What the labels contain
- Ozempic® injection: no section on switching to another GLP-1 medicine [1]. The only switching text for Ozempic® sits in the tablet label, about moving from the injection to Rybelsus® or Ozempic® tablets [2].
- Mounjaro®: no section on switching from another medicine. Its starting dose and steps (section 2.1) are written for anyone starting Mounjaro® [3].
- For anyone on the pill, the US Mounjaro® label covers the first four weeks and the four weeks after every step up: use a contraceptive that is not swallowed, or a barrier such as a condom on top [3].
Why there is no dose conversion
The two medicines have different active ingredients, and each label lists its own starting dose and steps for people starting it. No label turns a dose of one into a dose of the other, so a conversion table found elsewhere is not something the labels support. Where to start on the new medicine is set by your prescriber.
Side by side, from the labels
| Label item | Ozempic® (injection) | Mounjaro® |
|---|---|---|
| Active ingredient | Semaglutide, a GLP-1 receptor agonist | Tirzepatide, a GIP and GLP-1 receptor agonist |
| Maker | Novo Nordisk | Eli Lilly and Company |
| FDA-approved uses | Adults with type 2 diabetes: blood sugar control alongside diet and exercise; lowering the risk of major cardiovascular events in those with established cardiovascular disease; lowering the risk of kidney decline, kidney failure and cardiovascular death in those with chronic kidney disease. [1] | Blood sugar control in adults and children 10 and older with type 2 diabetes, alongside diet and exercise; lowering the risk of major cardiovascular events in adults with type 2 diabetes who are at high risk. [3] |
| How it is taken | Once a week, under the skin of the abdomen, thigh or upper arm, on the same day each week. | Once a week, under the skin of the abdomen or thigh, or the back of the upper arm, at any time of day. |
| Forms in the US | Multi-dose pens and single-dose prefilled syringes, in several strengths (section 3). | Single-dose pens, single-dose vials, multi-dose vials and the KwikPen® (four doses per pen) (section 3). |
| Dose steps | Section 2.2 of the label: a low starting dose, raised in steps. Not repeated here; your prescriber sets your steps. [1] | Section 2.1 of the label: a low starting dose, raised in steps of at least 4 weeks if more blood sugar control is needed. Not repeated here; your prescriber sets your steps. [3] |
| Half-life (section 12.3) | About 1 week [1] | About 5 days [3] |
| Most common side effects (label) | Nausea, vomiting, diarrhea, abdominal pain, constipation. | Nausea, diarrhea, decreased appetite, vomiting, constipation, indigestion, abdominal pain. |
| Storage (label) | Refrigerated (2–8 °C) before first use. After first use a pen can be kept for up to 56 days at 15–30 °C or in the fridge. Not to be frozen. | Refrigerated (2–8 °C). Single-dose pens and vials may be kept unrefrigerated up to 30 °C for a total of 21 days. Multi-dose vials and KwikPens® are discarded 30 days after first use or after 4 doses. |
| Boxed warning | Yes: risk of thyroid C-cell tumors. | Yes: risk of thyroid C-cell tumors. |
| In the EU (EMA) | Authorised since 2018 for adults with type 2 diabetes that is not controlled well enough. [5] | Authorised since 2022 for type 2 diabetes (age 10 and older) and for weight management in adults. Zepbound® is not a separate EU product. [4] |
Timing facts from the labels
| Label item | Ozempic® (injection) | Mounjaro® |
|---|---|---|
| Half-life (section 12.3) | About 1 week [1] | About 5 days [3] |
| Time to peak level (section 12.3) | 1 to 3 days after a dose [1] | 8 to 72 hours after a dose [3] |
| Steady state (section 12.3) | After 4 to 5 weeks of weekly doses [1] | After 4 weeks of weekly doses [3] |
| After the last dose (section 12.3) | About 5 weeks in the circulation after the last dose [1] | Not stated in the label [3] |
| Missed dose (section 2) | Taken within 5 days of the missed dose (section 2.1) [1] | Taken within 4 days (96 hours); after that, skipped (section 2.1) [3] |
| Section on switching | None in the injection label [1] | None [3] |
Switching the other way
Moving from Mounjaro® to Ozempic® is not covered by either label either [3][1]. The Ozempic® label’s starting dose and steps (section 2.2) are written for anyone starting Ozempic®; your prescriber decides where a person coming from tirzepatide begins.
Questions to bring to your prescriber
- When should the last Ozempic® dose be, and when the first Mounjaro® dose?
- Where on the Mounjaro® steps will I start, and when is the next step reviewed?
- Do any of my other medicines, including birth-control pills, need a change while I start [3]?
- Which side effects should I report, and how quickly?
Ozempic®, Wegovy®, Rybelsus®, Saxenda®, Victoza® and FlexTouch® are registered trademarks of Novo Nordisk A/S. Mounjaro®, Zepbound® and KwikPen® are registered trademarks owned or licensed by Eli Lilly and Company; Foundayo™ is a trademark of Eli Lilly and Company. PepLabo is not affiliated with or endorsed by these companies.
