# How long does a pen last?

> Usually 4 weeks. A Mounjaro KwikPen, a Wegovy FlexTouch and a Zepbound KwikPen each hold 4 doses, and US single-dose Zepbound pens come 4 to a box, so your fifth weekly jab needs a new pen. Wegovy 7.2mg is the exception: three 2.4mg injections a dose. How long a started pen keeps differs by brand.

Canonical: https://jabwise.app/guides/how-long-a-pen-lasts. Sources checked 12 October 2026. General information, not medical advice: follow your prescriber.

## Work out your dates

Pick your pen and its first dose day for the four dose days, when the next is due and the label’s limit. It counts dates; it doesn’t change your prescriber’s advice.


## How long a pen keeps

Each label’s own limit, quoted as written.

- **Mounjaro KwikPen**: In the box: One pen, four doses; The label’s limit: "can be stored unrefrigerated not above 30 ºC for up to 30 days after first use and then the pen must be discarded" ([Mounjaro KwikPen patient leaflet](https://www.medicines.org.uk/emc/product/15481/pil))
- **Wegovy FlexTouch**: In the box: One pen, four doses; at 7.2mg, three make one dose; The label’s limit: "You can keep the pen for 6 weeks when stored at a temperature below 30°C or in a refrigerator (2°C to 8°C)" ([Wegovy FlexTouch patient leaflet](https://www.medicines.org.uk/emc/product/13800/pil))
- **Zepbound KwikPen**: In the box: One pen, four doses; The label’s limit: "after a total of 30 days at room temperature, 30 days after first use, or after taking 4 weekly doses" ([Zepbound prescribing information](https://uspl.lilly.com/zepbound/zepbound.html))
- **Zepbound single-dose pens**: In the box: Four pens, one dose each; The label’s limit: "can be stored unrefrigerated at temperatures not to exceed 30°C (86°F) for up to a total of 21 days" ([Zepbound prescribing information](https://uspl.lilly.com/zepbound/zepbound.html))

## Before the first dose, and after the last

- **Before you start**: Fridge, 2 to 8°C, say Mounjaro, Wegovy and Ozempic; Zepbound’s label also allows limited room temperature.
- **If it froze**: The Mounjaro, Wegovy and Ozempic leaflets are all clear that a pen that has been frozen must not be used.
- **After dose 4**: There may be a little medicine left in your pen after dose 4. Mounjaro’s leaflet says not to try to use it.

## Questions

### How many doses are in a Mounjaro pen?

Four. The UK leaflet says each KwikPen contains 4 doses, in whichever strength you’re prescribed. Taken once a week, that’s 4 weeks.

### How long does a Wegovy pen last once it’s open?

The Wegovy FlexTouch leaflet says you can keep the pen for 6 weeks when stored below 30°C, or in the fridge. It holds four doses, so on a weekly schedule you’ll finish it well inside that.

### Does a Wegovy pen last 4 weeks at 7.2mg?

No. The leaflet gives the 7.2mg dose as three 2.4mg injections on the same day, says you may need to use multiple pens, and asks you to make sure you have enough to complete the dose before you start. Your pharmacist can help you plan supply.

### Is there medicine left after the last dose?

There can be. Mounjaro’s leaflet says not to try to use any remaining medicine, and that the pen must be properly discarded after the last dose.

### What if my pen has been frozen?

The Mounjaro, Wegovy and Ozempic leaflets all say not to use a pen that has been frozen. Your pharmacist can tell you what to do next.

## In Jabwise: Supply

Jabwise tells you when to reorder. Set when your next order is due and how often it repeats, then choose when you’d like the nudge: on the day, or up to 14 days before. The reminder never names your medicine on the Lock Screen.

## Getting real advice

- **A pharmacist, your doctor or NHS 111**: If you’re not sure how to use your medicine, or a side effect bothers you or won’t go away. NHS 111 if you think you might be having serious side effects, or you’ve used too much. [NHS: Semaglutide](https://www.nhs.uk/medicines/semaglutide/), [NHS: Tirzepatide](https://www.nhs.uk/medicines/tirzepatide/), [NHS 111 online](https://111.nhs.uk/)
- **Report a side effect**: Anyone can, not only doctors. [Yellow Card (UK)](https://yellowcard.mhra.gov.uk/), [MedWatch (US)](https://www.fda.gov/safety/medwatch-fda-safety-information-and-adverse-event-reporting-program)

## Sources

- [Mounjaro KwikPen patient leaflet](https://www.medicines.org.uk/emc/product/15481/pil)
- [Wegovy FlexTouch patient leaflet](https://www.medicines.org.uk/emc/product/13800/pil)
- [Zepbound prescribing information](https://uspl.lilly.com/zepbound/zepbound.html)
- [Ozempic patient leaflet](https://www.medicines.org.uk/emc/product/9748/pil)