Plain-language definitions of the terms used across GLP-1 Cost Guide.

503A pharmacy

A state-licensed pharmacy that compounds medications for an individual patient under a patient-specific prescription, following USP <797> sterile-compounding standards. Regulated by the state board of pharmacy.

503B outsourcing facility

An FDA-registered facility that compounds in larger batches under full cGMP manufacturing standards and is subject to FDA inspection. Created by the 2013 Drug Quality and Security Act.

Advertised price

The "from" price a provider markets — usually the starter dose. Often lower than the true maintenance-dose price.

True maintenance price

The price you actually pay once titrated to a typical maintenance dose. The number that matters for budgeting.

Flat pricing

A pricing model where the monthly cost is held constant across the full dose titration, rather than rising with the dose.

Titration

The gradual increase of a GLP-1 dose over weeks to limit gastrointestinal side effects (e.g., tirzepatide 2.5→15 mg).

cGMP

Current Good Manufacturing Practice — the FDA framework governing drug manufacturing quality, required of 503B facilities.

USP <797>

The United States Pharmacopeia standard for sterile compounding, applicable to 503A pharmacies preparing injectables.

LegitScript

A third-party certification that audits healthcare merchants for legal and regulatory compliance; used by ad platforms and payment processors.

GLP-1 receptor agonist

A drug class (e.g., semaglutide) that mimics the GLP-1 gut hormone to reduce appetite, slow gastric emptying, and improve insulin response.

Dual GIP/GLP-1 agonist

A drug (tirzepatide) that activates both the GIP and GLP-1 receptors, associated with greater weight loss than GLP-1 alone.

Compounded medication

A medication prepared by a pharmacy for a specific patient or need; not FDA-approved. Distinct from brand-name FDA-approved products.

Enforcement discretion

A temporary FDA policy of not acting against compounders during a shortage; ended for GLP-1s in 2025.

503B bulks list

The FDA list of bulk drug substances 503B facilities may compound from; the FDA proposed excluding GLP-1s in April 2026.