Start with what you will still want in six months
Nearly everyone starts by logging a date, and nearly everyone finds within two months that a date is not the question. The questions that arrive later are the ones to buy for: which site hurts less, which day the nausea lands, whether the dose is still doing what it did, how many days of pen are left, and what to show a prescriber.
An app that only does dates cannot grow into those. So the first question is not “is it easy to log a shot” – they all are – but “will this answer a question I have not thought of yet”.
The twelve questions
1. Does it record the time of the shot, not just the date?
A Monday morning and a Monday night injection are twelve hours apart on the level curve. Every timing pattern you might later want depends on this, and an app that stores only a date has thrown it away permanently.
2. Does it model your medication level, or just count days?
The difference between “your last shot was Tuesday” and “you are on the downslope” is the difference between a log and a tracker. If it does model a level, ask what it is: a real pharmacokinetic model with per-medication half-lives, or a generic curve applied to everything. Semaglutide and tirzepatide behave differently enough that one curve for both is simply wrong. See tirzepatide and semaglutide half-lives.
3. Does it know your medication, or just accept a name?
Typing “Mounjaro” into a text field is not support. Support means the app knows the dose ladder, the cadence, the half-life and the devices. Ask whether it handles oral doses as a proper route – hiding site and pain fields, switching to a daily schedule – or bolts tablets onto an injection form.
4. Does it understand pens as objects?
This is the sharpest test of depth, because anybody can build a date picker. Does it know how many clicks a full dose is on your specific pen, that a click moves a fixed volume rather than fixed milligrams, how long the pen may be used once started, and how many days of supply you have at the dose you are actually on? See the pen click chart and discard windows.
5. Does it rotate injection sites for you?
A body map is table stakes. What matters is whether it suggests the least recently used site and stores a pain score per site, because that is what turns a year of shots into an answer about your own body rather than a list. See injection sites.
6. Can it record how you felt, in a way that can be analysed?
Free-text notes are unsearchable and unanalysable. Scored side effects and scored measures – appetite, fullness, food noise – can be plotted against the dose cycle. If the app cannot tell you which day after a shot a symptom tends to land, it is a diary.
7. Does it say something only when it has evidence?
An app that reports a pattern from three data points is worse than one that says nothing, because you will believe it. Ask whether insights have a minimum evidence threshold. Quiet is a feature.
8. Where does your data actually live?
This is the question people ask last and should ask first. Does it require an account? Is your medication history stored on a server? Which analytics and advertising SDKs are in the app? What is the retention policy, and what happens to the data if the company is acquired or closes?
An app with no server cannot leak, sell or be compelled to hand over what it does not have. An app with a server may be run by entirely decent people and still be a different risk profile. Both are legitimate choices – but make it a choice rather than a default. See why a GLP-1 tracker should not have a server.
9. Can you get your data out, free?
The single best test of whether an app respects you. Export as CSV or JSON, complete, without a subscription. If your own history is behind a paywall, you are renting your medical record from someone.
10. Can you get your data in?
If you are switching, can it import from where you are? And is the import careful – does re-importing the same file duplicate everything, does it detect date formats and separators rather than assuming, can the whole thing be rolled back? See switching from Shotsy.
11. What does the appointment look like?
At some point you will want to show a prescriber what has been happening. A PDF with dose history, weight trend, adherence and recorded side effects, dated and legible, is worth more than a phone screen scrolled quickly across a desk.
12. What does it really cost?
Compare the yearly price rather than the monthly one, check whether there is a lifetime option, and check what the free tier actually keeps working. Then check what happens if you stop paying – whether the app becomes read-only, whether export still works, and whether your history survives at all.
The categories, honestly
A notes app or a spreadsheet
What most people on GLP-1 medication actually use, and it is free and completely under your control. It cannot rotate sites, cannot remind you, cannot chart anything without work, and cannot answer a timing question. Fine for three months; poor for three years.
A general health or fitness app
Good at weight and steps, unaware of what a titration schedule is, what a KwikPen is, or what food noise means. It will happily let you log a dose in the wrong units.
A dedicated GLP-1 tracker
The category this checklist is about. They differ far more than their screenshots suggest, and the differences are mostly in questions four, seven, eight and nine.
A clinic or telehealth app
Convenient if you get your prescription there, and worth reading carefully on the data question: the organisation holding your log is also the one selling you the medication.
Where Penwise lands
Since we wrote the questions, here are our answers, including the uncomfortable ones.
- Time of shot: recorded. Level: modelled per medication with published half-lives. Pens: seventeen, with click counts, in-use windows and days of supply.
- Sites: body map with least-recently-used suggestion and pain per site. Check-ins: twenty side effects and nine measures. Insights: evidence thresholds, quiet by default.
- Data: no account, no server, no ad SDKs, no third-party analytics on health data. Export: CSV and JSON, free, forever. Import: Shotsy, reversible.
- Reports: doctor-ready PDF and a clinical-standard export. Price: free core tracker; 2,49 € monthly, 19,99 € yearly, or 59,99 € once.
- What we do not have: cloud sync, a web app, cross-device history, or a password reset – all consequences of having no server. No direct integrations with Garmin, Withings, Dexcom or Libre, though their data can arrive through Apple Health or Health Connect. No calorie database. Sleep, steps, glucose and heart rate variability are not tracked; resting heart rate is.
If cloud sync across devices is a requirement for you, we are the wrong app and we would rather say so here than have you find out in week three.
Run the checklist on us
Free core tracker, no account, full export from day one. Fourteen days of Penwise+ with no card.
Common questions
What should a GLP-1 tracker record beyond the date?
Do I need an app that estimates medication levels?
Is a free GLP-1 tracker good enough?
Should I worry about where my medication history is stored?
Can I move between trackers later?
Is this comparison impartial?
Penwise is a tracking and education tool, not a medical device. Nothing on this page is medical advice, a diagnosis or a recommendation to start, stop or change a dose. Dosing decisions belong to you and your clinician. Ozempic, Wegovy, Rybelsus, Saxenda and Victoza are trademarks of Novo Nordisk; Mounjaro, Zepbound and Trulicity are trademarks of Eli Lilly. Penwise is not affiliated with, endorsed by or connected to either company.