GLP-1 glossary: 25 terms, each with its source

A state-licensed pharmacy compounding under section 503A of the federal Food, Drug, and Cosmetic Act: for an individual patient, on a prescription, and overseen mainly by its state board of pharmacy.

"The drug product is compounded for an individual patient based on receipt of a prescription."

FDA, 4/1/2026 compounding update, read Oct 3, 2026

A compounder registered with FDA under section 503B that may make larger batches; FDA inspects it on a risk-based schedule.

"Outsourcing facilities are a category of compounders established in 2013 by the Drug Quality and Security Act. Outsourcing facilities are inspected by FDA according to a risk-based schedule and are subject to increased quality standards."

FDA, Compounding and the FDA: Questions and Answers, read Oct 3, 2026

What leaves your account each month: the medication plus any membership fee. Every ranking on this site uses it.

PriceTracker GLP-1 methodology, read Oct 3, 2026

FDA's letter confirming a company corrected the violations in a warning letter, issued only after FDA verifies the fixes.

"FDA may issue a Warning Letter close-out letter ("close-out letter") once the Agency has completed an evaluation of corrective actions undertaken by a firm in response to a Warning Letter."

FDA, About Warning and Close-Out Letters, read Oct 3, 2026

A drug mixed by a pharmacy or outsourcing facility rather than made by the approved manufacturer. Compounded GLP-1s are not FDA-approved.

"Compounded drugs are not FDA-approved. This means that FDA does not verify the safety, effectiveness or quality of compounded drugs before they are marketed."

FDA, Compounding and the FDA: Questions and Answers, read Oct 3, 2026 · Is compounded semaglutide still legal?

FDA's term for a compounded drug with the same active ingredient, a similar strength and the same route as an approved drug; 503A pharmacies may not make these regularly or in inordinate amounts.

"FDA has stated, at this time, it does not intend to take action against a compounder for compounding a drug product that is essentially a copy of a commercially available drug product regularly or in inordinate amounts if the compounder fills four or fewer prescriptions of that compounded drug product during a calendar month."

FDA, 4/1/2026 compounding update, read Oct 3, 2026

The list of observations FDA investigators hand a company at the end of an inspection. It is not a final agency decision.

"An FDA Form 483 is issued to firm management at the conclusion of an inspection when an investigator(s) has observed any conditions that in their judgment may constitute violations of the Food Drug and Cosmetic (FD&C) Act and related Acts."

FDA, Form 483 Frequently Asked Questions, read Oct 3, 2026

A drug your plan leaves off its formulary, the list of drugs it covers, so it pays nothing toward it without an exception.

"A list of prescription drugs covered by a prescription drug plan or another insurance plan offering prescription drug benefits. Also called a drug list."

HealthCare.gov glossary, formulary, read Oct 3, 2026 · Insurance coverage checker

Glucose-dependent insulinotropic polypeptide, the second gut hormone that raises insulin after eating. Tirzepatide acts on both the GIP and GLP-1 receptors.

"The incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) have their main physiological role in augmenting insulin secretion after their nutrient-induced secretion from the gut."

Nauck and Meier, PubMed 34310013, read Oct 3, 2026

Glucagon-like peptide-1, a hormone the gut releases after a meal that lowers blood sugar and signals fullness. GLP-1 drugs (semaglutide, tirzepatide, orforglipron) act on its receptor.

"glucagon-like peptide-1 (GLP-1), a blood glucose-lowering hormone that is released from enteroendocrine L cells of the distal intestine after the ingestion of a meal."

Leech et al., PubMed 21782840, read Oct 3, 2026 · What is GLP-1?

A private certification online pharmacies and telehealth sellers apply for to show compliance; ad platforms and payment processors use it.

"Learn how LegitScript Certification opens doors to advertising and payment processing while proving your compliance."

LegitScript, Healthcare Certification, read Oct 3, 2026 · How to check a GLP-1 seller

The dose you stay on once titration ends. It is usually the most expensive step in a self-pay price ladder.

"The recommended maintenance dosage of WEGOVY tablets is 25 mg orally once daily."

Wegovy prescribing information, read Oct 2, 2026

A form of fatty liver disease with inflammation. Wegovy is approved to treat it in certain adults.

"nonalcoholic steatohepatitis, or NASH (also referred to as metabolic dysfunction-associated steatohepatitis, or MASH)"

NIDDK, NAFLD and NASH, read Oct 3, 2026

National Average Drug Acquisition Cost: CMS's survey-based figure for what retail pharmacies pay to buy a drug. It is a pharmacy cost, not the price a patient pays.

"We update the National Average Drug Acquisition Cost (NADAC) data and comparison data weekly."

Medicaid.gov, NADAC, read Oct 3, 2026

Eli Lilly's once-daily GLP-1 pill, sold as Foundayo, first approved in the US in 2026 for weight management.

"Initial U.S. Approval: 2026"

Foundayo prescribing information (DailyMed), read Oct 3, 2026 · Foundayo prices

Obstructive sleep apnea, where the airway closes repeatedly during sleep. Zepbound is approved to treat moderate to severe OSA in adults with obesity.

"Obstructive sleep apnea, also called OSA, happens when your upper airway becomes blocked many times while you sleep."

NHLBI, Sleep apnea, read Oct 3, 2026 · Zepbound for sleep apnea

A manufacturer program that gives medicine free to people under an income limit. Neither Lilly Cares nor Novo Nordisk's program lists a weight-loss GLP-1.

"These income limits are 300% (Group 1 Medications), 400% (Group 2 Medications), and 500% (Group 3 & 4 Medications) of 2026 Federal Poverty Guidelines."

Lilly Cares Foundation, how to apply, read Oct 3, 2026 · Patient assistance checker

Paying several months up front for a lower monthly rate: on a 12-month plan, twelve months of the advertised price leave your account on day one.

PriceTracker GLP-1, prepay discounts, read Oct 3, 2026 · How many headline prices need a prepay

Your plan's sign-off before it will pay for a prescription. Most plans that cover GLP-1s for weight loss require it.

"Approval from a health plan that may be required before you get a service or fill a prescription in order for the service or prescription to be covered by your plan."

HealthCare.gov glossary, read Oct 3, 2026 · If your GLP-1 is denied

A manufacturer offer that lowers your copay when commercial insurance covers the drug, up to a monthly cap. Government plans such as Medicare and Medicaid are excluded.

"Pay as little as $25, subject to a maximum savings of $100/month. Government beneficiaries excluded."

NovoCare Pharmacy, Wegovy terms, read Oct 3, 2026 · Every savings card

The GLP-1 drug in Wegovy, Ozempic and Rybelsus, made by Novo Nordisk; injected weekly or taken as a daily tablet.

"Semaglutide is a GLP-1 analogue with 94% sequence homology to human GLP-1."

Ozempic prescribing information (DailyMed), read Oct 3, 2026 · Cheapest semaglutide

A plan rule that you try a cheaper drug first before it covers a more expensive one.

"Step therapy is a type of prior authorization that requires you first to try a certain, less expensive drug on the plan’s drug list that’s been proven effective for most people with your condition before you can move up a “step” to a more expensive drug."

Medicare.gov, drug plan coverage rules, read Oct 3, 2026

The drug in Zepbound and Mounjaro, made by Eli Lilly; it acts on both the GIP and GLP-1 receptors and is injected weekly.

"Tirzepatide is a GIP receptor and GLP-1 receptor agonist."

Mounjaro prescribing information, read Oct 3, 2026 · Cheapest tirzepatide

Starting a drug at a low dose and raising it in steps, usually every four weeks, to let the body adjust. GLP-1 labels set the schedule.

"The recommended starting dosage of WEGOVY tablets is 1.5 mg taken orally once daily."

Wegovy prescribing information (DailyMed), read Oct 3, 2026 · Titration schedule and cost

FDA's formal notice to a company about what it believes are significant violations. It is an allegation, not a court finding.

"When FDA identifies what it believes are significant violation(s) of federal requirement(s), FDA notifies the appropriate party. This notification is often in the form of a Warning Letter."

FDA, About Warning and Close-Out Letters, read Oct 3, 2026