The weekly rule in each label
The five weekly injections share the basic rhythm but not every detail. The table keeps the wording of each label and the section where it appears; the rules for a missed dose and for moving the weekday have their own articles.
| Medicine | Weekly rule | Minimum gap when changing the day | Section |
|---|---|---|---|
| Ozempic®, semaglutide [1] | Same day each week, any time, with or without meals | More than 48 hours (at least 2 days) | 2.1 |
| Wegovy® injection, semaglutide [2] | Same day each week, any time, with or without meals | Last dose 2 or more days before | 2.1; Medication Guide |
| Mounjaro®, tirzepatide [3] | Once weekly, any time, with or without meals | At least 3 days (72 hours) | 2.1, 2.2 |
| Zepbound®, tirzepatide [4] | Once weekly, any time, with or without meals | At least 3 days (72 hours) | 2.3, 2.4 |
| Trulicity®, dulaglutide [5] | Once weekly, any time, with or without food | Last dose 3 or more days before the new day | 2.3, 2.4 |
Why the exact time is worth recording
A weekly schedule looks like a matter of days, but the rules behind it are counted in hours. The day-change limits above are written as 48 or 72 hours, and the missed-dose windows work the same way: 4 days (96 hours) for Mounjaro® and Zepbound®, 5 days for Ozempic®, and a look ahead to the next dose for Wegovy® and Trulicity® [1][2][3][4][5]. The EU documents for Ozempic® and Mounjaro® set at least 3 days between two doses when the day moves [6][7].
None of these rules can be applied to a log that only says “Sunday”. With the date and the clock time of every injection written down, a pharmacist can tell in a minute how a late or moved dose fits your label.
What to log every week
- The date and the clock time of the injection, entered when it happens rather than reconstructed later.
- The injection site, since every weekly label asks for a new spot with each dose [1][2][3][4][5].
- The dose exactly as your prescriber wrote it, so a step up or down shows in the history on the day it started.
- The device: which pen, syringe or vial, and for a multi-dose device the date of its first use and which of its weekly doses this was.
- Anything you noticed that day or in the days after, in a few words, with the date.
- Doses that were skipped or moved, marked as such, so a gap in the log is not mistaken for a forgotten entry.
How many weeks a device lasts
Weekly medicines come in two kinds of device. Single-dose pens and syringes are used once and thrown away; multi-dose pens and vials hold four weekly doses and have a limit that starts on the day they are first used. Counting “week 1 of 4” in your log is the simplest way to see the end coming.
| Device | How many injections | Limit stated in the label |
|---|---|---|
| Ozempic® pen [1] | Four weekly doses per pen (the starter pen also comes as four doses of one strength and two of another) | After first use, 56 days at room temperature or in the refrigerator |
| Ozempic® prefilled syringe [1] | One | Single dose; discarded after use |
| Wegovy® FlexTouch® [2] | Four weekly doses | After first use, up to 56 days at room temperature or in the refrigerator |
| Wegovy® single-dose pen or syringe [2] | One | Up to 28 days at 8–30 °C before the cap comes off, if needed |
| Mounjaro® or Zepbound® KwikPen or multi-dose vial [3][4] | Four weekly doses | Discard after 4 doses, 30 days after first use or 30 days in total at room temperature |
| Mounjaro® or Zepbound® single-dose pen or vial [3][4] | One | Up to 21 days in total unrefrigerated |
| Trulicity® single-dose pen [5] | One | Up to 14 days in total at room temperature |
The weekly check before you inject
- Look at the medicine. The Ozempic®, Wegovy® and Trulicity® labels describe a clear, colourless solution; the Mounjaro® and Zepbound® labels allow clear and colourless to slightly yellow. Particles or an unexpected colour mean the dose is not used [1][2][3][4][5].
- Check the date. The Wegovy® instructions list a passed expiry date among the reasons not to use a pen [2].
- Fit a new needle. The Ozempic® and Wegovy® FlexTouch® labels ask for a new needle for each injection and storage without a needle attached [1][2].
- With vials, use a new syringe and needle each time; the tirzepatide labels give a 1 mL syringe that can measure 0.5 or 0.6 mL as an example [3][4].
- Keep the pen to yourself. Ozempic® (section 5.4), Wegovy® FlexTouch® (5.11) and the Mounjaro® and Zepbound® KwikPen (5.10) must never be shared, even when the needle is changed [1][2][3][4].
Did the injection happen?
The most common gap in a weekly log is not a missed dose but uncertainty about one. The device itself can help: the EU Mounjaro® single-dose pen instructions say the dose was delivered if the grey plunger is visible, and to contact the manufacturer if it is not [7]. Multi-dose pens show a dose counter that the Ozempic® instructions use to confirm the dose [1]. If you still cannot tell, ask your pharmacist before taking another dose; the labels do not describe a top-up.
Logging immediately, in the same place every week, removes most of this doubt. A record made a few days later is better than nothing, but it should carry the real time of the injection, not the time it was typed.
Ozempic® and Wegovy® are registered trademarks of Novo Nordisk A/S. Mounjaro®, Zepbound® and Trulicity® are registered trademarks of Eli Lilly and Company. PepLabo is not affiliated with or endorsed by Novo Nordisk or Eli Lilly and Company.
When to get help
| Sign | Who to contact | How fast | Source |
|---|---|---|---|
| You think you took two doses close together or more than prescribed | Your healthcare provider or Poison Help (1-800-222-1222 in the US; elsewhere your local line) right away | Emergency | Ozempic® Medication Guide [1] |
| Two or more weekly Wegovy® injections were missed in a row | Your prescriber, about how to restart | Today | Wegovy® label, section 2.4 [2] |
| The medicine looks cloudy, coloured or has particles | Do not use it; ask your pharmacist about a replacement | Today | Labels, section 2 [1][3] |
| You cannot tell whether a pen delivered the dose | Your pharmacist or the manufacturer, before any further dose | Today | Mounjaro® EU package leaflet [7] |
| You want to move your weekly day | Your prescriber or pharmacist | At your next appointment | Labels, section 2 [1][3][4][5] |
