Switching between GLP-1 drugs is common — insurance formulary changes, side-effect intolerance, an efficacy plateau, or hitting the top of the dose ladder all push patients from one agent to another. The FDA labels for Wegovy, Zepbound, Ozempic, Mounjaro, and Saxenda do not spell out head-to-head switching protocols. The matrix below stitches the label titration rules together with the clinical-experience patterns from trial extensions (STEP-8, SURMOUNT-5) and current endocrinology consensus so you have one reference card to talk through with your prescriber.
Switching matrix
| From | To | Recommended new starting dose | Wait time from last dose |
|---|---|---|---|
| Wegovy (semaglutide) | Zepbound (tirzepatide) | 2.5 mg weekly (lowest titration step) | 1 week (one full weekly dosing interval) |
| Zepbound (tirzepatide) | Wegovy (semaglutide) | 0.25 mg weekly (lowest titration step) | 1 week |
| Ozempic (semaglutide, T2D label) | Mounjaro (tirzepatide, T2D label) | 2.5 mg weekly | 1 week |
| Saxenda (liraglutide, daily) | Wegovy (semaglutide, weekly) | 0.25 mg weekly | 1 day (skip the next daily Saxenda; start Wegovy the same week) |
| Ozempic (semaglutide, T2D label) | Wegovy (semaglutide, obesity label) | Continue at the equivalent dose — same molecule, same dosing strengths up to 2.0 mg | 1 week (replace the next weekly dose) |
| Mounjaro (tirzepatide, T2D label) | Zepbound (tirzepatide, obesity label) | Continue at the equivalent dose — same molecule, same dosing strengths | 1 week (replace the next weekly dose) |
| Rybelsus (oral semaglutide) | Injectable semaglutide (Wegovy or Ozempic) | 0.25 mg weekly. PK is different — oral bioavailability is <1%, so the 14 mg oral dose is not equivalent to any injection strength. Re-titrate from the bottom. | 1 day after the last oral tablet |
Why restart titration when the drug class is the same?
Different GLP-1 drugs have different receptor selectivity profiles. Semaglutide and liraglutide are pure GLP-1 receptor agonists. Tirzepatide is a dual GIP/GLP-1 agonist, so the GI tolerability profile is not identical even at “equivalent” weight-loss potency. Receptor downregulation from one agonist does not produce cross-tolerance to another agonist’s peak side-effect profile. Patients on Wegovy 2.4 mg who feel no nausea can still get knocked over by Zepbound 7.5 mg or 10 mg if they skip the lower steps, because the gut has not seen tirzepatide-specific GIP-receptor activation before. The titration ladder exists to acclimate the gut, not to titrate up to a known therapeutic threshold.
Common switching scenarios
- Insurance forced a formulary change. Most common driver. PBMs move semaglutide and tirzepatide on and off preferred tiers each plan year.
- Inadequate response at the top dose. If Wegovy 2.4 mg has produced <5% weight loss at week 16, the label itself calls for reassessment; a switch to tirzepatide is a reasonable next step (SURMOUNT-5 showed superiority).
- Severe or persistent side effects. Refractory nausea or diarrhea on tirzepatide can sometimes improve on semaglutide because the GIP component drops out.
- Dose ladder ceiling reached. A patient at Wegovy 2.4 mg or Saxenda 3.0 mg who still has weight to lose has nowhere to go on the current drug.
- Formulary tier change mid-year. Even continuing the same molecule (Ozempic to Wegovy, Mounjaro to Zepbound) requires a new prescription and prior auth for the new label.
- Compounded-to-brand conversion. Patients moving off a compounded semaglutide or tirzepatide onto the FDA-approved brand should restart at the brand label’s lowest dose unless the prescriber has documented the exact compounded strength and titration history.
Red flags during a switch
- Severe nausea or vomiting in the first 1–2 weeks. If the new drug’s starting dose was set too high, the body has not had time to acclimate. Drop back to the lowest step and re-climb slowly.
- Hypoglycemia if on insulin or a sulfonylurea. Switching between GLP-1s while on a secretagogue requires the same dose-reduction caution as starting a GLP-1 fresh. Coordinate with the prescriber before the first new injection.
- Dose-stacking risk. Never overlap two GLP-1 drugs. If the new prescription arrives before the old supply is finished, do not bridge with both — pick one, follow the wait-time rule, then switch.
- Prior-auth delays leave a gap. If the gap stretches past 4 weeks, the labels say to reassess and re-titrate — do not restart at the prior maintenance dose. Send the prescriber a portal message rather than self-restarting.
- Severe, persistent abdominal pain at any point during the switch, especially radiating to the back. Possible acute pancreatitis; discontinue and seek same-day evaluation.
What this cheat sheet does not cover
This page is the outpatient switching framework for adults on GLP-1 receptor agonists for weight management or type 2 diabetes. It does not cover switching during pregnancy (all GLP-1s are contraindicated; see the pregnancy and fertility cheat sheet), perioperative management around the switch (see the sick-day guide for the ASA hold rules), pediatric switching (Saxenda and Wegovy both have pediatric labels but switching protocols are not standardized), or transitions from a GLP-1 to a non-GLP-1 weight-management drug (Qsymia, Contrave, naltrexone-bupropion). Those require condition-specific decision support that a generic switching matrix cannot provide.
Related on Weight Loss Rankings
- All cheat sheets — the full one-page reference library.
- Wegovy Dose Ladder Cheat Sheet — the weekly semaglutide titration schedule a switch onto Wegovy must follow.
- Zepbound Titration Schedule Cheat Sheet — the weekly tirzepatide ladder a switch onto Zepbound must follow.
- GLP-1 drug matchups index — head-to-head verdict pages for every paired switch in the matrix above.
Sources
- DailyMed. WEGOVY (semaglutide) injection prescribing information. SetID ee06186f-2aa3-4990-a760-757579d8f77b. Dosage and Administration: starting dose 0.25 mg weekly, escalate over 16+ weeks.
- DailyMed. ZEPBOUND (tirzepatide) injection prescribing information. SetID 487cd7e7-434c-4925-99fa-aa80b1cc776b. Dosage and Administration: starting dose 2.5 mg weekly, escalate every 4 weeks.
- DailyMed. OZEMPIC (semaglutide) injection prescribing information. SetID adec4fd2-6858-4c99-91d4-531f5f2a2d79. Same molecule and dosing strengths as Wegovy through 2.0 mg.
- DailyMed. MOUNJARO (tirzepatide) injection prescribing information. SetID d2d7da5d-ad07-4228-955f-cf7e355c8cc0. Same molecule and dosing strengths as Zepbound.
- DailyMed. SAXENDA (liraglutide) injection prescribing information. SetID 3946d389-0926-4f77-a708-0acb8153b143. Daily injection, half-life ~13 hours; 3-day re-titration rule for missed doses.
- DailyMed. RYBELSUS (semaglutide) tablets prescribing information. Oral bioavailability <1%; not dose-equivalent to injection on a mg basis.