Weight Loss
Switching Between Wegovy and Mounjaro
In one sentence: You can switch between Wegovy and Mounjaro, but because they are different medicines with different doses, a switch has to be planned by a prescriber, who will usually start you on the lowest dose of the new medicine and build it up rather than matching your previous dose.
At a glance
Switching is possible, in either direction, but it must be decided and managed by a prescriber.
Doses are not matched one-for-one, because semaglutide and tirzepatide are different medicines.
You usually start low on the new medicine and titrate up, rather than jumping to an equivalent dose.
Switching to Mounjaro adds a contraception step for anyone on the pill; switching to Wegovy removes it.
Gut-related side effects may return for a while as you build up the new medicine.
Switch for suitability, not to chase results. Neither medicine is presented here as better.
People sometimes consider moving between Wegovy and Mounjaro, whether because of side effects, availability or a prescriber's advice. This guide explains whether you can switch, why people do, how a switch is usually handled, the dose and contraception points to know, and how to do it safely. If you are still comparing the two, start with Wegovy vs Mounjaro.
"Switching is common enough, but it is not something to do on your own by simply buying the other product. The two medicines are dosed on completely different scales, so a prescriber needs to set your new starting dose and plan the change. Done properly, it is straightforward, but the planning is what keeps it safe."
Key takeaways
Can you switch between Wegovy and Mounjaro?
Yes, in either direction, but only with a prescriber's guidance, because they are different medicines with different doses.
Do you match your previous dose?
No. You usually start the new medicine at its lowest dose and build up, rather than matching the dose you were on.
Is there a special safety point?
Yes. Switching to Mounjaro means using backup contraception if you take the pill, for a period after starting and after each dose rise.
Why do people switch?
Usually for tolerability, suitability, availability or cost, decided with a prescriber, not to chase a "better" result.
Can you switch between Wegovy and Mounjaro?
Yes, switching in either direction is possible, but it is a clinical decision, not a straight swap you should arrange yourself. Wegovy contains semaglutide and Mounjaro contains tirzepatide, so they are genuinely different medicines that happen to be used for the same goal. Because of that, a prescriber needs to plan the change, set your new dose and advise on timing. Any switch is still supplied only after a clinical assessment.
Why do people switch between Wegovy and Mounjaro?
There are several practical reasons a prescriber and patient might consider a switch, and they are about fit rather than one medicine being better than the other:
Tolerability: if side effects are difficult on one, the other may suit better.
Suitability: your wider health, other conditions and other medicines can make one a better fit.
Availability: supply of weight-management injections can vary, which sometimes prompts a change.
Cost: the ongoing cost of private treatment may be a factor.
Response and review: a prescriber may suggest a change as part of an ongoing review of how treatment is going.
How does switching work?
There is no single official protocol for switching between these two medicines, so the approach is individual and set by your prescriber. In practice, switching does not involve a long gap: because both are weekly injections, the new medicine is usually started in place of the next scheduled dose, at the new medicine's own starting dose. You do not double up, and you do not carry your old dose across. Your prescriber will confirm the exact timing and dose for you.
What dose do you start on when switching?
You start on the lowest dose of the new medicine and build up, because the two are dosed on different scales and are not equivalent milligram-for-milligram. Wegovy starts at 0.25 mg once weekly and steps up to a 2.4 mg maintenance dose,1 while Mounjaro starts at 2.5 mg once weekly and steps up towards a maximum of 15 mg.2 Starting low again helps manage the side effects that can come with a new medicine, even if you were on a high dose of the previous one.
Switching to Mounjaro: the contraception point
If you use the contraceptive pill, there is an important difference to plan for when switching to Mounjaro. The Mounjaro Summary of Product Characteristics advises "switching to a non-oral contraceptive method, or add a barrier method of contraception upon initiating tirzepatide therapy (for 4 weeks), or after each dose escalation (for 4 weeks)".2 Wegovy does not carry this advice, so switching the other way, to Wegovy, removes that step.1
Important: If you take the pill and switch to Mounjaro, use extra or non-oral contraception for four weeks when you start and after each dose increase. Raise this in your consultation so it is planned in.
What side effects might you notice when switching?
Because you build the new medicine up from a low dose, you may notice gut-related side effects again for a while, such as nausea, even if you had settled on your previous treatment. This usually eases as your body adjusts, in the same way it did the first time. Our guide to Wegovy side effects covers how to manage these, and the same general tips apply while titrating either medicine.
How to switch safely
Talk to your prescriber first. Do not simply buy the other product and swap.
Agree on your new starting dose and timing, which will be the new medicine's low starting dose, not your old dose.
Do not overlap or double up. Stop the old medicine as directed and start the new one as planned.
Sort out contraception if switching to Mounjaro, using backup for the advised periods if you take the pill.
Follow the new titration schedule and report any difficult side effects so your plan can be adjusted.
If you are moving onto Wegovy, you can begin the process through an online weight-management consultation, or read about the Mounjaro (tirzepatide) option.
"The mistake I want people to avoid is carrying their dose across. If you were on a high dose of one, you do not start high on the other. You go back to the new medicine's starting dose and build up again. It feels like a step back, but it is what keeps side effects manageable and the switch safe."
Frequently asked questions
Can you switch straight from Wegovy to Mounjaro?
You can switch, but not by matching your dose. A prescriber will usually start you on Mounjaro's lowest dose of 2.5 mg and build up, regardless of the Wegovy dose you were on. The switch should be planned with a prescriber, who will confirm the timing.
Do you need a gap between Wegovy and Mounjaro?
Because both are weekly injections, a long gap is not usually needed. The new medicine is generally started in place of the next scheduled weekly dose, at its own starting dose. Your prescriber will confirm the exact timing for your situation.
What dose of Mounjaro do you start on after Wegovy?
You start on Mounjaro's lowest dose, 2.5 mg once weekly, and step up over time, rather than matching your previous Wegovy dose. Starting low again helps manage side effects, even if you were on a high dose before.
Do you need extra contraception when switching to Mounjaro?
If you take the contraceptive pill, yes. Mounjaro can reduce the pill's effectiveness, so backup or non-oral contraception is advised for four weeks when you start and after each dose increase. Switching to Wegovy does not carry this advice.
Will side effects come back if you switch?
They can, for a while. Because you build the new medicine up from a low dose, you may notice gut-related effects such as nausea again as your body adjusts. This usually eases with time, just as it did when you first started treatment.
Should you switch because one is more effective?
Neither medicine is presented here as better than the other. Switching is usually about tolerability, suitability, availability or cost, decided with a prescriber. If you are considering a change, discuss your reasons so the right decision can be made for you.
Related Wegovy guides
Sources and references
Wegovy FlexTouch Summary of Product Characteristics (SmPC), emc. Semaglutide dose range 0.25 to 2.4 mg once weekly, and that it does not reduce the effectiveness of oral contraceptives.
Mounjaro Summary of Product Characteristics (SmPC), emc. Tirzepatide dose range 2.5 to 15 mg once weekly, and the oral contraceptive advice (barrier or non-oral method for 4 weeks at initiation and after each dose escalation).
Medical disclaimer: This article is for general information and does not replace advice from a qualified healthcare professional. Wegovy and Mounjaro are prescription-only medicines. Do not switch treatments without advice from a prescriber. Always read the patient information leaflet and speak to your clinician or pharmacist about your individual circumstances.
Our commitment to accuracy: This page was written using the electronic medicines compendium (emc), and is reviewed by our Superintendent Pharmacist. We review our weight-management content regularly and update it as guidance changes.
About the author
Blog author
Dayna Sheppard
Dayna is a pharmacy manager with over 15 years of pharmacy experience. She is focused on delivering a safe and excellent pharmacy service for patients.
Medically reviewed by
Medical reviewer
Taslima Hussain
Taslima is a pharmacist who is passionate about patient care. She has experience working in community pharmacy as a locum.
