Ozempic Tracker App: Doses, Weight, Side Effects

Four pens, four sets of arithmetic

Semaglutide pens are dial pens. Every detent on the dial advances a fixed volume of about 0.01 ml, not a fixed number of milligrams. What that volume is worth in milligrams depends entirely on the concentration of the pen in your hand, and Ozempic ships in three different concentrations.

Pen	Doses it offers	Concentration	Clicks for a full dose
Ozempic 0.25 / 0.5 mg (3 ml)	0.25, 0.5 mg	0.68 mg/ml	72 to 0.5 mg
Ozempic 0.25 / 0.5 mg (1.5 ml, older)	0.25, 0.5 mg	1.34 mg/ml	36 to 0.5 mg
Ozempic 1 mg	0.25, 0.5, 0.75, 1 mg	1.34 mg/ml	72 to 1 mg
Ozempic 2 mg	0.5, 1, 1.5, 2 mg	2.68 mg/ml	72 to 2 mg

All four hold four labelled doses and may be used for 56 days once started. Click counts are a community reference, not manufacturer guidance – the full picture is in the pen click chart.

Read the first two rows again, because that is the trap. Both pens are labelled “0.25 / 0.5 mg” and both look almost identical. The 1.5 ml version, phased out from 2023 but still around, is twice the concentration of the 3 ml pen sold today. The same 0.25 mg dose is 18 clicks on one and 36 on the other.

Penwise asks which pen you have and does the arithmetic from the concentration rather than from a number someone posted on a forum. It also converts in the other direction, so if you are working from clicks you can see what that is in milligrams on your specific pen.

Where you are in the week, not just when you injected

Semaglutide has an elimination half-life of about seven days – longer than tirzepatide, and long enough that a single dose is still doing something a fortnight later. A weekly shot lands on top of roughly half of the previous one, and it takes four to five weeks on a stable dose before the weekly rhythm settles.

That long tail is why the semaglutide experience is flatter than the tirzepatide one. It is also why the first four weeks after a dose increase feel like they are still building, because they are: the average level is climbing towards a new plateau the whole time.

Penwise+ draws that curve from the doses you actually logged, using published absorption and elimination rates. The detail is in how long Ozempic stays in your system. It is an estimate from a model, never a measurement of your blood, and it never suggests a dose.

Fifty-six days, counted down

An Ozempic pen may be used for 56 days after the first injection. That is eight weeks, which lines up neatly with four weekly doses plus a buffer – until you are between strengths, or you skipped a week, or you are stretching a pen. Then the two clocks come apart and the discard date arrives before the liquid runs out.

Penwise counts both. It knows how many labelled doses are left at your current dial setting, how many days that is, and whether that number is longer than the pen is allowed to last. When it is, it says so, because that is the exact situation people only discover in hindsight. There is more in how long a GLP-1 pen lasts.

The dose ladder, and what happens when you step off it

The usual Ozempic path is four weeks at 0.25 mg, then 0.5 mg, then upwards as needed to 1 mg and, on the 2 mg pen, to 2 mg. Some people stay at 0.5 mg indefinitely. Some go up and come back down. Some hold a dose for months because it is working and the side effects are tolerable.

Penwise records the schedule you are actually on rather than an ideal one, and lets you skip, postpone or reschedule any single dose while keeping the history of what you decided. When a dose is late, it stays visible as late instead of quietly disappearing. Dose schedules and titration covers the ladders for every product.

Side effects, tied to the point in the cycle

Semaglutide side effects tend to be worst in the days after a dose increase and to settle as the body adjusts. Nausea, reflux, constipation, fatigue and the sulphur burps are the usual list, and the useful question is never whether you had them but when.

Penwise tracks twenty named side effects on a 0 to 5 scale alongside nine sliding measures – appetite, fullness, food noise, three kinds of craving, energy, mood and sleep – and looks for the timing across your own history. If nausea reliably lands two days after your shot, that is something you can plan around. If there is not enough history to be confident, the app says nothing rather than inventing a pattern. See the GLP-1 side effect timeline.

Weight, and reading it against the dose

A weight chart on its own tells you very little. The same chart with the dose history laid against it tells you whether a stall started when you plateaued at 0.5 mg or three weeks before, and whether the drop after an increase was the increase or a week of being unwell.

Penwise keeps weight, body fat, lean mass, waist and resting heart rate together with the dose log, with a goal weight and progress against it. Everything charts, everything exports, and Apple Health or Health Connect can feed the weight in automatically if you already weigh on a connected scale.

Your log stays on your phone

There is no Penwise account, no sign-in and no server that receives health data. Your semaglutide history, your weight and your symptoms live in the app on your device. No ad networks, no attribution SDKs, no third-party analytics on any of it.

The only copy that leaves the phone is a backup you export yourself, encrypted on the device with a passphrase we do not hold. CSV and JSON export is free forever, because your own history should never sit behind a paywall. If that is the part that matters to you, read why a GLP-1 tracker should not have a server.

Track Ozempic without handing your history over

Free core tracker, no account, nothing sent anywhere. Fourteen days of Penwise+ included, no card needed.

Download on the App Store Get it on Google Play

Common questions

Is there a free Ozempic tracker app?

Yes. The core of Penwise is free forever: logging semaglutide shots with dose, site, pain and notes, weight tracking, site rotation on a body map, history and calendar, dose reminders, and full CSV and JSON export. Penwise+ adds estimated medication levels, insights, health-platform sync and doctor-ready PDF reports, with a fourteen-day trial that needs no card.

Which Ozempic pens does Penwise know?

All four: the 0.25 / 0.5 mg starter pen sold today, the older 1.5 ml starter pen, the 1 mg pen and the 2 mg pen, each with its own concentration and dose ladder. It also handles Wegovy pens, Rybelsus tablets and compounded semaglutide vials.

How many clicks is 0.25 mg of Ozempic?

It depends on the pen. On the 3 ml starter pen sold today, a full 0.5 mg dose is about 72 clicks, so 0.25 mg is about 36. On the older 1.5 ml starter pen, which is twice as concentrated, 0.5 mg is about 36 clicks and 0.25 mg about 18. Penwise works it out from the pen you tell it you have. Manufacturers advise against dosing by clicks.

How long does an Ozempic pen last after the first use?

The manufacturer allows 56 days of use after the first injection, whatever is left in it. Penwise counts that down alongside your remaining doses and warns you when your dosing plan would outlast the pen. Confirm storage guidance for the product you were dispensed with your pharmacist.

Can Penwise estimate how much Ozempic is in my system?

Penwise+ models it from the doses you logged, using published absorption and elimination half-lives for semaglutide. It is an estimate from a pharmacokinetic model, not a measurement of your blood, and the app never presents it as a clinical value or uses it to suggest a dose.

Does Penwise work if I am on compounded semaglutide?

Yes. Enter the vial concentration and Penwise converts a dose in milligrams to units on a U-100 syringe, and back. Five common vial presets are built in and you can add your own.

Is Penwise connected to Novo Nordisk?

No. Ozempic, Wegovy and Rybelsus are trademarks of Novo Nordisk A/S. Penwise is an independent tracker published by Version Two s.r.o., is not affiliated with, endorsed by or sponsored by Novo Nordisk, and does not sell, supply or prescribe medication.

Sources

Every factual claim on this page traces to the product information a regulator publishes, or to a published trial. Links open on the site of whoever issued the document.

Ozempic: EPAR product information European Medicines Agency
Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes (SURPASS-2) New England Journal of Medicine, 2021
Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes (SELECT) New England Journal of Medicine, 2023

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.

The Ozempic tracker that knows which pen you are holding