Mounjaro is tirzepatide, injected once a week, and like most weekly injectable medicines, it is supplied in a way that makes it easy to lose track of exactly how much you have left until you are down to your last pen. A simple, consistent way of counting doses can prevent that last-minute scramble and gives you an accurate answer whenever a pharmacy or prescriber asks how you are getting on with supply.
A simple counting system
The details of your specific pen or device, including how many doses it holds and how to tell when it is empty, are set out in your Mounjaro patient information leaflet, and it is worth reading that section once so you know what to look for. On top of that, a basic tracking habit works well for most people:
- Note the date each new pen or pack is started.
- Record each injection date as you go, using whatever weekly log you already keep.
- Keep a running count of injections used from the current pen.
- Note the date you expect to need a new pen, based on how many doses it holds.
- Flag it clearly once you are down to your last one or two doses.
Working out when to reorder
Once you know roughly how many weeks a pen or pack lasts you, you can count backwards from your usual collection or delivery time to work out when to request a repeat prescription or place an order. Building in a small buffer, rather than ordering at the exact point you run out, helps absorb the ordinary delays that can happen with prescriptions, deliveries, or pharmacy stock.
Tracking supply if you use more than one pen at a time
Some people are given more than one pen or pack to have on hand, whether for convenience or because of how prescriptions are dispensed locally. If that applies to you, it is worth logging which pen is currently in use and where any spares are stored, particularly if storage conditions differ between them. Confusing an in-use pen with a spare, or losing track of which one was opened first, is a common source of unnecessary waste, and a simple label or note on each pen alongside your log can prevent it.
A running count is also useful if your routine is ever disrupted by travel, illness, or a change in schedule. Rather than trying to recalculate from memory how many doses you should have left, a log you have kept consistently gives you an immediate, reliable answer.
Disposal and empty pens
Once a pen is finished, your patient information leaflet and pharmacy will have guidance on how to dispose of it safely, usually through a sharps bin rather than ordinary household waste. It is worth keeping a small supply of sharps disposal containers on hand so an empty pen does not sit around waiting for one to become available. Logging the date a pen was finished, alongside starting the next one, keeps your record continuous and makes it easy to check your count is accurate if anything ever looks off.
If your count doesn't match what you expected
Occasionally your own tally and the number of doses you thought a pen should hold will not quite line up, perhaps because a dose felt uncertain, a pen was replaced, or you simply lost track for a week. Rather than guessing or assuming the difference does not matter, write down what you know: the date you noticed the discrepancy, what your log shows, and anything unusual that happened around that time. That note is exactly what a pharmacist needs to help you work out what happened, and it is far more useful than trying to resolve the confusion yourself before asking.
What this tracking is not for
This kind of count is about supply, not dosing. It will not tell you how much medicine should be in a dose, how to use the device, or what to do if a pen looks different from usual; those questions belong with your patient information leaflet, prescriber, or pharmacist. If you are ever unsure whether a pen is working correctly, do not try to work around it by changing how or when you inject. Contact your pharmacy or prescriber instead, and keep your dose log ready so you can tell them exactly when supply became a concern.