Ozempic vs Wegovy vs Mounjaro vs Zepbound: the brand decoder

Four brand names dominate the GLP-1 conversation, but they trace back to only two molecules. Ozempic and Wegovy are both semaglutide. Mounjaro and Zepbound are both tirzepatide. The split inside each pair is by approved use — one brand carries the diabetes indication, the other the weight-management indication — not by a different drug.

This page is a decoder, not advice. It contains no doses or schedules and is not a substitute for a prescriber who knows your history.

What is the difference between Ozempic, Wegovy, Mounjaro, and Zepbound?

They are four brands built from two active ingredients. Semaglutide is sold as Ozempic (approved for type 2 diabetes) and as Wegovy (approved for chronic weight management). Tirzepatide is sold as Mounjaro (type 2 diabetes) and as Zepbound (chronic weight management). So the meaningful first question is never “which brand is strongest” but “which molecule is this, and for which approved use.”

Brand	Molecule	Mechanism	Primary approved use (US)	Headline obesity-trial weight loss
Ozempic	Semaglutide	GLP-1 receptor agonist (single incretin)	Type 2 diabetes; cardiovascular-risk reduction in type 2 diabetes with heart disease	Not an obesity drug — see Wegovy for the weight figure
Wegovy	Semaglutide	GLP-1 receptor agonist (single incretin)	Chronic weight management; also CV-risk reduction and MASH (liver) in eligible adults	−14.9% mean over 68 weeks (STEP 1)
Mounjaro	Tirzepatide	GLP-1 + GIP receptor agonist (dual incretin)	Type 2 diabetes	Not an obesity drug — see Zepbound for the weight figure
Zepbound	Tirzepatide	GLP-1 + GIP receptor agonist (dual incretin)	Chronic weight management; also moderate-to-severe obstructive sleep apnea in obesity	up to −22.5% mean over 72 weeks (SURMOUNT-1, highest dose)

The weight-loss figures belong to the weight-management brands (Wegovy, Zepbound) at their obesity doses. The diabetes brands (Ozempic, Mounjaro) are studied and approved chiefly for blood-sugar control; people often lose weight on them, but the headline obesity percentages above come from the Wegovy and Zepbound trial programs, not from the diabetes-dose studies. Quoting a Wegovy number for “Ozempic” is a common and misleading shortcut.

Is Ozempic the same as Wegovy?

Same molecule (semaglutide), different product. They share the active ingredient but are approved for different purposes and reach different maximum doses, and they are not interchangeable on a prescription. This is an instance of the book’s “same molecule, different product” principle: identical chemistry does not make two products the same in approved use, dosing ceiling, or how they should be prescribed and supervised.

Is Mounjaro the same as Zepbound?

Yes, both are tirzepatide. Mounjaro is the type 2 diabetes brand; Zepbound is the chronic-weight-management brand (and is also approved for moderate-to-severe obstructive sleep apnea in adults with obesity). Same molecule, two brand identities tied to two approved indications.

Why do tirzepatide brands tend to show larger weight loss?

Tirzepatide is a dual agonist: it activates the GLP-1 receptor and the GIP receptor, whereas semaglutide acts on GLP-1 alone. On the Evidence Ladder, the size of the effect for each drug is established — it rests on several large randomized trials of approved drugs used as approved. The most direct comparison, SURMOUNT-5, randomized adults with obesity to one drug or the other for 72 weeks and reported −20.2% with tirzepatide versus −13.7% with semaglutide. That head-to-head is a single, open-label trial, so the comparative claim sits at supported but limited rather than fully settled — strong enough to take seriously, not a final verdict. Whether the extra effect is the GIP target itself or a dose-response effect remains an open mechanistic question.

Frequently asked questions

Are any of these the same as compounded “semaglutide” or “tirzepatide” sold online? No. The brand names above are FDA-approved, manufactured products. A vial labeled with the same molecule name from an unregulated source is not the same product in sterility, concentration accuracy, or accountability. Same molecule, different product.

Is there a pill version? Both molecules began as weekly injections. An oral semaglutide for weight management has since been approved. Approved formulations change over time — confirm the current options and labeling with a clinician or pharmacist rather than assuming.

Which one is “best”? There is no single answer. The right choice depends on the approved indication you actually have (diabetes vs weight management vs sleep apnea), your medical history, tolerance, and access — a clinical decision, not a ranking.

Is retatrutide one of these? No. Retatrutide is a separate, investigational triple agonist that is not FDA-approved and is still in trials. It is not Ozempic, Wegovy, Mounjaro, or Zepbound.

Questions to ask a clinician

• Given my diagnosis, which approved indication applies to me — diabetes, weight management, or another?
• Is the molecule that fits my situation semaglutide or tirzepatide, and why?
• What does the evidence say about the benefit I can realistically expect, versus the trial averages?
• How will we weigh tolerance and side effects against the size of the expected effect?
• If cost or supply is a barrier, what legitimate, supervised options exist?

Red flags / when to seek care

The brand you are on does not change the warning signs. Across both molecules, contact a clinician promptly — and seek urgent care for the severe versions — if you have:

• Severe, persistent abdominal pain, especially radiating to the back with repeated vomiting (a possible sign of pancreatitis).
• Upper-right abdominal pain, fever, or yellowing of the skin or eyes (possible gallbladder disease).
• A distended belly with vomiting and no bowel movements (possible bowel obstruction).
• Signs of dehydration from prolonged vomiting or diarrhea.

A product bought outside the regulated supply chain carries these same risks with none of the oversight or recourse. If something feels genuinely wrong in your body, that is a reason to call — not a claim to grade.