No conversion chartMilligrams are not interchangeable
A medical transition—not a direct swap
Switching between Wegovy, Mounjaro and Ozempic
These medicines are not dose-equivalent. A safe transition depends on the indication, last injection, current dose, response, side effects, diabetes treatment and the reason for changing.
WegovySemaglutideDoctor review
MounjaroTirzepatideReview timingThe last dose and current symptoms matter
Indication firstOzempic is authorised for type 2 diabetes
Before changing medicine01 02 03 04 05 06
What the doctor reviews before choosing the next pathway
Why are you switching?
Side effects, inadequate response, stock availability, a new diagnosis or a change in clinical priorities can lead to different decisions.
What was the last treatment?
The exact product, strength, date of the last injection and total time on treatment must be confirmed. A packaging photo can prevent errors.
How well was it tolerated?
Ongoing nausea, vomiting, dehydration, abdominal pain or constipation may need assessment before another medicine is started.
Are diabetes medicines involved?
Insulin or medicines that can cause low blood glucose may require additional monitoring and adjustment by the clinician.
What is the authorised indication?
Wegovy and Mounjaro have weight-management indications. Ozempic is authorised for insufficiently controlled type 2 diabetes in the EU.
What starting dose is appropriate?
There is no simple conversion. The new dose is chosen from the new medicine’s schedule and the patient’s individual circumstances.
Wegovy
- Semaglutide, a GLP-1 receptor agonist
- Once-weekly weight-management treatment
- Previous dose does not translate directly to tirzepatide
No dose equivalenceThe plan must be prescribed
Mounjaro
- Tirzepatide, acting through GIP and GLP-1 receptors
- Once-weekly weight-management treatment
- Uses its own starting and escalation schedule
Confirm the last dose
Write down the medicine, strength and exact date of the last injection. Do not rely on memory or an online dose-conversion chart.
Complete the clinical review
The doctor reviews response, side effects, medical history, diabetes treatment and why the switch is being considered.
Receive a new prescribed plan
The clinician selects the new medicine, starting dose and timing. Do not overlap products or use leftover pens unless specifically instructed.
Monitor after the change
Track appetite, weight, glucose where relevant, gastrointestinal effects and hydration. Review tolerability before any increase.
!
Safety first
Never convert or overlap the medicines yourself
A milligram of semaglutide is not equivalent to a milligram of tirzepatide. Starting too high, overlapping injections or restarting after a gap without review can increase the risk of adverse effects.
Call 112 for a life-threatening emergency.
Common questions
Switching between treatments: questions
Can I switch immediately between Wegovy and Mounjaro?
There is no universal timing rule for every patient. The prescriber considers the last injection, current dose, side effects, diabetes medicines and the proposed starting dose.
Is 1 mg semaglutide equal to a Mounjaro dose?
No. Semaglutide and tirzepatide are different medicines and there is no validated milligram-for-milligram conversion.
Can I overlap Wegovy and Mounjaro?
Do not overlap the medicines unless a specialist has explicitly instructed you to do so. Combining them can increase adverse effects and is not a routine switching method.
Will I start the new medicine at its lowest dose?
The prescriber selects the starting dose individually. Previous treatment does not automatically justify beginning another product at a high dose.
Can I switch because my pharmacy has no stock?
Availability may be a reason to discuss alternatives, but the replacement still requires clinical review and a new prescription.
Can Ozempic replace Wegovy for weight loss?
Ozempic is authorised for type 2 diabetes in the EU and is not an automatic weight-management substitute for Wegovy.
What information should I provide before switching?
Provide the exact product, dose, date of the last injection, duration of treatment, weight trend, side effects, medical history and all diabetes medicines.
What if I had severe side effects on the previous treatment?
Tell the prescriber before taking another dose. The symptoms may need assessment and the new treatment may need to be delayed, started differently or avoided.
Clinical sources: EMA — Wegovy · EMA — Mounjaro · EMA — Ozempic. The official product information does not provide a milligram-for-milligram conversion between these medicines. An individual prescribing review is required.
Medically reviewed
Dr Ben Harry Clegg
General practitioner · Málaga registration 292911940 · Nerja Medical Center NICA 55712
Clinical review date: 9 August 2026
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