Switching from Wegovy to Mounjaro: What to Know

If you're currently taking Wegovy and considering switching to Mounjaro when it becomes available in New Zealand, this guide covers what you need to know about making the transition safely and effectively.

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Why Consider Switching?

There are several reasons you might consider transitioning from Wegovy to Mounjaro:

• Greater weight loss potential: Clinical trials show Mounjaro produces approximately 50% more weight loss than Wegovy on average
• Plateau on current treatment: If your weight loss has stalled on Wegovy, Mounjaro's dual mechanism may help restart progress
• Not reaching your goals: If you haven't achieved the results you wanted with Wegovy
• Side effect profile: Some patients may tolerate one medication better than the other

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How the Medications Compare

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The Switching Process

There's no standardised protocol for switching between these medications, but here's what current evidence and clinical practice suggest:

Option 1: Direct Switch

Some clinicians recommend switching directly without a washout period:

• Take your last Wegovy dose as scheduled
• Start Mounjaro one week later on your usual injection day
• Begin at the recommended starting dose (2.5mg)

Option 2: Brief Washout

Others prefer a short washout period:

• Stop Wegovy after your last scheduled dose
• Wait 1-2 weeks before starting Mounjaro
• Begin at the recommended starting dose (2.5mg)

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Important: Starting Dose Considerations

Even if you're on the maximum dose of Wegovy (2.4mg), you'll likely need to start Mounjaro at or near the beginning of its titration schedule. This is because:

• Tirzepatide is a different molecule with different receptor activity
• Your body needs to adjust to the dual GLP-1/GIP mechanism
• Starting too high risks increased side effects

Your prescriber may recommend starting at 2.5mg or possibly 5mg depending on your tolerance and response to Wegovy.

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What to Expect When Switching

Side Effects

You may experience gastrointestinal side effects again when starting Mounjaro, even if you tolerated Wegovy well. The dual mechanism means your body needs to adjust to the additional GIP activity.

Weight Changes

During the transition and early titration phase:

• You may experience temporary weight stabilisation or slight regain
• This is normal and typically reverses once you reach therapeutic doses
• Long-term results are usually better than with Wegovy alone

Appetite

You may notice appetite returning somewhat during the transition. This usually improves as you titrate up on Mounjaro.

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When NOT to Switch

Switching may not be appropriate if:

• You're achieving excellent results with Wegovy and meeting your goals
• You have contraindications specific to tirzepatide
• You're pregnant, planning pregnancy, or breastfeeding
• You experienced severe side effects with GLP-1 medications

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Discuss with Your Doctor

Any switch between medications should be done under medical supervision. Your doctor will consider:

• Your current results and goals
• Your tolerance of Wegovy
• Any health conditions that might affect the switch
• The optimal timing and dosing approach

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Planning Ahead

If you're interested in switching to Mounjaro, we recommend:

• Continuing your current Wegovy treatment in the meantime
• Discussing your interest with your prescriber

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Support for Your Transition

At Well Revolution, we support people who wish to transition from Wegovy to Mounjaro. Our care team can help you plan the switch, monitor your progress, and adjust your treatment as needed.

We offer a free initial consultation to determine if Mounjaro is safe and appropriate for you.

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References

• Medsafe - Mounjaro Data Sheet
• Medsafe - Wegovy Data Sheet