The short answer
- For each Mounjaro dose, record the date and time, the strength your prescriber gave you, the injection site and any side effects. Adding weight and notes such as the pen's lot number gives you the full picture.
- The Mounjaro leaflets set rules measured in days: a missed dose can be taken within 4 days, and two doses should be at least 3 days apart if you change your injection day. That's why logging the exact time matters.
- In the UK, Mounjaro comes as a KwikPen holding 4 doses. Once you start a pen, it can be kept out of the fridge for up to 30 days, so it helps to note when you opened it.
- JabKeeper has Mounjaro built in, with the 2.5 mg to 15 mg strengths as presets. It reminds you the day before and on the day, and shows the next injection site in your rotation.
Mounjaro (tirzepatide) is a once-weekly injection, and weekly routines are easy to lose track of. A week is long enough to forget which side you injected and whether you took this week's dose on Sunday or Monday. It's also long enough to lose count of how many doses are left in the pen. A Mounjaro tracker app keeps that history for you, and it's what you'll want in front of you when your prescriber asks how things are going.
This guide covers what to record, the leaflet facts that shape a good diary, and how to set up JabKeeper for Mounjaro on iPhone. We make JabKeeper. Where another method or app suits you better, we say so.
What to track each week on Mounjaro
| What to record | Example | Why it's worth it |
|---|---|---|
| Date and time | Sunday, 7:30pm | Missed-dose and day-change rules are counted in days. |
| Dose strength | 7.5 mg | Shows exactly when each step your prescriber made started. |
| Injection site | Thigh, right | The leaflet asks you to rotate sites with each dose. |
| Side effects | Nausea, moderate, 1 day after | Reveals patterns around dose days and dose changes. |
| Weight | Weekly weigh-in | A trend is more useful than any single reading. |
| Pen notes | New KwikPen, lot number | Tracks the in-use period and identifies the batch if there's ever an alert. |
Mounjaro leaflet facts that shape your diary
Your own prescription and the leaflet in your pack always come first. These points, taken from the official UK and US product information, explain why a careful log pays off. They are not instructions to change anything you've been told.
| Topic | What the label says | What it means for your log |
|---|---|---|
| How often | Once weekly | One entry per week, ideally on the same day. |
| Strengths | 2.5, 5, 7.5, 10, 12.5 and 15 mg | Record the strength of every dose, not just the current one. |
| Injection sites | Abdomen or thigh; the back of the upper arm only if someone else injects | Log the area and side each time. |
| Rotation | Rotate sites with each dose; the UK leaflet says the same area is fine if you use a different spot | Check last week's site before you inject. |
| Missed dose | Take it within 4 days; if more than 4 days have passed, skip it and take the next dose on your usual day | An exact timestamp tells you which case applies. |
| Changing your day | Keep at least 3 days between two doses | Your last injection time shows the earliest new day. |
| UK KwikPen | Multi-dose pen holding 4 doses; after first use, up to 30 days out of the fridge, not above 30°C | Note when you start each pen. |
In the US, Mounjaro is also supplied as single-dose pens and vials, and Zepbound is the brand of tirzepatide licensed there for weight management. The weekly logging routine is the same.
How to set up JabKeeper for Mounjaro
Setup takes a couple of minutes and only happens once:
- Choose Mounjaro from the medicine list. Zepbound, Wegovy and Ozempic are also there, plus an option for other weekly injections.
- Pick the strength you've been prescribed. Mounjaro's 2.5, 5, 7.5, 10, 12.5 and 15 mg strengths are all presets, so there's nothing to type.
- Set your injection day and time, then enter your most recent injection so the countdown to your next dose is right from the start.
- Add your weight, height, goal and weekly pace. You can read your latest weight from Apple Health if you prefer. JabKeeper shows an estimated goal date as a planning aid, not a promise.
Reminders are local notifications on your iPhone. One arrives at your injection time on the day. By default, another comes the day before at the same time, which gives you a chance to check your pen and supplies.
Logging each weekly dose
On injection day, tap Log dose. Your current strength is already selected, the date and time are filled in, and JabKeeper pre-selects the next site in its rotation: the first spot you haven't used in your last five doses. You can change any of these, for example if you injected earlier and are logging it later. If you don't inject into your arms yourself, just choose a different site.
Use the notes field for pen details. Writing "new pen" plus the lot number on the day you start a KwikPen tells you when its 30-day in-use period ends. It also means you can check quickly if a batch alert is issued. In February 2026, for example, the UK medicines regulator warned about falsified Mounjaro KwikPen 15 mg pens sold by one online pharmacy and identified them by batch number.
Weight and side effects on Mounjaro
The free version covers dose logging for your first two records, reminders, the countdown and site rotation. The one-time $9.99 lifetime unlock adds the rest of the diary. There is no subscription.
- Weight progress: log weigh-ins in kilograms or pounds. You get a chart of recent weigh-ins, BMI, your actual weekly rate over the last four weeks and an estimated goal date. There's an optional weekly weigh-in reminder on injection day.
- Side-effect diary: record nausea, fatigue, constipation, headache, injection-site reactions, reduced appetite or heartburn. Each entry has a 1 to 5 severity rating and a note. JabKeeper shows how many days after your last dose each symptom started and summarises the last four weeks. For severe entries, it suggests contacting your prescriber.
- Food and protein: a simple calorie and protein log with daily goals. It isn't a food database, just quick entries for people who want to keep an eye on protein while their appetite is lower.
- Apple Health and Calendar: optionally sync body weight with Apple Health and add your next injection to Calendar. Dose records are never written to Apple Health.
If you're keeping a symptom history for appointments, our guide to keeping a GLP-1 side-effect diary covers what's worth recording and when not to wait for your next appointment.
What JabKeeper doesn't do
JabKeeper is deliberately focused, so it's worth knowing its limits before you commit:
- It tracks one weekly injection at a time. There are no daily schedules, so it isn't suited to daily tablets.
- It has no estimated medication-level chart and doesn't show a titration schedule.
- Weight is in kilograms or pounds. Stones and pounds aren't supported yet.
- It's iPhone only and keeps your diary only on that iPhone. There is no account, cloud sync or backup, so the diary doesn't move to a new phone automatically.
If any of those are deal-breakers, compare the alternatives in Shotsy vs JabKeeper or our roundup of the best GLP-1 tracker apps. If you'd rather not install anything, see app vs spreadsheet vs paper.
Track Mounjaro with JabKeeper
Mounjaro doses, reminders, injection sites, weight and side effects in one private iPhone diary. Free to start, $9.99 once for everything.
Sources
- Mounjaro KwikPen Summary of Product Characteristics, electronic medicines compendium (UK), checked 14 September 2026.
- Mounjaro KwikPen Patient Information Leaflet, electronic medicines compendium (UK), checked 14 September 2026.
- Mounjaro prescribing information, DailyMed (US), checked 14 September 2026.
- Falsified Mounjaro KwikPen 15 mg pre-filled pens, MHRA Drug Safety Update, February 2026.
Frequently asked questions
Is there a Mounjaro tracker app for iPhone?
Yes. JabKeeper has Mounjaro built in, with the 2.5, 5, 7.5, 10, 12.5 and 15 mg strengths as presets, weekly reminders, an injection site rotation and optional weight and side-effect tracking. Other apps, such as Shotsy, also support Mounjaro.
Does JabKeeper tell me when to increase my Mounjaro dose?
No. JabKeeper records the dose you enter and never recommends a dose, a dose increase or a schedule change. Your prescriber decides your dose.
Will JabKeeper remind me the day before my Mounjaro injection?
Yes. By default JabKeeper sends a reminder the day before at your usual injection time, and another at your injection time on the day. Both are local notifications on your iPhone.
Can I track my weight in stones in JabKeeper?
Not yet. JabKeeper records weight in kilograms or pounds.
Does JabKeeper work for Zepbound?
Yes. Zepbound, the US brand of tirzepatide for weight management, is a preset with the same six strengths as Mounjaro.