This market runs on vocabulary — trial acronyms in the ads, legal jargon in the fine print, community slang in the forums. Every term below gets a plain-English definition; the deep treatment lives in the linked journal files and medication references.
Molecules and products
GLP-1 — Glucagon-like peptide-1: a gut hormone that boosts satiety and insulin response; also shorthand for the entire drug class that mimics it.
GIP — Glucose-dependent insulinotropic polypeptide — the second incretin hormone; tirzepatide’s added target.
Glucagon (receptor) — A third hormonal target, used by retatrutide; raises energy expenditure alongside appetite effects.
Incretin — Umbrella term for gut hormones (GLP-1, GIP) released after eating that shape insulin and appetite.
Amylin — A satiety hormone co-released with insulin; cagrilintide is its long-acting analog.
Semaglutide — GLP-1 receptor agonist sold as Ozempic, Wegovy, and Rybelsus; ~14.9% average loss in STEP 1.
Tirzepatide — Dual GIP/GLP-1 agonist sold as Mounjaro and Zepbound; up to 20.9% average loss in SURMOUNT-1.
Liraglutide — First-generation daily GLP-1 (Saxenda, Victoza); ~8% average loss; now available as a generic.
Retatrutide — Investigational triple agonist; ~24% average loss in phase 2; not approved, not purchasable.
Orforglipron — Investigational once-daily oral small-molecule GLP-1; no food or water restrictions in trials.
CagriSema — Investigational cagrilintide + semaglutide combination; ~22.7% company-reported topline in REDEFINE-1.
Ozempic — Semaglutide branded for type 2 diabetes (0.5–2 mg weekly); famous off-label, but not a weight-loss label.
Wegovy — Semaglutide 2.4 mg branded for weight management and cardiovascular risk reduction.
Rybelsus — The only FDA-approved oral GLP-1: daily semaglutide tablets with a strict empty-stomach ritual.
Zepbound — Tirzepatide branded for weight management and, since December 2024, obstructive sleep apnea.
Mounjaro — Tirzepatide branded for type 2 diabetes.
Saxenda — Liraglutide 3 mg branded for weight management; daily injection.
Mechanism and pharmacology
Receptor agonist — A molecule that activates a receptor the way the natural hormone would.
Dual / triple agonist — Drugs hitting two (tirzepatide) or three (retatrutide) receptor targets at once.
Half-life — Time for drug levels to fall by half — roughly 5 days for tirzepatide, ~7 for semaglutide; the basis of weekly dosing.
Bioavailability — Fraction of a dose that reaches circulation; ~1% for oral semaglutide, which is why its ritual matters.
SNAC — The absorption enhancer in Rybelsus that lets a peptide survive the stomach at all.
Delayed gastric emptying — The class’s slowed-stomach effect — source of satiety, nausea, reflux, and drug-absorption interactions alike.
Food noise — Community term for intrusive food preoccupation; its quieting is the most-reported subjective GLP-1 effect.
Set point — The weight range the body defends via hunger and metabolism — the force behind post-discontinuation regain.
Trials and endpoints
STEP / SURMOUNT / SURPASS / SUSTAIN / PIONEER — The pivotal trial programs: semaglutide weight, tirzepatide weight, tirzepatide diabetes, semaglutide diabetes, oral semaglutide.
SELECT — The landmark trial showing semaglutide 2.4 mg cut major cardiovascular events 20% in people without diabetes.
FLOW — Semaglutide kidney-outcomes trial in diabetic kidney disease; basis of the CKD indication.
SCALE — Liraglutide’s weight-management program (~8% average loss).
MACE — Major adverse cardiovascular events — heart attack, stroke, cardiovascular death — the SELECT endpoint.
A1c — Three-month average blood-glucose marker; the core diabetes endpoint.
BMI — Body mass index; the (imperfect) eligibility gate most labels and insurers use.
Topline results — Company-announced summary numbers released before peer review — treat as provisional.
Clinical phases — Phase 2 = smaller dose-finding trials; phase 3 = large confirmatory ones. Phase 3 means routinely land below phase 2 headlines.
Safety terms
Boxed warning — The FDA’s strongest label warning — here, rodent thyroid C-cell tumors of unknown human relevance.
MTC / MEN 2 — Medullary thyroid carcinoma and the syndrome that predisposes to it; personal or family history contraindicates the class.
Pancreatitis — Pancreas inflammation — a class caution with severe-abdominal-pain warning signs, unconfirmed as a causal excess in the big trials.
Cholelithiasis — Gallstones — a real, rapid-weight-loss-linked class risk.
Gastroparesis — Severely delayed stomach emptying; the labels caution against use in severe cases.
Ileus — Intestinal paralysis — added to labels from postmarketing reports.
Telogen effluvium — Temporary shedding-phase hair loss that can follow rapid weight loss; typically self-resolving.
Hypoglycemia — Low blood sugar — the main combination risk with insulin or sulfonylureas.
Contraindication — A condition under which a drug should not be used at all.
Dosing and practice
Titration — The stepwise dose-escalation schedule that manages side effects; rushing it is the classic error.
Maintenance dose — The dose you stay on long-term — the one honest cost math must price.
Microdosing — Marketing term for below-label dosing; discussed in our evidence file, promised outcomes are not trial-backed.
Washout — Time for a drug to clear — weeks for these half-lives; drives pregnancy-planning and surgery guidance.
Missed-dose window — Label rules for late doses: within 4 days (tirzepatide) or 5 days (Ozempic); otherwise skip, never double.
ODT / sublingual — Dissolving-tablet and under-the-tongue formats; compounded versions lack published outcome trials.
Beyond-use date (BUD) — The compounded-product expiry assigned by the pharmacy — typically far shorter than manufactured shelf life.
Cold chain — Refrigerated custody from factory to fridge; breaks (like freezing) can ruin the drug.
Sarcopenia — Age-related muscle loss — the reason lean-mass preservation and protein targets matter during rapid loss.
Market, legal, and pricing
Compounding — Pharmacy-made drug versions; legal lanes narrowed sharply once the FDA shortage declarations ended.
503A / 503B — The two compounding regimes: patient-specific pharmacies vs FDA-registered outsourcing facilities with tighter standards.
“Personalization” — The contested rationale for continued compounded GLP-1s — tweaked doses or added ingredients; legally gray, actively litigated.
FDA shortage list — The registry whose GLP-1 entries once permitted mass compounding; their resolution is the market’s legal fault line.
Gray market — Unregulated “research” peptide vendors selling unverified vials — no prescriber, no pharmacy, no recourse.
Research use only — A label meaning not for human use — on a consumer site, a confession.
COA — Certificate of analysis — third-party test results; necessary but not sufficient evidence of quality.
LegitScript / NABP — Certification bodies for legitimate online pharmacies; their absence is a checklist red flag.
Teaser pricing — An advertised entry price that balloons at maintenance dose — anatomy dissected in our journal.
Rate lock — A contractual promise your price won’t rise at renewal or dose change — the structural antidote to teasers.
Prior authorization — Insurer pre-approval paperwork; where most coverage attempts die or succeed.
Formulary / step therapy — An insurer’s covered-drug list, and its try-cheaper-first rules.
Savings card — Manufacturer copay assistance for the commercially insured; government plans excluded.
Self-pay channel — Manufacturer direct cash programs (LillyDirect vials, NovoCare pharmacy) that undercut list price.
Material connection — A financial relationship between a reviewer and a reviewed company — ours with NexLife is disclosed on every commercial page.
Missing a term?
Tell us at corrections — the glossary grows with the ledger.