Weight & Metabolic Health · Reference
GLP-1 and Weight-Loss Medication Terms, Explained in Plain English
The vocabulary of medical weight loss, defined precisely — because half the confusion in this market is terminology used loosely, and some of it is used loosely on purpose.
The medications
GLP-1 (glucagon-like peptide-1) receptor agonist
A class of medications that mimic a natural gut hormone involved in appetite and blood-sugar regulation. Originally developed for type 2 diabetes; now the dominant class of prescription weight-loss medication.
Semaglutide
The GLP-1 molecule in Wegovy (approved for weight management) and Ozempic (approved for diabetes). In its pivotal weight trial it produced an average 14.9% body-weight loss over 68 weeks (STEP 1).
Tirzepatide
The dual-hormone (GLP-1/GIP) molecule in Zepbound (weight) and Mounjaro (diabetes). Averaged up to 20.9% loss over 72 weeks in SURMOUNT-1, and beat semaglutide in the 2025 head-to-head trial. Comparison: Wegovy vs Zepbound.
Branded vs generic
There is no FDA-approved generic semaglutide or tirzepatide — anything sold as a cheaper "version" of these drugs is compounded (below), not generic. This distinction is the single most misused piece of vocabulary in the market.
The compounding vocabulary
Compounded medication
A drug mixed by a pharmacy rather than the original manufacturer. Legal in specific circumstances, but compounded drugs are not FDA-approved — no regulator has reviewed that specific product's safety, effectiveness or quality. Full context: compounded vs branded in 2026.
503A pharmacy
A traditional compounding pharmacy making patient-specific preparations from individual prescriptions. The lane that remains legal for GLP-1s requires documented clinical need — a dose or formulation no approved product offers.
503B outsourcing facility
A facility allowed to compound at commercial scale. The FDA has moved to exclude GLP-1s from this pathway entirely — the regulatory change closing large-scale GLP-1 compounding.
"Personalized dosing"
A marketing phrase some telehealth companies use to position compounded GLP-1s inside the patient-specific exemption. Sometimes clinically genuine; often a workaround. If a service's "personalization" applies to every customer identically, it's positioning, not medicine.
The treatment vocabulary
Titration / dose escalation
The scheduled increase from a low starting dose to the maintenance dose over several months, designed to manage gastrointestinal side effects. Why "how fast does it work" has a slow honest answer: the real timelines.
Maintenance dose
The ongoing dose after titration. Note that trial results are measured at 68–72 weeks — and that stopping typically leads to substantial regain (SURMOUNT-4), which is why clinicians treat this as chronic-disease management.
Telehealth intake
The online health questionnaire and clinician review that precede a prescription. Depth of intake is the best proxy for a service's medical seriousness — what a legitimate intake looks like.
The marketing vocabulary (read defensively)
"Doctor-approved" / "physician-backed"
Legally near-meaningless phrases. What matters is whether a licensed clinician reviews your health history and manages your dosing.
"Clinically proven"
Check what was proven, on whom, and for how long — the honest numbers live in the trials (all key statistics, sourced). The FTC's false-claims guide is the reference for phrases that should end a conversation.