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[GLP-1 · Switching]

Switching from semaglutide to tirzepatide: is there a conversion?

Label wording · Trial starting doses · Overlap

Short answer: No. Neither the Zepbound, Mounjaro, Wegovy nor Ozempic label gives a semaglutide-to-tirzepatide dose conversion, and no randomized trial has tested that switch.12 The closest trial, SURPASS-SWITCH, moved people from dulaglutide to tirzepatide and started everyone at 2.5 mg.3 Your prescriber decides the starting dose.

This page sticks to what the labels and published studies actually say. It does not offer a conversion chart, because no label or trial provides one. For the head-to-head efficacy data, see Semaglutide vs tirzepatide: what did the head-to-head trial show?.

What do the labels and trials say about switching?

Current US labels and published studies, checked October 2026.
Semaglutide (Wegovy, Ozempic)Tirzepatide (Zepbound, Mounjaro)
MechanismGLP-1 receptor agonistGIP and GLP-1 receptor agonist
Approval statusFDA approvedFDA approved
Label starting dose0.25 mg weekly for 4 weeks22.5 mg weekly for 4 weeks1
Label escalationStep up every 4 weeksUp by 2.5 mg, at least 4 weeks apart
Switching from another GLP-1 drugNot addressed (Wegovy covers only injection-to-tablet switching)2Not addressed14
Using both togetherWegovy: not recommended with any other GLP-1 receptor agonistZepbound: not recommended with any GLP-1 receptor agonist
Half-lifeabout 7 daysabout 5 days
Time to peak (Tmax)1 to 3 days5Median 24 hours (8 to 72)1
Dosing frequencyOnce weeklyOnce weekly
Pen / vial strengths0.25 to 2.4 mg pens, plus 7.2 mg (Wegovy HD)2.5 to 15 mg pens and vials
Missed-dose windowOzempic: 5 days. Wegovy: restart titration after 2 or more missed doses24 days (96 hours)1
Notable label warningsBoxed thyroid C-cell tumor warning; pancreatitis, gallbladder, kidney injuryBoxed thyroid C-cell tumor warning; pancreatitis, gallbladder, kidney injury

Reviewed . Half-life figures are shown only where the value Dose Track uses agrees with the cited source.

How did trials handle the starting dose?

  • SURPASS-SWITCH (282 adults with type 2 diabetes on dulaglutide, 40 weeks): tirzepatide started at 2.5 mg weekly and rose by 2.5 mg every 4 weeks, with no credit for the prior dulaglutide dose.6 HbA1c fell 1.44% vs 0.67% and weight 10.5 kg vs 3.6 kg compared with staying on dulaglutide.3
  • Semaglutide to tirzepatide: the only published data are a retrospective series of 15 patients, all of whom started tirzepatide at 2.5 mg,7 and a model-based simulation from Lilly.8 Neither is a randomized trial.
  • SURMOUNT-5 compared the two drugs but did not switch anyone; both arms started at the lowest dose.9

Does semaglutide overlap with the first tirzepatide doses?

Semaglutide has a half-life of about a week, so after the last shot it takes several weeks to clear. During that time some semaglutide is still active while tirzepatide is starting. This is one reason the labels' starting doses are low and stepped up slowly. Logging both in a tracker shows the estimated overlap on one chart.

What should I ask my prescriber?

  • What starting dose of tirzepatide, and when after my last semaglutide shot?
  • How fast should I step up, and what side effects should prompt a pause?
  • What should I do if I miss a dose during the changeover?
Semaglutide vs tirzepatide: what did the head-to-head trial show?SURMOUNT-5 results, label titration, half-life Retatrutide vs tirzepatide: how do they compare?Triple vs dual agonist, TRIUMPH results, status

Frequently asked questions

What dose of tirzepatide equals 1 mg of semaglutide?+
There is no official equivalent. No US label gives a conversion between semaglutide and tirzepatide, and no randomized trial has tested one. Your prescriber decides the starting dose.12
Do you have to restart at 2.5 mg when switching to tirzepatide?+
The label starting dose for tirzepatide is 2.5 mg, and the label does not address people coming from another GLP-1 drug. In the SURPASS-SWITCH trial (from dulaglutide) and a small semaglutide case series, everyone started at 2.5 mg.67
How long after my last semaglutide shot do I start tirzepatide?+
The labels do not say. Both are weekly drugs, and the Zepbound and Wegovy labels advise against using them together, so the timing is a question for your prescriber.
Can I track a switch in Dose Track?+
Yes. Log your last semaglutide shots and your first tirzepatide shots, and the app shows the estimated levels of both on one chart.

Sources

  1. Zepbound (tirzepatide) prescribing information. DailyMed, revised August 2026.
  2. Wegovy (semaglutide) injection and tablets prescribing information. DailyMed, revised June 2026.
  3. SURPASS-SWITCH: switching from dulaglutide to tirzepatide in type 2 diabetes. Ann Intern Med. 2025;178:609.
  4. Mounjaro (tirzepatide) prescribing information. DailyMed, revised August 2026.
  5. Ozempic (semaglutide) injection prescribing information. DailyMed, revised June 2026.
  6. SURPASS-SWITCH trial record (NCT05564039). ClinicalTrials.gov.
  7. Kurinami N, et al. Switching from semaglutide to tirzepatide: retrospective case series. 2025.
  8. Urva S, et al. Model-based simulation of switching from GLP-1 receptor agonists to tirzepatide. 2024.
  9. SURMOUNT-5 trial record and posted results (NCT05822830). ClinicalTrials.gov.

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