Zepbound and Ozempic are different drugs, approved for different things

Four brands, two drugs

These four names cover two active ingredients. Ozempic and Wegovy are both semaglutide. Mounjaro and Zepbound are both tirzepatide. Within each pair the molecule is the same and the approval is not, which is why one of the two is sold for diabetes and the other for weight.

How the two molecules differ in class and in what each label was built to prove is on semaglutide and tirzepatide, as the labels describe them. Whether either of them is insulin is its own question, and the answer is no.

What each one is approved to do

An approval is not a suggestion about who a drug might suit. It is the use the FDA reviewed the evidence for, and it decides what the manufacturer may sell the product to do.

Ozempic and Mounjaro are diabetes labels. Both are indicated as an adjunct to diet and exercise to improve glycemic control in type 2 diabetes, and both carry a heart-risk indication on top of it. Neither label carries a weight-loss indication, and neither prints a weight-loss claim in its indications section.

Wegovy and Zepbound are weight labels. Both are indicated, in combination with a reduced-calorie diet and more physical activity, to reduce excess body weight and maintain the reduction long term. Each then carries one indication the other does not: Wegovy adds cardiovascular risk reduction and noncirrhotic MASH with moderate to advanced fibrosis, and Zepbound adds moderate to severe obstructive sleep apnea in adults with obesity.

The dose ceilings differ too, and not by a little. Ozempic’s maximum is 2 mg a week; Wegovy’s injection goes to 7.2 mg; both tirzepatide brands stop at 15 mg. The ladders each label sets to get there are on the dose escalation schedules, and what Zepbound’s own trials reported at each maintenance dose is on Zepbound at 5, 10 and 15 mg.

What the labels say about swapping and stacking

Both weight labels carry a limitation of use, and it is the closest any of these documents comes to answering whether one can be taken instead of the other.

Zepbound: “Coadministration with other tirzepatide-containing products or with any glucagon-like peptide-1 (GLP-1) receptor agonist is not recommended.” Wegovy: “Concomitant use of WEGOVY (semaglutide) tablets or WEGOVY (semaglutide) injection with other semaglutide-containing products or with any other GLP-1 receptor agonist is not recommended.”

Read strictly, those rules are about taking two at once, and every one of these four products is a GLP-1 receptor agonist. On switching from one to the other, the labels say nothing at all: no equivalence table, no conversion, no starting dose for someone arriving from another brand. Each label starts its own patients at its own lowest dose and climbs from there, which is a question for the prescriber rather than something a reader can settle from the documents.

One thing the tirzepatide pair does share is the practical detail. Mounjaro and Zepbound carry the same missed-dose window, the same storage rules and the same injection instructions, set out on missed dose rules, refrigeration and storage and where and how to inject them.

Sources

See the providers

Sellers list by molecule more often than by brand. The boards show who sells each one and what each seller publishes about the price.

• Semaglutide providersprovider board

  Readers who have settled on semaglutide and are choosing who to buy it from.

• Tirzepatide providersprovider board

  Readers who have settled on tirzepatide and are choosing who to buy it from.

More, read from the same labels

• Semaglutide vs tirzepatidereading the label

  What the four FDA-approved labels say each molecule is, what each is approved to treat, and where the two differ.

• How they workreading the label

  The receptor each molecule switches on, what the labels say that does to appetite, blood sugar and the stomach, and why one dose lasts a week.

• Is Ozempic insulin?reading the label

  What the Ozempic label calls semaglutide, how that differs from insulin, and where insulin appears on these labels as a separate medicine.

• Dose escalation schedulesreading the label

  The starting dose, the escalation interval and the maximum dose each label sets, and why they are not interchangeable.

• Side effect ratesreading the label

  What each label reports for nausea, vomiting, diarrhea and constipation — and the sentence every label prints above those numbers.

• Hair lossreading the label

  Which labels report hair loss, the rate against placebo where a trial measured it, and why two of them put no number on it.

• Fatigue and tirednessreading the label

  Which labels list fatigue, the rate against placebo where a trial measured it, and what each label counts as fatigue.

• Missed dose rulesreading the label

  The window each label gives for a late dose, and the minimum gap it requires when the injection day changes.

• Drug interactionsreading the label

  Insulin and sulfonylureas, oral medications, and the oral-contraceptive precaution that appears on two of these four labels and not the other two.

• Buying one onlinereading the label

  The agency's own warning signs for a telehealth GLP-1 seller, its 28-day vial rule, and what it says about drugs that arrive warm.

• Zepbound by dosereading the label

  What each Zepbound dose achieved in the trials printed in its label, what the label says about choosing a maintenance dose, and what the higher doses cost in side effects.

• Zepbound at 3 monthsreading the label

  What the Zepbound label reports and at which weeks it reports it, and where the label's own dose schedule puts a reader at three months.

• Injecting tirzepatidereading the label

  The injection sites, the rotation rule and the steps for the single-dose pen, the KwikPen and the vial and syringe, exactly as the FDA-approved Instructions for Use give them.

• Refrigeration and storagereading the label

  How cold each pen is kept, how many days it can spend at room temperature, and what the labels say about heat and freezing.

• Who should not take onereading the label

  The boxed warning every one of these labels carries, the two contraindications, and which warnings appear on which product.