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GLP-1 glossary: terms in the label

GLP-1 labels use a vocabulary that is clear to clinicians and confusing to almost everyone else, and it keeps growing: 2025 and 2026 brought new products, new indications and new warning headings. This glossary explains the terms you are most likely to meet, grouped by theme. Each definition is tied to a current US label, with the section number so you can find it, or to the FDA, MedlinePlus, the NIDDK or a peer-reviewed review.

Published · Updated · GLP-1 medications · Written by the PepLabo editorial team

The medicines and how they are named

  • GLP-1 (glucagon-like peptide-1): a hormone from the gut. The Wegovy® and Foundayo™ labels call it a physiological regulator of appetite and calorie intake (section 12.1) [1][5].
  • Incretin: a gut hormone that strengthens the insulin response to a meal. A peer-reviewed review names GIP and GLP-1 as the main incretins [9].
  • GIP (glucose-dependent insulinotropic polypeptide): a second gut hormone. Tirzepatide acts on both GIP and GLP-1 receptors; the Zepbound® label says nonclinical studies suggest GIP may add to the regulation of food intake (12.1) [2].
  • Receptor agonist: a medicine that binds to and activates a receptor. The labels say semaglutide and orforglipron activate the GLP-1 receptor, and tirzepatide activates both the GIP and GLP-1 receptors (12.1) [1][2][5].
  • Established pharmacologic class: the group name printed with the indication, such as “GLP-1 receptor agonist” on the Wegovy® and Foundayo™ labels, or “GIP receptor and GLP-1 receptor agonist” on Zepbound® [7][1][2][5].
  • Analogue: a modified version of a natural molecule. The Wegovy® label describes semaglutide as a GLP-1 analogue with 94% sequence homology to human GLP-1 (12.1) [1].
  • DPP-4: an enzyme that breaks down natural GLP-1. The Saxenda® label says this gives natural GLP-1 a half-life of only 1.5 to 2 minutes, whereas liraglutide is stable against it (12.1) [6].
  • Foundayo™ (orforglipron): a once-daily GLP-1 receptor agonist tablet for weight, first approved in the US in 2026 (Highlights, 1, 11) [5].
  • Wegovy® tablets: semaglutide tablets that share the Wegovy® label with the injection, approved for weight reduction and for lowering cardiovascular risk in adults (1, 11) [1].
  • Ozempic® tablets: semaglutide tablets for type 2 diabetes that share a label with Rybelsus®. The FDA approved the name in January 2026 for the newer Rybelsus® formulation, and the label explains how the two tablet products correspond (2.3) [4][8].

Words about doses and forms

  • Dose escalation or titration: starting low and raising the dose in steps. The Zepbound® label says the steps are there to reduce the risk of stomach and bowel side effects (2.1) [2].
  • Maintenance dosage: the dose a person stays on once the steps are complete. In the Zepbound® label, the starting dose is for beginning treatment and is not approved as a maintenance dosage (2.1) [2].
  • MTD (maximum tolerated dose): the term the Zepbound® trials use for the highest dose each person tolerated, which was 10 mg or 15 mg (14.1) [2].
  • Subcutaneous: injected under the skin, the phrase the Wegovy® Medication Guide uses [1].
  • SNAC (salcaprozate sodium): an absorption enhancer in Wegovy®, Rybelsus® and Ozempic® tablets. Because SNAC passes into breast milk, the Wegovy® label advises that breastfeeding is not recommended while taking the tablets, noting that injectable semaglutide contains no SNAC (8.2, 11, 12.3) [1][4].
  • Bioavailability: the share of a dose that reaches the bloodstream. The Wegovy® label estimates about 1% to 2% for semaglutide tablets and 89% for the injection; the Foundayo™ label gives 77% for orforglipron after a 0.8 mg dose (12.3) [1][5].
  • Never share a pen: a 2026 warning heading in the Wegovy® label. A pen must not be shared between patients even if the needle is changed, because of the risk of passing on blood-borne infections (5.11) [1].

What happens in the body

  • Half-life: the time it takes for the amount of medicine in the blood to fall by half. The Ozempic® label gives about one week for semaglutide, the Zepbound® label about 5 to 6 days for tirzepatide and the Foundayo™ label about 29 to 49 hours for orforglipron (12.3) [3][2][5].
  • Steady state: the point at which levels stop building up with repeated doses. The Ozempic® label puts it at 4 to 5 weeks of weekly dosing, the Zepbound® label at 4 weeks and the Foundayo™ label at about 1 week of daily dosing (12.3) [3][2][5].
  • Albumin binding: attachment to albumin, the main protein in blood, which slows removal. The Zepbound® label credits a C20 fatty diacid on tirzepatide for this. Semaglutide is more than 99% and tirzepatide about 99% bound to albumin, and orforglipron is more than 99% bound to plasma proteins (12.1, 12.3) [3][2][5].
  • Gastric emptying: how fast food leaves the stomach. The labels say these medicines delay it, and the Zepbound® and Foundayo™ labels add that the delay is largest after the first dose and lessens over time (12.2) [1][2][5].
  • CYP3A4: a liver enzyme that breaks down many medicines, including orforglipron. Strong blockers of this enzyme raise orforglipron levels and strong inducers lower them, so the Foundayo™ label has specific instructions for use alongside such medicines (2.2, 7.1, 12.3) [5].

Warning words

  • Boxed warning: the FDA’s warning in a bold black-bordered box at the top of the full prescribing information, holding contraindications or warnings about serious adverse reactions that may lead to death or serious injury [7].
  • Contraindication: a situation in which the risk clearly outweighs any possible benefit and the medicine must not be used [7].
  • Thyroid C-cell tumours: tumours of one cell type in the thyroid. Semaglutide caused them in mice and rats, and it is unknown whether this happens in people (5.1) [1]. Orforglipron is the exception: it is not active in rats or mice and did not cause such tumours there, and the Foundayo™ label says the human relevance of the rodent findings with other GLP-1 products has not been determined (Boxed Warning) [5].
  • MTC (medullary thyroid carcinoma): a thyroid cancer of the C-cells. Having had it, or having it in your family, is a reason the labels give not to use these medicines (4, 5.1) [1][5].
  • MEN 2 (Multiple Endocrine Neoplasia syndrome type 2): an endocrine system condition, and also a reason the labels give not to use them [1][5].
  • Calcitonin: a blood marker. The Wegovy® label says routine calcitonin testing or thyroid ultrasound is of uncertain value for spotting MTC early, and that a clearly raised value needs further evaluation (5.1) [1].
  • Hypersensitivity: an allergic reaction. Anaphylaxis and angioedema, a type of swelling, are the serious forms the labels name (5.7) [1].
  • Severe gastrointestinal adverse reactions: a warning heading in the current labels. In the Wegovy® weight trials such reactions were reported in 4.1% of people on the injection against 0.9% on placebo, and 2% on the tablets against 0%; the label does not recommend Wegovy® in severe gastroparesis (5.6) [1].
  • Acute kidney injury due to volume depletion: sudden kidney damage, most often reported after nausea, vomiting or diarrhea led to dehydration (5.5) [1].
  • Pulmonary aspiration: stomach contents entering the lungs during general anesthesia or deep sedation. Because these medicines slow stomach emptying, the labels ask you to tell your care team about them before any planned procedure (5.10) [1].

Blood sugar words

  • Hypoglycemia: low blood sugar. The Ozempic® Medication Guide lists signs such as dizziness, blurred vision, sweating, shakiness, confusion, headache, a fast heartbeat and hunger [3].
  • Insulin secretagogue: the labels’ term for medicines such as sulfonylureas that increase insulin release. Combining one with a GLP-1 medicine, or using insulin, can raise the risk of hypoglycemia (5.5) [3].
  • Glucose-dependent: the Ozempic® label uses it to mean that insulin release rises and glucagon falls when blood sugar is high (12.1) [3].
  • HbA1c: a blood test that, according to MedlinePlus, shows your average blood sugar over the past two to three months [13].

Kidney, heart, liver and sleep measures

  • eGFR (estimated glomerular filtration rate): an estimate of how well the kidneys filter blood, usually calculated from creatinine, as MedlinePlus explains [12].
  • UACR (urine albumin-to-creatinine ratio): a urine test for the protein albumin; MedlinePlus says abnormal amounts may be an early sign of kidney disease [14].
  • CKD and end-stage kidney disease: chronic kidney disease, and its most advanced stage. The Ozempic® label includes an indication to lower the risk of lasting eGFR decline, end-stage kidney disease and cardiovascular death in adults with type 2 diabetes and CKD (1) [3].
  • MACE (major adverse cardiovascular events): cardiovascular death, non-fatal heart attack or non-fatal stroke counted together, as in the Wegovy® indication (1) [1].
  • MASH (metabolic dysfunction-associated steatohepatitis): the current name for what used to be called NASH, a serious liver disease in which fat buildup causes inflammation and scarring [18]. Wegovy® injection is indicated for noncirrhotic MASH with moderate to advanced fibrosis, stages F2 to F3 (1, 14.4) [1].
  • Accelerated approval: an FDA pathway that allows earlier approval for a serious condition based on a surrogate endpoint, a marker thought to predict benefit, with confirmatory trials still required [10]. The Wegovy® MASH indication is approved this way, and continued approval may depend on a confirmatory trial (1) [1].
  • BMI (body mass index): weight in relation to height. The NIDDK says a BMI between 25 and 30 is overweight and 30 or more is obesity [16].
  • OSA and AHI: obstructive sleep apnea, in which the airway collapses or is blocked during sleep [15], and the apnea-hypopnea index, breathing events per hour of sleep. The Zepbound® studies defined moderate OSA as an AHI of 15 to 30 and severe as 30 or more (1, 14.2) [2].

Words about the label itself

  • Initial U.S. Approval: the year the FDA first approved the molecule, not the brand; it is why the Zepbound® label says 2022 [7][2].
  • Recent Major Changes: a box in the Highlights listing substantive changes to key sections, with the month and year of each [7].
  • Revision date: the month and year of the latest change to the prescribing information, large or small [7].
  • Limitations of use: a statement of what a medicine is not for or should not be combined with. The Foundayo™ label, for example, does not recommend using it with another GLP-1 receptor agonist (1) [5].
  • “Reduce excess body weight and maintain weight reduction long term”: the indication wording in the current Wegovy®, Zepbound® and Foundayo™ labels (1) [1][2][5]. When Zepbound® was approved in 2023, the FDA described it as a medicine for “chronic weight management” [17].
  • Adverse reaction: the FDA defines it as an undesirable effect reasonably associated with a medicine, with some basis to believe the medicine caused it [7].
  • Eructation: belching, the word the Wegovy® label uses for it (6.1) [1].
  • Dysesthesia: altered skin sensations such as burning, pain or sensitivity of the skin; the Wegovy® label says it became more frequent as the dose and blood levels rose (6.1) [1].
  • Generic and compounded: a generic is FDA approved and shown to be therapeutically equivalent to the brand, while a compounded drug is not FDA approved [11].

Putting the words to use

Knowing the vocabulary makes the labels, and your appointments, easier to follow. Labels change, so check the revision date of the one you are reading; if a term in your own label is not here, your pharmacist can explain it.

Wegovy®, Ozempic®, Rybelsus® and Saxenda® are registered trademarks of Novo Nordisk A/S. Zepbound® is a registered trademark of Eli Lilly and Company, and Foundayo™ is a trademark of Eli Lilly and Company. PepLabo is not affiliated with or endorsed by Novo Nordisk or Eli Lilly and Company.

Questions

What does GLP-1 mean?

GLP-1 stands for glucagon-like peptide-1, a hormone released by the gut. The labels describe it as a physiological regulator of appetite and calorie intake [1][5]. GLP-1 medicines activate the same receptor this hormone uses.

What is the difference between titration and maintenance?

Titration, or dose escalation, is the stepped increase at the start of treatment, meant to reduce stomach and bowel side effects. The maintenance dosage is the dose reached at the end of those steps [2]. Your prescriber sets both.

What do MTC and MEN 2 mean on a GLP-1 label?

MTC is medullary thyroid carcinoma, a thyroid cancer of the C-cells. MEN 2 is Multiple Endocrine Neoplasia syndrome type 2, an endocrine condition. Either one in you, or MTC in your family, is a reason the labels give not to use these medicines, including the Foundayo™ label [1][5].

What is SNAC in semaglutide tablets?

SNAC, salcaprozate sodium, is an absorption enhancer in Wegovy®, Rybelsus® and Ozempic® tablets that helps semaglutide be absorbed, mainly in the stomach [1][4]. The Wegovy® label advises against breastfeeding while taking its tablets because SNAC reaches breast milk [1].

What does accelerated approval mean on the Wegovy® label?

It means the MASH indication was approved on the basis of a surrogate measure, here liver biopsy findings, before long-term outcomes are known [1][10]. The label says continued approval may depend on a confirmatory trial [1].

Is Foundayo™ a different kind of GLP-1 medicine?

Its label calls orforglipron a GLP-1 receptor agonist, like the others, but it is a once-daily tablet with a half-life of about 29 to 49 hours that is broken down by the liver enzyme CYP3A4 [5]. Its boxed warning also differs, because orforglipron is not active in rats or mice [5].

Sources

Sources checked on

  1. WEGOVY® (semaglutide) injection and tablets Prescribing Information and Medication Guide, Novo Nordisk Revised 06/2026. Recent Major Changes; sections 1, 5.1, 5.5–5.7, 5.10, 5.11, 6.1, 8.2, 11, 12.1–12.3, 14.4 and Medication Guide.
  2. ZEPBOUND® (tirzepatide) Prescribing Information, Eli Lilly and Company Revised 08/2026. Highlights; sections 1, 2.1, 12.1–12.3, 14.1 and 14.2.
  3. OZEMPIC® (semaglutide) Prescribing Information and Medication Guide, Novo Nordisk Revised 05/2026. Sections 1, 5.5, 12.1, 12.3 and Medication Guide.
  4. RYBELSUS® and OZEMPIC® (semaglutide) tablets Prescribing Information, Novo Nordisk Revised 1/2026. Sections 1, 2.3 and 12.3.
  5. FOUNDAYO™ (orforglipron) tablets Prescribing Information, Eli Lilly and Company Revised 07/2026. Highlights and Boxed Warning; sections 1, 2.2, 4, 7.1, 11 and 12.1–12.3.
  6. SAXENDA® (liraglutide) Prescribing Information, Novo Nordisk Revised 02/2026. Section 12.1.
  7. Frequently Asked Questions about Labeling for Prescription Medicines, U.S. FDA Content current as of 04/01/2024.
  8. Supplement approval letter, Ozempic® and Rybelsus® (semaglutide) tablets, NDA 213051/S-030, U.S. FDA Dated 01/30/2026. Renames Rybelsus® formulation R2 as Ozempic® tablets.
  9. Drucker DJ, Holst JJ. The expanding incretin universe: from basic biology to clinical translation. Diabetologia 2023;66(10):1765-1779 Peer-reviewed review. PMID 36976349.
  10. Accelerated Approval Program, U.S. FDA Content current as of 08/25/2026.
  11. Compounding and the FDA: Questions and Answers, U.S. FDA Content current as of 09/16/2025.
  12. Estimated Glomerular Filtration Rate (eGFR) and GFR Tests, MedlinePlus Accessed 20-10-2026.
  13. Hemoglobin A1C (HbA1c) Test, MedlinePlus Accessed 20-10-2026.
  14. Microalbumin Creatinine Ratio, MedlinePlus Accessed 20-10-2026.
  15. Sleep Apnea, MedlinePlus Accessed 20-10-2026.
  16. Prescription Medications to Treat Overweight & Obesity, NIDDK (NIH) Last reviewed June 2024.
  17. FDA Approves New Medication for Chronic Weight Management, U.S. FDA Content current as of 11/08/2023.
  18. FDA Approves Treatment for Serious Liver Disease Known as ‘MASH’, U.S. FDA Content current as of 08/15/2025.

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