Switching GLP-1 drugs: no FDA label gives a dose conversion
There is no published milligram-for-milligram conversion between semaglutide and tirzepatide. We read all six labels looking for one. The only switching instruction any of them carries is inside the Wegovy label, and it covers moving between Wegovy's own injection and tablet. Everything else is a prescriber's judgment, which is why a switch usually restarts near the bottom of the new ladder.
Where the new ladder starts
Both tirzepatide labels name one starting dosage and make no exception for a patient arriving from another GLP-1. Zepbound is explicit that its 2.5 mg dose is for treatment initiation and is not approved as a maintenance dosage.
| What the label says | Wegovy injection | Zepbound |
|---|---|---|
| Starting dose | 0.25 mg, weeks 1 to 4 | 2.5 mg for 4 weeks |
| How it climbs | 0.5 mg weeks 5 to 8, 1 mg weeks 9 to 12, 1.7 mg weeks 13 to 16, maintenance from week 17 | To 5 mg after 4 weeks, then 2.5 mg increments after at least 4 weeks on the current dose |
| Maintenance | 1.7 mg or 2.4 mg, with 2.4 mg marked recommended | 5 mg, 10 mg or 15 mg. For sleep apnea, 10 mg or 15 mg |
| Maximum | 7.2 mg weekly | 15 mg weekly |
| If you miss one | Take it if the next scheduled dose is more than 2 days away. Skip it if the next dose is less than 2 days away, and resume on the regular day. | Within 4 days (96 hours), take it. Past 4 days, skip it and take the next dose on the regular day. |
| Moving your dosing day | The label says the time of day and the injection site can change without a dosage modification. | Allowed if at least 3 days (72 hours) separate the two doses. |
| A step you cannot tolerate | “If patients do not tolerate a dose during dosage escalation, consider delaying dosage escalation for 4 weeks.” | “If patients do not tolerate a maintenance dosage, consider a lower maintenance dosage.” Four weeks is written as a minimum. |
| Coming back after a gap | If 2 or more consecutive doses are missed, the label says to reinitiate dosage escalation at a lower dosage. It does not name which lower dosage. | The label says nothing about restarting. |
The one switching instruction that exists
The Wegovy label carries a switching section and it covers Wegovy's own two forms. From the 2.4 mg injection, wait one week then start the 25 mg tablets. From the 25 mg tablets, start the 2.4 mg injection the next day. For a patient who cannot tolerate the 25 mg tablet, the label says to consider the 1.7 mg injection instead.
That is the whole of it across six labels. Nothing published converts semaglutide milligrams to tirzepatide milligrams, which means anyone showing you a conversion table built one.
What the switch costs
A switch changes the molecule, the program and usually the price, and it often resets a prior authorization, because a payer approves a named drug rather than a category. Our prior-authorization letter templatesare written to the payer's own published criteria. The chart prices every program at its ongoing maintenance cost, so you are comparing maintenance price against maintenance price.
Compare every program at its maintenance price →
How to switch programs without losing dose continuity →
Frequently asked questions
What tirzepatide dose equals 1 mg of semaglutide?
No FDA label answers that, and neither will we. There is no published equivalence between the two molecules. A prescriber moving you across is using clinical judgment, and the tirzepatide labels both start at 2.5 mg for everybody, which is why a switch usually restarts near the bottom of the new ladder.
Do I have to start the new drug at the bottom of its ladder?
The Zepbound and Mounjaro labels give one starting dosage, 2.5 mg once weekly, and Zepbound says plainly that the 2.5 mg dosage is for treatment initiation and is not approved as a maintenance dosage. Neither label carries an exception for someone arriving from another GLP-1.
Is there any switching instruction on any label?
One. The Wegovy label covers moving between its own two forms: from the 2.4 mg injection, wait one week then start 25 mg tablets; from 25 mg tablets, start the 2.4 mg injection the next day; and for a patient who cannot tolerate the 25 mg tablet, consider the 1.7 mg injection instead.
Will my prior authorization carry over?
Not automatically. A prior authorization is approved against a named drug, so a switch to a different molecule generally needs a new one. Our prior-authorization letter templates are written to the payer's own published criteria.
A switch between molecules is a prescribing decision and no page can make it for you. Take the ladder and the price to the appointment.
Sources
Evidence checked August 31, 2026
Each clinical claim above links to the document it came from, so you can read the source instead of trusting us. GLP Chart has no medical reviewer, and does not borrow a name for one. What that means.
- The only switching instruction on any of the six labels: moving between the Wegovy injection and the Wegovy tablet, in both directions, and the 1.7 mg alternative for a patient who cannot tolerate the 25 mg tabletFDA prescribing information for Wegovy, injection and tablets (DailyMed, revised June 2026)
- The Zepbound starting dosage a switcher restarts on, and the sentence that the 2.5 mg dose is for initiationFDA prescribing information for Zepbound (DailyMed, revised August 2026)
- The Ozempic ladder and 2 mg ceiling, checked for a semaglutide-to-tirzepatide conversion and carrying noneFDA prescribing information for Ozempic injection (DailyMed, revised June 2026)
- The Mounjaro ladder, checked for a conversion from semaglutide and carrying noneFDA prescribing information for Mounjaro (DailyMed, revised August 2026)
- The Saxenda ladder, checked for a dose conversion and carrying noneFDA prescribing information for Saxenda (DailyMed, revised February 2026)
- The Rybelsus ladder, checked for a dose conversion and carrying noneFDA prescribing information for Rybelsus and Ozempic tablets (DailyMed)
