There is no established dose conversion between semaglutide and tirzepatide, and any chart claiming otherwise is inventing one. They are different molecules acting on different receptor combinations, studied on their own titration schedules. Switching means starting where your prescriber decides and titrating up, not translating your current dose into an equivalent.
Do not use a conversion chart from a website, a forum or a seller. These circulate widely and they are not derived from comparative trials, because those trials do not exist for this purpose. Working out your own starting dose is how people begin considerably higher than they should.
For how this fits into the wider titration picture, see GLP-1 Dosing and Titration: The Complete Guide.
Why no conversion exists
A dose equivalence requires head-to-head study designed to establish it. These molecules were developed and trialled separately, on separate schedules, against separate endpoints.
They also act differently. Semaglutide engages the GLP-1 receptor; tirzepatide engages GLP-1 and GIP receptors. Two drugs producing broadly similar effects through different mechanisms do not have a milligram-for-milligram relationship.
Tirzepatide vs. Semaglutide: Efficacy Data Compared
What actually happens when you switch
Your prescriber selects a starting dose for the new drug, informed by your response and tolerance on the old one but not calculated from it.
You then titrate on the new product’s schedule. Expect the familiar pattern: symptoms flaring after each step and easing with time at that dose.
Where you start is usually lower than people expect, and that is deliberate. Tolerance to one molecule does not transfer cleanly to another.
Slow Titration: When and Why to Extend a Dose Managing Side Effects During Dose Escalation
Timing between the two
Do not overlap them. Your prescriber will advise on the gap between your last dose of one and the first dose of the other, and that guidance depends on how long each persists in your system.
If a switch leaves you holding supply of both, ask your pharmacist rather than using up the surplus.
Sort the coverage before the clinical part
This is where switches actually fail.
Your prior authorization does not transfer. The new product needs its own, under its own criteria, and approval for one says nothing about the other.
Check the new product on your formulary, note whether prior authorization or step therapy applies, and have the request filed before your current supply runs out.
GLP-1 Prior Authorization: What Your Doctor Actually Has to Submit What Is Step Therapy and How to Get an Exception Why Your Pharmacy Says Not Covered When Your Plan Says It Is
Before you switch at all
If the reason is tolerability, ask whether holding at your current dose or stepping back down has been tried. That resolves a good share of problems without a new titration and a new authorization.
If the reason is a plateau, check the ordinary explanations first, since switching does not address intake drift or a smaller body needing less.
If the reason is coverage or supply, that is a legitimate reason and worth naming plainly to your prescriber, since it affects what they arrange.
Can You Stay on a Lower Dose Long-Term GLP-1 Weight Loss Plateau: Causes and Fixes Switching Drugs Because of Shortage
What to tell your prescriber
The dose you reached, how long you were on it, how you tolerated it, and what your weight did. That is the information they actually use.
Also mention anything that made you stop tolerating it, since that may influence how cautiously they start you on the new one.
Before switching for tolerability, ask whether slowing down or staying at a lower dose has been tried, since either resolves most problems without a new titration. The coverage side is the part that stalls switches, covered in what a new prior authorization needs.
Frequently asked questions
What dose of tirzepatide equals my semaglutide dose?
There is no established equivalence. Your prescriber decides a starting dose rather than converting.
Why do conversion charts exist online?
People infer them from maximum doses or from anecdote. They are not derived from comparative trials.
Will I lose progress restarting lower?
Usually little. Working back up through tolerated doses is generally quicker than the first climb.
Do I need a new prior authorization?
Yes, under the new product’s criteria. Start it early.
Can I take both during the transition?
No. Ask your prescriber about the gap between them.
Will side effects be the same?
Broadly similar profile, and your individual tolerance may differ between the two.