Why there’s no conversion chart
If you’re switching from one GLP-1 to another, the honest answer to “what dose equals my current one?” is almost always that there isn’t one. No published dose-conversion chart exists between these drugs, with a single exception covered below. The tool above gives you the next best thing: whether your switch is between the same active drug or two different ones, and the standard dose you’d restart on.
The one switch the label does specify
There is exactly one pair with a written protocol, and it is between two forms of the same brand.
Wegovy’s label covers both the injection and the tablets, and it says how to move between them. Going from the 2.4 mg injection to 25 mg tablets, you wait one week after the last injection and then start the tablets once daily. Going from 25 mg tablets to the injection, you start 2.4 mg once weekly the day after the last tablet. If the 25 mg tablets were not tolerated, the label says to consider 1.7 mg injection instead.
The asymmetry is the part to notice. A week off in one direction, the next day in the other. It is not a mistake, and it is not a detail to average out.
This is genuinely the question the internet can’t answer well. Search “switching from Wegovy to Zepbound dosage chart” and you’ll find pages that either dodge the question or admit no chart exists. That’s not an oversight. It’s because semaglutide and tirzepatide are different molecules with different potencies, and no manufacturer or regulator has published an equivalence between them. Anyone who hands you a confident 1:1 conversion is making it up.
Same drug vs. different drug
The switch falls into one of two cases, and the tool tells you which:
- Same active drug (for example Ozempic → Wegovy, both semaglutide, or Mounjaro → Zepbound, both tirzepatide). Sharing a molecule does not make the doses interchangeable. These products are approved on different dose scales and in different devices, and one semaglutide label states outright that two of its products are not substitutable on a milligram-to-milligram basis. Your prescriber decides whether to step in higher or start from the bottom.
- Different drug (for example Wegovy → Zepbound, semaglutide → tirzepatide). There’s no equivalence to lean on. The standard approach is to restart at the new drug’s starting dose and titrate up, which has a hidden upside: it gives your body a fresh, gentle on-ramp and limits the side effects that come with a sudden jump.
How switching usually goes
The mechanics depend on why you’re switching:
- Switching for better results (you’ve plateaued, or want tirzepatide’s larger average loss): if you tolerate your current drug well, many clinicians start the new one promptly, often at its starting dose, and titrate as usual.
- Switching because of side effects: some clinicians add a short gap, a week or two, before starting the new drug, to let the old one clear.
Either way, restarting low rarely costs you much progress. The drug stays in your system as you ramp back up, appetite effects tend to persist, and most people reach an effective dose within a couple of months.
The bottom line
Use this tool to walk into your appointment informed: know whether you’re doing a same-molecule or cross-molecule switch, and what the usual restart dose is. But the actual plan, meaning restart dose, whether to wait, and how fast to climb, is a decision for your prescriber, made around your tolerance and your reason for switching. This is educational information, not a dosing instruction or medical advice.