What is the equivalent dose of Wegovy (semaglutide) for a patient switching from 10 mg weekly of Mounjaro (tirzepatide)?

Switching from Mounjaro 10 mg to Wegovy: Dosing Strategy

There is no established dose equivalency between Mounjaro (tirzepatide) and Wegovy (semaglutide), and you should restart Wegovy at the standard initial dose of 0.25 mg weekly with gradual titration, even though the patient is on Mounjaro 10 mg. 1, 2

Why No Direct Dose Conversion Exists

• Tirzepatide and semaglutide have fundamentally different mechanisms of action - tirzepatide is a dual GIP/GLP-1 receptor agonist while semaglutide is a selective GLP-1 receptor agonist only, making direct dose equivalency impossible 3, 1

• Despite prior tolerance to one GLP-1 medication, the dual mechanism of tirzepatide means patients may experience new or different gastrointestinal side effects when switching between these agents 1

• Tirzepatide may delay gastric emptying differently than semaglutide, which could affect medication absorption and tolerability 1

Recommended Transition Protocol

Start Wegovy at the time of the next scheduled Mounjaro dose with no washout period required, given both medications have once-weekly dosing schedules 1

Standard Wegovy Titration Schedule

• Begin at 0.25 mg subcutaneously once weekly for 4 weeks 2
• Increase to 0.5 mg once weekly for 4 weeks 2
• Increase to 1.0 mg once weekly for 4 weeks 2
• Increase to 1.7 mg once weekly for 4 weeks 2
• Reach maintenance dose of 2.4 mg once weekly 2

Rationale for Full Titration

• Gradual dose titration is essential to minimize gastrointestinal adverse effects (nausea, vomiting, diarrhea, esophageal reflux), which remain common despite prior GLP-1 receptor agonist use 3, 1, 2

• The American Gastroenterological Association specifically recommends gradual titration even in patients with a history of semaglutide or other GLP-1 RA treatment 1

• Some patients may achieve significant clinical response at submaximal doses (such as 1.0 mg or 1.7 mg) and could continue at that dose long-term rather than escalating to 2.4 mg 2

Comparative Efficacy Context

• Tirzepatide 10 mg demonstrates superior weight loss compared to semaglutide 2.4 mg - in clinical trials, tirzepatide 10 mg achieved 12.8% weight loss versus 9.6% with semaglutide 2.4 mg 3

• Real-world data shows mean weight loss of -17.2 kg with tirzepatide versus -14.6 kg with semaglutide 2.4 mg after 1 year 4

• Patients should be counseled that they may experience less weight loss efficacy with Wegovy compared to their current Mounjaro regimen 5, 6

Monitoring and Safety Considerations

• Assess efficacy and safety at least monthly for the first 3 months and at least quarterly thereafter 3

• Monitor for gastrointestinal disorders including severe constipation and small-bowel obstruction/ileus progression 3

• Watch for potential cholelithiasis and gallstone-related complications 3

• Both medications carry a black box warning regarding thyroid C-cell tumors; do not use in individuals with personal or family history of medullary thyroid cancer or multiple endocrine neoplasia type 2 3, 1

• Use caution in patients with kidney disease when initiating or increasing dose due to potential risk of acute kidney injury 1

Practical Administration

• Wegovy can be administered at any time of day, with or without meals 2

• If a dose is missed and less than 5 days have passed, administer as soon as possible; if more than 5 days have passed, skip the missed dose 2

• If 2 consecutive doses are missed, consider resuming at the same dose if previously well-tolerated, or lowering the dose 2

• If 3 or more consecutive doses are missed, consider restarting the full titration schedule 2

Critical Pitfall to Avoid

Do not attempt to start Wegovy at a "higher" dose (such as 1.7 mg or 2.4 mg) based on the patient's current Mounjaro dose - this significantly increases the risk of severe gastrointestinal adverse events and treatment discontinuation, even though the patient has been tolerating Mounjaro 10 mg 1, 2