulatory terms; Ozempic US label (FDA); Wegovy US label (FDA); Ozempic EPAR (EMA); Wegovy European label (EMA).

More on: Ozempic vs Mounjaro · What are GLP-1 medications?

It is a way of analyzing a trial that counts each participant in the group they were randomized to, even if they later stopped treatment or did not follow it well. This keeps the advantage of randomization and gives a result closer to what happens in practice. It usually yields somewhat more modest figures than analyzing only those who completed treatment.

Also called: ITT, intention to treat.

Source: ICH E9 guideline and E9(R1) addendum.

More on: How much weight people lose on GLP-1 · Trial comparison charts (in Spanish)

It is the unit used to measure the energy in food; in everyday language it is simply called a calorie. European labels give it alongside kilojoules (kJ). It is calculated at about 4 kcal per gram of protein or carbohydrate, 9 per gram of fat and 7 per gram of alcohol.

Also called: kcal, calorie, Calorie.

Sources: NCI dictionary; EU Regulation 1169/2011.

More on: Filling foods finder · Food database

It is everything the body weighs except fat: muscle, organs, water and other tissues. Losing weight means losing fat and also some lean mass; in the STEP 1 body composition substudy, about 38% of the weight lost with semaglutide was lean mass. Losing lean mass is not exactly the same as losing muscle.

Also called: fat-free mass, lean body mass.

Sources: STEP 1 DEXA substudy (2021); ACLM, ASN, OMA and The Obesity Society advisory (2025).

More on: Protein and muscle on GLP-1 · Protein calculator

It is a hormone made by fat cells that tells the brain how much energy is stored. Its levels rise with the amount of body fat and fall with weight loss, which contributes to increased hunger. In obesity it tends to be high, but the brain responds to it less well.

Sources: NCI dictionary; Klok and colleagues (2007); Sumithran and colleagues (2011).

More on: The science of satiety · Sleep, stress, and appetite

It is the dose treatment continues at once the initial escalation is over. The label states what it is and when it can be changed, and the specific choice is up to your doctor. It should not be confused with weight maintenance, the phase in which you try not to regain the weight you lost.

Sources: Wegovy European label (EMA); Wegovy US label (FDA).

More on: What are GLP-1 medications? · Questions to ask your doctor (in Spanish)

It is the inflammatory form of fatty liver disease linked to excess weight, diabetes or other metabolic factors: besides fat, there is damage to liver cells. Over the years it can lead to fibrosis and cirrhosis. In the US, the Wegovy label includes MASH with moderate to advanced liver fibrosis in adults, under accelerated approval.

Also called: metabolic dysfunction-associated steatohepatitis, NASH, nonalcoholic steatohepatitis.

Sources: MedlinePlus; NCI dictionary; Wegovy US label (FDA).

More on: Ozempic vs Mounjaro · What are GLP-1 medications?

It is an analysis that uses statistical methods to combine the results of several studies on the same question. It gives a more precise estimate than each study alone, but its quality depends on the quality of the studies it includes and on how similar they are. It is usually part of a systematic review, which searches for and selects all the studies in an orderly way.

Sources: NCI dictionary; West and colleagues (BMJ, 2026).

More on: What happens when you stop · Study summaries

It is the drop in resting energy expenditure that happens with weight loss and goes beyond what a smaller body explains. In a study of 14 people who had lost 58 kg (128 lb) on average, six years later they burned about 500 kcal a day less at rest than expected for their new body size. It is one of the reasons weight tends to level off and to come back.

Also called: adaptive thermogenesis.

Source: Fothergill and colleagues (2016).

More on: Weight-loss plateau on GLP-1 · What happens when you stop

It is damage to the optic nerve from a lack of blood flow that causes sudden vision loss. In June 2025, the EMA’s PRAC concluded that it is a very rare adverse effect of semaglutide, affecting up to 1 in 10,000 people treated. The European label says to stop semaglutide if the diagnosis is confirmed.

Also called: non-arteritic anterior ischemic optic neuropathy, NOIANA.

Sources: EMA, PRAC conclusion on NAION (2025); Wegovy European label (EMA).

More on: What are GLP-1 medications? · Questions to ask your doctor (in Spanish)

It is the official list of medicines and supplies that the public institutions of Mexico’s National Health System must follow. It is drawn up by the General Health Council and published, with its updates, in the Diario Oficial de la Federación. In June 2026 an amendment to the semaglutide entry was published.

Also called: Compendio Nacional de Insumos para la Salud, CNIS, Cuadro Básico (former name).

Sources: Mexico’s General Health Law (in Spanish); National Health Supplies Compendium 2025 (DOF, in Spanish); Compendium update for semaglutide (DOF, 2026, in Spanish).

More on: Ozempic price in Mexico (in Spanish) · Mounjaro price in Mexico (in Spanish)

It is the Spanish Ministry of Health database of medicines included in the National Health System pharmacy benefit, published every month. For each pack, identified by its national code, it lists the retail price with VAT and the copayment type, among other data. It is the source of official prices for reimbursed medicines in Spain.

Also called: Nomenclátor de facturación.

Source: Nomenclátor, Spanish Ministry of Health (in Spanish).

More on: Ozempic price in Spain (in Spanish) · Monthly cost calculator (in Spanish)

It is the pricing regime for medicines sold in Spain outside National Health System reimbursement. The manufacturer notifies the price to the Ministry of Health, which can object to it on public interest grounds. That is the case for Mounjaro and Wegovy, which are not reimbursed: their price is not set by the CIPM.

Also called: precio notificado, free pricing, non-reimbursed price.

Sources: Spain’s medicines law (BOE, in Spanish); BIFIMED, Spanish Ministry of Health (in Spanish).

More on: Mounjaro price in Spain (in Spanish) · Wegovy price in Spain (in Spanish)

It is a disorder in which breathing stops repeatedly during sleep, in pauses of 10 seconds or more, because the upper airway closes. It causes loud snoring and daytime sleepiness, and it is more common with obesity. In the US, the Zepbound (tirzepatide) label includes moderate to severe obstructive sleep apnea in adults with obesity.

Also called: sleep apnea, OSA.

Sources: NCI dictionary; MedlinePlus; Zepbound US label (FDA).

More on: Sleep, stress, and appetite · SURMOUNT-OSA trial summary

It is using an approved medicine for a disease, a group of patients or a dose that is not on its label. The FDA says doctors may generally prescribe a drug off label when they judge it medically appropriate for their patient, while Spanish law treats it as exceptional. Using Ozempic, which is approved for type 2 diabetes, only to lose weight is an example of off-label use.

Also called: unapproved use of an approved drug.

Sources: NCI dictionary; FDA, off-label use; Spain’s medicines law (BOE, in Spanish).

More on: What are GLP-1 medications? · Ozempic price in Spain (in Spanish)

It is a trial in which participants and researchers know which treatment each person gets. It is simpler when the treatments are given differently, but expectations can influence outcomes such as appetite or reported side effects. SURMOUNT-5, which compared tirzepatide with semaglutide, was an open-label trial.

Also called: open-label study, nonblinded study, unblinded.

Sources: NCI dictionary; SURMOUNT-5 trial (NEJM, 2025).

More on: Ozempic vs Mounjaro · SURMOUNT-5 trial summary

It is the patient leaflet that comes inside the box of every medicine in the European Union. It sums up the label in plain language: what the medicine is for, how to use it, precautions and possible side effects. Its text is approved by the regulator, and in the US the closest documents are the FDA-approved patient labeling, such as the Medication Guide.

Also called: patient information leaflet, PIL, prospecto.

Sources: EMA glossary of regulatory terms; CIMA, AEMPS medicines database (in Spanish); FDA labeling resources.

More on: Nausea on GLP-1 · Symptom diary (in Spanish)

It is inflammation of the pancreas. The acute form causes severe pain in the upper abdomen, often with nausea and vomiting. The US and European Wegovy and Mounjaro labels say to stop treatment if it is suspected, and the European labels list it as uncommon.

Also called: acute pancreatitis.

Sources: MedlinePlus; Wegovy US label (FDA); Mounjaro US label (FDA); Wegovy European label (EMA); Mounjaro European label (EMA).

More on: Nausea on GLP-1 · Questions to ask your doctor (in Spanish)

It is the ongoing monitoring of medicine safety: detecting, assessing, understanding and preventing adverse effects. It draws on reports from health professionals and patients, on studies and on the medical literature. It can lead to label changes, as when NAION was added to the European semaglutide labels as a very rare adverse effect.

Also called: drug safety monitoring.

Sources: EMA, pharmacovigilance; AEMPS, pharmacovigilance (in Spanish); NCI dictionary.

More on: What are GLP-1 medications? · Symptom diary (in Spanish)

It is a substance with no drug effect that looks the same and is given the same way as the medicine being tested, such as an identical injection with no active ingredient. Comparing against placebo separates the drug’s effect from the effect of being in a study, of diet advice and of the passage of time. In STEP 1, the placebo group also lost 2.4% of body weight on average.

Sources: NCI dictionary; STEP 1 trial (NEJM, 2021).

More on: How much weight people lose on GLP-1 · STEP 1 trial summary

It is the result of the treated group minus that of the placebo group, and it is the best estimate of what is due to the medicine. In STEP 1, weight fell by 14.9% with semaglutide and by 2.4% with placebo, so the difference was 12.4 percentage points. The rest of the loss is explained by the diet and activity advice both groups received and by other factors.

Also called: treatment difference, difference versus placebo.

Source: STEP 1 trial (NEJM, 2021).

More on: How much weight people lose on GLP-1 · Trial comparison charts (in Spanish)

It is an analysis decided after a trial’s data have been collected, instead of being planned in its protocol from the start. It is useful for generating hypotheses, but it is more likely to find differences by chance, especially when many subgroups are examined. Many post hoc analyses of GLP-1 trials, such as those on early response in SURMOUNT-1, are funded by the manufacturers.

Also called: after-the-fact analysis.

Sources: ICH E9 guideline and E9(R1) addendum; Ard and colleagues (2025).

More on: How much weight people lose on GLP-1 · SURMOUNT-4 post hoc analysis

It is the European Medicines Agency committee responsible for assessing and monitoring the safety of medicines for human use. It meets once a month and publishes its agendas, minutes and conclusions. In June 2025 it concluded that NAION is a very rare adverse effect of semaglutide and recommended adding it to the European labels.

Also called: Pharmacovigilance Risk Assessment Committee.

Sources: EMA, PRAC page; EMA, PRAC conclusion on NAION (2025).

More on: What are GLP-1 medications? · Questions to ask your doctor (in Spanish)

It is a condition in which blood sugar is higher than normal, but not high enough to diagnose type 2 diabetes. It usually causes no symptoms and raises the risk of diabetes, heart disease and stroke. An HbA1c of 5.7% to 6.4% is one of the criteria that define it.

Sources: NCI dictionary; MedlinePlus.

More on: How much weight people lose on GLP-1 · What are GLP-1 medications?

It is the label the FDA approves for each prescription drug in the US, the counterpart of the European SmPC. It can be looked up in the DailyMed and Drugs@FDA databases. It may differ from the European label in approved indications, dosing or warnings, so it is worth checking which country a figure comes from.

Also called: FDA label, US label, package insert, PI.

Sources: FDA labeling resources; Wegovy US label (FDA).

More on: Ozempic vs Mounjaro · What are GLP-1 medications?

It is a medicine that can only be dispensed with a prescription from an authorized professional, because it can be dangerous without medical supervision or because it is injected, among other reasons. In Spain the AEMPS decides this when it authorizes a medicine, and GLP-1 medicines cannot be sold online there. In Mexico the matching category is fraction IV of the General Health Law.

Also called: prescription-only medicine, Rx, medicamento con receta.

Sources: Spain’s medicines law (BOE, in Spanish); AEMPS notice on illegal GLP-1 products (2025, in Spanish); Mexico’s General Health Law (in Spanish).

More on: What are GLP-1 medications? · Questions to ask your doctor (in Spanish)

It is the usual way to express daily protein intake relative to body weight. The European Food Safety Authority (EFSA) sets a reference intake of 0.83 g per kilogram per day for healthy adults, about 0.38 g per pound. Several expert groups propose higher figures for older adults and during substantial weight loss.

Also called: g/kg/day, grams of protein per kilogram.

Sources: EFSA, dietary reference values; PROT-AGE Study Group (2013); ACLM, ASN, OMA and The Obesity Society advisory (2025).

More on: Protein calculator · Protein and muscle on GLP-1

It is the passage of stomach or mouth contents into the lungs, which can cause pneumonia. The labels of GLP-1 receptor agonists report cases during general anesthesia or deep sedation, because the stomach may not be empty. The US labels tell prescribers to ask patients to mention any planned surgery or procedure.

Also called: aspiration.

Sources: Wegovy US label (FDA); Mounjaro US label (FDA); Wegovy European label (EMA); MedlinePlus.

More on: What are GLP-1 medications? · Questions to ask your doctor (in Spanish)

It is the final pharmacy price of a medicine in Spain; the Nomenclátor publishes it with value-added tax (VAT) included. If the medicine is reimbursed and dispensed with a National Health System prescription, the patient does not pay the PVP but a copayment calculated as a percentage of it. If it is not reimbursed, the full price is paid.

Also called: precio de venta al público, retail price, retail price including VAT.

Sources: Nomenclátor, Spanish Ministry of Health (in Spanish); Spain’s medicines law (BOE, in Spanish).

More on: Ozempic price in Spain (in Spanish) · Monthly cost calculator (in Spanish)

It is a hormone released by cells at the end of the gut after eating, in proportion to the calories eaten. It reduces appetite: in a 2003 study, an infusion of PYY3-36 made people with and without obesity eat about 30% less at the next meal. Together with GLP-1 and CCK, it is one of the gut signals of satiety.

Also called: PYY, peptide YY, PYY3-36.

Sources: Batterham and colleagues (2003); Steinert and colleagues (2017).

More on: The science of satiety

It is a study in which a random draw decides which participants get the treatment being tested and which get the comparator, such as a placebo or another medicine. The draw makes the groups similar at the start, so differences at the end can be attributed to the treatment with more confidence. The large obesity trials of semaglutide and tirzepatide, such as STEP 1 or SURMOUNT-1, are of this kind.

Also called: RCT, randomized clinical trial.

Sources: NCI dictionary; STEP 1 trial (NEJM, 2021).

More on: How much weight people lose on GLP-1 · STEP 1 trial summary

It is a lower copayment for medicines in certain therapeutic groups, generally for chronic diseases. By law, it is 10% of the retail price with a maximum of €4.98. According to the Nomenclátor, Ozempic has a reduced copayment when it is dispensed as reimbursed for type 2 diabetes.

Also called: aportación reducida.

Sources: Spain’s medicines law (BOE, in Spanish); Nomenclátor, Spanish Ministry of Health (in Spanish).

More on: Ozempic price in Spain (in Spanish) · Monthly cost calculator (in Spanish)

It is the authorization Mexico’s General Health Law requires to market a medicine. It is granted by the Ministry of Health through COFEPRIS for an initial 5 years and can be renewed. A product without it cannot be sold legally in Mexico; the counterpart is a marketing authorization in the European Union and FDA approval in the US.

Also called: sanitary registration, marketing authorization.

Source: Mexico’s General Health Law (in Spanish).

More on: Ozempic price in Mexico (in Spanish) · Mounjaro price in Mexico (in Spanish)

It is the loss of muscle mass, strength and function, more common in older adults. It raises the risk of falls, fractures and loss of independence. When a lot of weight is lost, especially past a certain age, guidelines stress eating enough protein and doing strength training to preserve muscle.

Sources: NCI dictionary; ACLM, ASN, OMA and The Obesity Society advisory (2025).

More on: Protein and muscle on GLP-1 · Protein calculator

It is the process that brings a meal to an end: the feeling of fullness that builds while you eat. It determines the size of each meal. It is distinct from satiety, which lasts from the end of one meal until the next.

Also called: intra-meal satiety, fullness during a meal.

Source: Blundell and colleagues (2010).

More on: The science of satiety

It is the absence of hunger that lasts after a meal and delays the next one. It depends on gut hormones such as GLP-1, PYY and CCK, on how full the stomach is and on the food itself: protein, fiber and water are more filling per calorie. GLP-1 receptor agonists increase satiety, which is why people eat less on them.

Sources: Blundell and colleagues (2010); Steinert and colleagues (2017).

More on: The science of satiety · The most filling foods

It is a measure of how filling a food is compared with white bread, which is given a score of 100, published by Holt and colleagues in 1995. Volunteers ate 240 kcal servings of 38 foods and rated their fullness over the next two hours. Boiled potatoes scored highest (323) and croissants lowest (47).

Also called: Holt satiety index.

Source: Holt and colleagues (1995).

More on: The most filling foods · Boiled potato

It is this site’s own estimate, from 1 to 5, of how filling a food is per calorie. It is calculated with a public rule from the values per 100 g: it adds points for low energy density, for protein and fiber per 100 kcal and for water, and subtracts them for high energy density or for being a drink. It is an approximation, not a measurement; when a Holt satiety index exists, that figure is better.

Also called: estimated satiety.

More on: Food database · Filling foods finder

It is the amount of a food usually eaten at one time, such as one egg or a bowl of lentils. On the food pages of this site, the typical serving is a realistic amount used for the calculations, not a recommendation of how much to eat. Comparing foods per serving and per 100 g gives different answers, and both are useful.

Also called: portion, serving size.

More on: Filling foods finder · Food database

It stands for summary of product characteristics, the official name of the drug label in the European Union. It is the same document that Spain’s CIMA database shows as the ficha técnica, with the same sections. Its US counterpart is the prescribing information approved by the FDA.

Also called: summary of product characteristics, European label.

Sources: EMA glossary of regulatory terms; FDA labeling resources.

More on: What are GLP-1 medications? · Methodology (in Spanish)

It is the inclusion of a medicine in the pharmacy benefit of Spain’s National Health System (SNS), decided by the Ministry of Health for specific indications and conditions. If it is reimbursed, the patient pays only a copayment; if not, they pay the full price even with a prescription. In other countries coverage depends on other bodies, such as social health insurance funds (obras sociales) in Argentina or social security institutions in Mexico.

Also called: financiación del SNS, public coverage, reimbursed medicine.

Sources: Spain’s medicines law (BOE, in Spanish); BIFIMED, Spanish Ministry of Health (in Spanish).

More on: Ozempic price in Spain (in Spanish) · Wegovy price in Spain (in Spanish)

Fiber is the part of plant foods the body does not digest. Soluble fiber, plentiful in oats, beans and apples, forms a gel that slows digestion and may help lower cholesterol and blood sugar; insoluble fiber, found in bran, whole grains and seeds, adds bulk to stool and helps it move along. The European Food Safety Authority considers 25 g of fiber a day adequate for normal bowel function in adults.

Also called: dietary fiber.

Sources: NCI dictionary; MedlinePlus; EFSA, dietary reference values; Clark and Slavin (2013).

More on: Constipation on GLP-1 · Fiber calculator (in Spanish)

It is a medicine that activates three hormone receptors at once. Retatrutide, which Eli Lilly is developing, acts on the GIP, GLP-1 and glucagon receptors. In its phase 2 trial, published in 2023, the highest dose reduced weight by 24.2% on average over 48 weeks. It is not approved in any country.

Also called: triple hormone receptor agonist.

Source: Retatrutide phase 2 trial (NEJM, 2023).

More on: How much weight people lose on GLP-1 · Retatrutide phase 2 trial

It is a chronic disease in which blood sugar is high because the body does not respond well to insulin and, over time, does not make enough of it. It is the most common form of diabetes. It was the first indication of GLP-1 receptor agonists: Ozempic, for example, was first approved for it in the US in 2017 and in the European Union in 2018.

Also called: T2D, type 2 diabetes mellitus.

Sources: MedlinePlus; Ozempic US label (FDA); Ozempic EPAR (EMA).

More on: What are GLP-1 medications? · Ozempic vs Mounjaro

It is an industrial product made mostly from substances extracted or modified from foods, such as sugars, oils, starches or isolated proteins, plus additives, according to the NOVA classification. Examples include packaged pastries, soda, sugary cereals and fried snacks. In a trial with 20 adults staying in a clinical center, an ultra-processed diet led them to eat about 500 kcal more a day than an unprocessed one.

Also called: UPF, ultra-processed.

Sources: FAO, NOVA classification (2019); Hall and colleagues (2019).

More on: The most filling foods · Ultra-processed foods and sweets

It is an authorization required before some reimbursed medicines can be dispensed in Spain: the regional health service checks that the prescription meets the reimbursement conditions, much like a prior authorization from a US insurer. Ozempic, for example, is only reimbursed with a visado for type 2 diabetes in people with a BMI of 30 or more, combined with other diabetes drugs. The process and its timelines vary by region.

Also called: visado de inspección, prescription authorization, prior authorization.

Sources: BIFIMED, Ozempic entry (in Spanish); IB-Salut, prescription authorization (in Spanish).

More on: Ozempic price in Spain (in Spanish)

It is the weight people usually put back on after stopping an obesity treatment. In the STEP 1 extension, people who had lost 17.3% on average with semaglutide regained about two thirds of it in the year after stopping. It is mainly explained by the return of appetite and by the body’s adaptation to weight loss.

Also called: rebound, rebound weight gain.

Sources: STEP 1 extension (2022); Sumithran and colleagues (2011).

More on: What happens when you stop · STEP 1 extension summary

It is the point at which weight stops going down during treatment, even though nothing else has changed. It happens because the body burns less and appetite pushes back until a new balance is reached, lower than the starting one. In an analysis of SURMOUNT-1, almost 9 in 10 participants on tirzepatide who had lost at least 5% were on a plateau by week 72.

Also called: plateau, stall.

Sources: Horn and colleagues (2025); Fothergill and colleagues (2016).

More on: Weight-loss plateau on GLP-1 · How much weight people lose on GLP-1