How to switch between GLP‑1 medications safely

Introduction

Switching between semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound) requires a plan from your prescriber. Your previous dose, side effects, other medicines, and treatment goals affect that plan. The labels do not provide a milligram-for-milligram conversion between semaglutide and tirzepatide. [3] [4] [5] [6]

Reasons to discuss a switch

Your clinician may consider another medication if you have troublesome side effects, have not met treatment goals, or cannot afford or obtain your prescription. Insurance coverage, formulary changes, and personal preference can also affect the decision. A switch does not guarantee better results or fewer side effects. [1]

In SURMOUNT-5, researchers compared weekly tirzepatide at the maximum tolerated dose of 10 or 15 mg with weekly semaglutide at 1.7 or 2.4 mg. At 72 weeks, adults with obesity but without diabetes lost an estimated mean 20.2% of body weight on tirzepatide and 13.7% on semaglutide. The trial did not test a switching schedule or semaglutide 7.2 mg, so those results cannot tell you which dose to start after a switch. [2]

Get the start date and dose in writing

Ask your prescriber to specify your last dose of the old medicine, first dose of the new medicine, starting strength, and escalation schedule. Bring your medication list and tell them about recent nausea, vomiting, or missed doses. A 2021 expert consensus on injectable GLP‑1 medicines recommends tailoring the transition to your prior treatment and how well you tolerated it. [1]

Wegovy and Zepbound labeling advises against use with another GLP‑1 receptor agonist or another product containing the same active ingredient. Do not add the new medicine to your existing regimen. Confirm unclear instructions with your prescriber before taking a dose. [4] [6]

Switching between semaglutide and tirzepatide

The U.S. Mounjaro and Zepbound labels start tirzepatide at 2.5 mg once a week. The Zepbound label specifies four weeks at 2.5 mg, followed by 5 mg once a week; 2.5 mg is not an approved maintenance dose. For later Zepbound increases, your prescriber follows the label’s 2.5 mg steps after at least four weeks on the current dose, considering your response and side effects. Mounjaro labeling allows 2.5 mg increases after at least four weeks on the current dose if you need more blood sugar control. Neither label gives an equivalent tirzepatide dose for a previous semaglutide dose. [5] [6]

The labeled initiation schedules for Ozempic and Wegovy injections start at 0.25 mg once a week for four weeks. Their later doses and approved uses differ. Your previous tirzepatide dose does not tell you which semaglutide dose to start, so ask your prescriber for the schedule for your exact product. [3] [4]

Your clinician may also need to adjust insulin or a sulfonylurea to reduce the risk of low blood sugar. Ask how often to check glucose during the transition. If you use an oral hormonal contraceptive and start tirzepatide, its labels advise a non-oral method or an added barrier method for four weeks after starting and four weeks after each dose increase. [5] [6]

Oral products have their own instructions

The Wegovy label gives specific directions for switching between certain Wegovy injection and tablet doses. Those directions do not provide a conversion to a different active ingredient. Ask your prescriber whether they apply to your current dose. [4]

Food instructions also differ. Take Wegovy tablets in the morning on an empty stomach with no more than 4 ounces of water, then wait at least 30 minutes before food, other drinks, or oral medicines. Foundayo (orforglipron) is a daily tablet that you can take with or without food. Follow the instructions for the tablet on your prescription. [4] [7]

Keep records and know when to call

For follow-up, note dose dates, symptoms, and weight changes. Add glucose readings if your care team asks you to monitor them. Agree on a review date and the treatment goals you will use to assess the new medicine. [1]

Contact your clinician if nausea, vomiting, or diarrhea persists. These symptoms can cause dehydration and kidney problems. Stop taking the medicine and seek medical care for severe abdominal pain that does not go away, with or without vomiting, because it can signal pancreatitis. Follow the warning instructions for your prescribed product. [3] [5]

Keep your medication history with Shotsy

Use Shotsy to log doses, side effects, and weight before and after a switch. You can share a PDF summary with your prescriber. Your record can support that conversation; your clinician chooses the dose and start date.

Conclusion

Confirm the last dose, first dose, and follow-up plan with your prescriber before changing medicines. Use the current instructions for the exact product you receive, and report symptoms that need care rather than waiting for your next appointment.

For related reading, see the medication comparison guide and first-month guide.