Plain-language definitions of terms you may encounter with GLP-1 medications.
GLP-1Glucagon-like peptide-1. A naturally occurring hormone produced in the small intestine that stimulates insulin release in response to food, slows gastric emptying, and signals satiety. GLP-1 receptor agonist medications mimic or enhance this hormone's effects.GLP-1 Receptor AgonistA class of prescription medications that bind to and activate GLP-1 receptors in the body. These drugs are used in the management of type 2 diabetes and, in some formulations, for chronic weight management. Examples include semaglutide, liraglutide, and tirzepatide (though tirzepatide is technically a dual GLP-1/GIP agonist).GIPGlucose-dependent insulinotropic polypeptide. Another incretin hormone similar in some functions to GLP-1. Some newer medications target both GLP-1 and GIP receptors simultaneously (dual agonists).AgonistA substance that binds to a receptor and activates it. A GLP-1 receptor agonist activates GLP-1 receptors, producing effects similar to natural GLP-1.IncretinA class of hormones released from the gut in response to food intake that stimulate insulin secretion. GLP-1 and GIP are both incretin hormones.TitrationThe process of gradually increasing a medication's dose over time according to a defined schedule. Most GLP-1 medications begin at a low dose and are titrated upward over weeks to months to allow the body to adjust and to help manage side effects.Prescribing InformationThe official FDA-approved document for a prescription drug, also called the package insert, full prescribing information (PI), or drug label. It contains comprehensive information on the drug's approved uses, dosing, contraindications, warnings, side effects, and storage requirements. Your pharmacist can provide a copy.FormularyA list of medications covered by an insurance plan, typically organized by tier. Whether your specific GLP-1 is on your plan's formulary — and what tier it is on — determines your coverage and out-of-pocket cost.Prior Authorization (PA)A requirement from your health insurer that your prescriber obtain approval before they will cover a specific medication. Many GLP-1 medications require prior authorization. See our guide on how prior authorization works.Patient Assistance Program (PAP)A program operated by a drug manufacturer that provides free or reduced-cost medication to qualifying patients who cannot afford it. Eligibility typically depends on income and insurance status.Copay Savings CardA manufacturer-sponsored program that reduces a patient's out-of-pocket cost for a specific medication. Most copay cards are available only to patients with commercial insurance — not Medicare, Medicaid, or other government coverage.ContraindicationA condition or factor that makes a medication inadvisable for a specific patient. For example, some GLP-1 medications are contraindicated in patients with a personal or family history of certain thyroid conditions. Your prescriber and the prescribing information for your specific drug list relevant contraindications.Sharps ContainerA puncture-resistant, leak-proof container designed for the safe disposal of used needles, syringes, and pen needles. FDA-cleared sharps containers meet federal safety standards.Cold ChainThe uninterrupted series of refrigerated storage and transport conditions required to maintain a temperature-sensitive medication's integrity from manufacture to patient use. Many injectable GLP-1s require cold-chain storage before first use.In-Use PeriodThe number of days after first use that an injectable pen can be used and the storage conditions that apply during that period. For some GLP-1 pens, the in-use period allows room-temperature storage even though the unopened pen requires refrigeration. This varies by medication — check your specific drug's labeling.FDA ApprovalAuthorization from the U.S. Food and Drug Administration that a drug is safe and effective for a specific approved use (indication). GLP-1 medications may be approved for type 2 diabetes, for chronic weight management, or for both — depending on the specific formulation and brand.Off-Label UseUse of a medication for a purpose, population, or dose not specified in its FDA approval. Prescribers can legally prescribe medications off-label. This is a conversation to have with your prescriber if applicable to your situation.BiosimilarA biological medication that is highly similar to an already-approved reference biologic, with no clinically meaningful differences. As some GLP-1 medications approach the end of their patent periods, biosimilars may become available.