Forgot which day you took Mounjaro? Do this first
Short answer: before doing anything, look for evidence: count your remaining pens, check for a fresh injection mark, and check your pharmacy or delivery dates. If you genuinely cannot rule out having injected in the last few days, do not inject; ask your prescriber or pharmacist first. The real danger is accidentally doubling up, not being a day or two late.
Step 1: check the evidence
- Count your pens or doses. Compare what is left against when the box was started or delivered. This is often enough to work out the last injection date.
- Look at your usual sites. A recent injection often leaves a small mark or slight bruise on the stomach, thigh or arm.
- Check your phone. Photos, messages about jab day, notes, calendar entries. Many people mention their injection to someone the same day.
- Check pharmacy or delivery history. Refill and delivery dates put a boundary on when doses could have happened.
Step 2: know what the label says about missed doses
For Mounjaro (tirzepatide), the manufacturer's instructions say a missed weekly dose can be taken within 4 days (96 hours) of the scheduled time; after that, skip it and take the next dose on your regular day. The instructions also say doses must be at least 3 days (72 hours) apart. That second rule is the important one when you are unsure: if you cannot rule out an injection in the last 3 days, do not inject on a guess. Ask your prescriber, GP or pharmacist how to proceed. This guide describes the label for information only; your prescriber's instructions always take priority.
Step 3: make this the last time you wonder
The stressful part of this situation is not the schedule rules. It is the not knowing. The fix is a record made at the moment of injection, not from memory afterwards:
- Log the dose the moment you take it, before putting the pen away
- Let a reminder tell you when the next one is due, rather than counting days in your head
- Keep the record somewhere that shows date, time, amount and site at a glance
How PepLevel handles it
PepLevel turns dose day into a one-tap ritual: the reminder fires, you tap Log on the notification, and the date, time, amount and injection site are saved before the pen is back in the fridge. Your full history is always there, so "did I take it Thursday or Friday?" becomes a two-second glance instead of a pen-counting investigation. If you did miss a log, you can backdate it, and if you skipped a dose you can record that too, so the record always matches reality.
Never wonder again
One-tap dose logging with reminders, history and injection sites. Coming soon to the App Store.
Get PepLevelMedical disclaimer: this guide is general information, not medical advice. Label information is summarised for reference only and may change; consult the patient information leaflet for your medication and speak to your prescriber or pharmacist about missed or uncertain doses. PepLevel is a logging and reminder tool only.