People move between these drugs constantly, and for good reasons: an insurer reshuffles its preferred list, side effects prove intolerable, progress stalls, or someone reaches the top of a ladder with weight still to lose.
No label covers it. The manufacturers tested their drugs against placebo, not against each other's discontinuation. What follows stitches the titration rules together with what endocrinologists actually do — a card to talk through with your prescriber rather than a protocol to run yourself.
Where to start, and how long to wait
| Moving from | To | Start at | Gap |
|---|---|---|---|
| Wegovy | Zepbound | 2.5 mg — the very bottom | One week |
| Zepbound | Wegovy | 0.25 mg — the very bottom | One week |
| Ozempic | Mounjaro | 2.5 mg | One week |
| Saxenda (daily) | Wegovy (weekly) | 0.25 mg | A day — skip the next daily dose and start that week |
| Rybelsus (oral) | Injectable semaglutide | 0.25 mg. The oral and injected doses are not comparable in milligrams, so there is nothing to convert. | A day after the last tablet |
| Ozempic | Wegovy | Carry your dose across — same molecule, same strengths | Replace the next weekly dose |
| Mounjaro | Zepbound | Carry your dose across — same molecule, same strengths | Replace the next weekly dose |
The last two rows are the exception that proves the rule. Those pairs are the same drug wearing a different label, so nothing about your body changes — only the paperwork, which still means a fresh prescription and usually a fresh prior authorization.
Why you restart when it is the same class
This is the part worth understanding, because it is the instruction people are most tempted to skip after a year of doing fine.
Semaglutide and liraglutide act on the GLP-1 receptor. Tirzepatide acts on two — GLP-1 and GIP. Your gut may be thoroughly used to one of those and completely unacquainted with the other.
⛔ So someone sailing along on Wegovy at 2.4 mg with no nausea whatsoever can be floored by Zepbound at 7.5 mg, because nothing in their experience so far involved GIP. The ladder is not there to walk you up to a known threshold. It is there to introduce your digestive system to a molecule it has not met.
Why people switch
- The formulary moved. Easily the commonest reason, and nothing to do with your clinical situation.
- Not enough response at the top. Wegovy's own label calls for reassessment if 16 weeks at the target dose has not produced meaningful loss. Tirzepatide is a reasonable next move, and beat semaglutide when the two were compared directly.
- Side effects that will not settle. Sometimes worth going the other way — dropping from tirzepatide to semaglutide removes the GIP component altogether.
- You have run out of ladder. Sitting at the top of Wegovy or Saxenda with more to lose, there is nowhere left to climb on that drug.
- Coming off a compounded product onto the brand. Start at the brand's lowest dose unless your prescriber has the exact compounded strength and history documented — and frequently nobody does.
What to watch during a switch
- Bad nausea in the first fortnight usually means the new starting dose was set too high. Drop to the bottom and climb slowly rather than pushing through.
- Hypoglycemia if you take insulin or a sulfonylurea. A switch deserves the same caution as a first start. Sort those doses out before the first new injection, not after.
- ⛔ Never overlap two GLP-1s. If the new prescription lands before the old supply runs out, pick one. Do not bridge with both.
- A prior-authorization delay of more than four weeks is no longer a switch, it is a restart — do not resume at your old maintenance dose. Message your prescriber instead of deciding at home.
- Severe abdominal pain at any stage, especially reaching to the back. Stop and get seen the same day.
What this does not cover
Adults switching between GLP-1s for weight or type 2 diabetes. Not switching during pregnancy, where all of these should stop; not the surgery timing, which has its own page; not switching in children, where no standard exists; and not moving to a non-GLP-1 weight drug, which is a different decision altogether.
Where to go next
- Wegovy dose ladder — the schedule to follow when switching onto it.
- Zepbound ladder — likewise.
- Wegovy against Zepbound — what the evidence says about which way to switch.
- Brand names against molecules — why two of the rows above need no re-titration at all.