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Semaglutide to tirzepatide dose conversion

You are trying to work out how much to draw or when to step up.

Reference and calculator, not medical advice. Dosing figures below are transcribed from FDA-approved prescribing information and link back to it. Last reviewed August 2026.

There is no conversion. Not one that is hard to find, or that varies by clinic — no equivalence between semaglutide and tirzepatide doses appears in any of the prescribing information, because the two are different molecules acting on different receptor targets and no study established an exchange rate between them.

The strongest evidence that this absence is deliberate rather than an oversight is what the labels do contain. The Wegovy label gives switching instructions in detail — but only between its own two forms. Moving from the 25 mg tablet to the injection: discontinue the tablets, and the following day start 2.4 mg once weekly. The reverse direction is specified too. Same molecule, named doses, exact timing.

Manufacturers publish switching guidance when they have the data to support it. Between semaglutide and tirzepatide, none of them publishes anything — which tells you the equivalence has not been established, not that it is a trade secret.

Side-by-side

Structural facts from each product’s prescribing information.

ProductActive ingredientIndicationFrequencyStartMax labelledSteps to max
Zepbound
Eli Lilly		TirzepatideWeight managementWeekly2.5 mg15 mg6
Wegovy
Novo Nordisk		SemaglutideWeight managementWeekly0.25 mg2.4 mg5

What the labels do say about starting tirzepatide is unconditional. Zepbound begins at 2.5 mg once weekly for four weeks, for all indications, with no clause adjusting that for people arriving from another GLP-1. A switch restarts the schedule; it does not resume partway up it.

Zepbound titration schedule

Tirzepatide · once weekly · subcutaneous injection · as published in the prescribing information

StepDoseNotes
Weeks 1–42.5 mgStarting dose — not intended for weight loss effect
Weeks 5–85 mg—
Weeks 9–127.5 mg—
Weeks 13–1610 mg—
Weeks 17–2012.5 mg—
Week 21+15 mgMaximum dose

This is the labelled default. Holding at a step longer than shown is common practice and is a decision for your prescriber. Transcribed from the Zepbound prescribing information (label revised 6 May 2026); checked against that label on 7 August 2026.

One more instruction that matters if you are mid-switch: the Wegovy label states that concomitant use with any other GLP-1 receptor agonist is not recommended. These are not products to overlap or taper across.

Common questions

I found a conversion chart on another site. Is it wrong?
It is not sourced from any label, because no label contains one. Charts like that are typically built by matching milligram numbers or trial weight-loss percentages, neither of which establishes clinical equivalence between two different molecules. Ask where the numbers came from; there is no primary document to point at.
Why can I not just match the milligrams?
The two run on completely different scales — tirzepatide to 15 mg, semaglutide injection to 2.4 mg. A sixfold difference in the numbers reflects different molecules, not different strengths of the same thing. 5 mg of one is not comparable to 5 mg of the other in any direction.
So what actually happens when someone switches?
That is a prescriber decision and this page will not model it. What the labels support is that tirzepatide has one starting dose, 2.5 mg, and that the two products are not to be used together.
Does the same apply going the other way?
Yes. There is no tirzepatide-to-semaglutide conversion either, for the same reason, and Wegovy has its own starting dose of 0.25 mg with its own escalation.

Common questions

What is the starting dose of Zepbound?
The prescribing information lists 2.5 mg once weekly as the starting dose, held for the first four weeks before any increase.
What is the maximum labelled dose of Zepbound?
15 mg once weekly, reached through the stepped schedule shown above.
How many units is 5 mg at 20 mg/mL?
25.0 units on a U-100 syringe. The arithmetic is (dose ÷ concentration) × 100, and it only holds if the concentration on your vial matches.

Sources and last review

Every dosing figure on this page is transcribed from an FDA-approved label and links back to it. Conversions are arithmetic you can repeat by hand. Nothing here is reviewed by a clinician, and this site does not employ one — which is exactly why what I do publish stays traceable to its source.

Transcribed from the labels above and checked by me — Gavin, who builds this site, takes a GLP-1, and is not a clinician. Last reviewed August 2026. Found an error? [email protected] — I treat corrections as bugs. How this site is built and funded.

Citing this page

The figures here are transcribed from FDA-approved labels and each links to its source. If you are writing about this, quote the label rather than this site where you can — and if this page saved you the transcription, a link is appreciated.

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