Switching between Wegovy, Zepbound and Mounjaro: what the labels and studies say

What the labels say

A label is the legal prescribing information a maker files with the FDA. The Atlas searched the current labels for any text on switching from one GLP-1 medicine to another. Wegovy and Zepbound are the weight-loss brands. Mounjaro is the same medicine as Zepbound (tirzepatide) with a different approved use, and Ozempic is the same medicine as Wegovy (semaglutide). The brand and generic names page shows how the products relate, and Mounjaro vs Ozempic and Ozempic vs Wegovy compare what each label lists.

This summarizes label text for information. It is not a switching guide. Label text changes, so check the current label, and let a prescriber decide.

Using two GLP-1 medicines at once

The Wegovy label says that using it together with any other GLP-1 receptor agonist is not recommended. The Zepbound label says the same about other tirzepatide-containing products and any GLP-1 receptor agonist, and the Foundayo label says the same about another GLP-1 receptor agonist. Each says this in Section 1.

Apart from the Wegovy injection-to-tablet gap above, the labels do not say how long to wait between the last dose of one medicine and the first dose of another.

What no label gives: a matching dose

The Atlas found no label or randomized trial that gives a dose of one of these medicines that matches a dose of another. The two act differently (semaglutide on the GLP-1 receptor, tirzepatide on both the GIP and GLP-1 receptors), come in different dose steps and were tested in different trials. The head-to-head trial, SURMOUNT-5, compared people who started on one medicine or the other. It did not study people who switched.

One 2026 analysis used published type 2 diabetes trial results to model which dose pairs gave similar average weight loss, and it reported equivalence for some pairs. It is a modeling exercise on trial averages, not a trial of people switching. The Atlas does not repeat the pairs, because an average across trials is not a basis for choosing a dose. The microdosing page covers the related idea of staying on a fraction of a labeled dose.

What studies of people who switched found

The Atlas found no randomized trial of switching between Wegovy, Zepbound and Mounjaro. What exists is chart reviews, small studies and case reports. They describe what happened to the people who switched. They cannot show that switching caused the result, because people who switch differ from people who stay.

How common switching is, and why people do it

Switching is common in practice. The studies that measured reasons point to cost and coverage more than to medical ones.

Studies that have started

Several registered studies involve switching. None has posted results, and none compares switching among Wegovy, Zepbound and Mounjaro head to head.

Registry entries are the sponsors' descriptions and can change. A registered trial is not a result.

What people report

Switching is a regular topic in online communities, where people describe changes driven by cost or coverage, side effects or a stall in weight loss, and compare how each medicine felt.

None of this was measured, and the people who post are not a typical sample. It is here because switching is common, not because the posts show what works. The side effects, week by week page covers what labels and trials say about the early weeks on a medicine, and the paying page covers how coverage and cash prices work.

If you stop instead of switching

Some people stop one medicine without starting another. The weight regain page covers what trials found in that case, including the trials of stepping down to a lower dose or moving to a pill.

Quick answers

Can you switch from Wegovy to Zepbound?

Prescribers do move people between them, and data from Poland and the U.K. show it happens often. The Zepbound label has no text on switching from another medicine, and the Atlas found no randomized trial of it, so how to do it is a prescriber's decision.

Is there a Wegovy dose that equals a Zepbound dose?

No label or trial the Atlas found gives one. A 2026 modeling analysis of published type 2 diabetes trial results estimated which doses gave similar average weight loss, but it is not a guide to switching a person.

Are Mounjaro and Zepbound the same?

Both contain tirzepatide and are made by Eli Lilly. Mounjaro's U.S. label covers type 2 diabetes, and Zepbound's covers weight reduction and obstructive sleep apnea in adults with obesity. The brand and generic names page shows how the products relate.

Can you take two GLP-1 medicines at the same time?

The Wegovy, Zepbound and Foundayo labels each say, in Section 1, that using the medicine together with another GLP-1 receptor agonist is not recommended.

What does the Wegovy label say about switching from the injection to the tablets?

Section 2.5 covers it. For people on the 2.4 mg injection, it says to start the 25 mg tablet one week after stopping the injection. The Atlas reports the text for information. Your prescriber decides.

Has switching been tested in a trial?

Not between these medicines, as far as the Atlas found. A phase 3 trial of switching to an investigational monthly medicine started in September 2026, and an observational study of semaglutide-to-tirzepatide switching is registered. Neither has results.

Why do people switch?

In a sample of 288 people who stopped injectable semaglutide or tirzepatide, cost or insurance was the most common reason (47.6%), ahead of side effects (14.6%). A U.K. study found switching rose after a tirzepatide price increase.

Do people lose more weight after switching?

In one chart review, 61 people who switched from semaglutide to tirzepatide lost an average of 5.3% over 6 months, with people at a plateau losing more than non-responders. There was no comparison group, so it cannot say what staying put would have done.

Questions to ask

• If I switch, how long should I wait after my last dose, and why?
• Which dose would you start the new medicine at, and what is the plan for increasing it?
• What will change in my insurance coverage or cash cost if I switch?
• Do any of my other medicines need a closer look when my GLP-1 medicine changes?
• What would tell us the switch is working, and when do we check?
• Which side effects should I expect to feel again, and when should I call?

What is still unknown

• The Atlas found no randomized trial of switching between Wegovy, Zepbound and Mounjaro.
• No label or trial the Atlas found gives a dose of one medicine that matches a dose of another.
• The labels do not say how long to wait between the last dose of one medicine and the first dose of another. The only timing in them is Wegovy's gap between its own injection and tablets.
• The switching studies are small, retrospective or single cases, and none the Atlas found had a group that stayed on the first medicine for comparison.
• The Atlas found no study of whether side effects return when a new medicine is started, or whether tolerance carries over.
• Labels and registry entries change. The versions here were read in October 2026.