How GLP-1 Tracking Works
Published Apr 20, 2026 · Updated Sep 11, 2026 · 7 minute read
What a useful GLP-1 or peptide log actually records, and how Peptide Tracker keeps it in one place.
Key Takeaways
- A good log answers four questions: what was taken, when, how much in which unit, and where.
- Keep the planned schedule and the actual log separate so missed and late doses stay visible.
- Record injection sites, side effects, and inventory next to the dose, not in three different apps.
- The app records what you enter. Dose decisions stay with your prescriber and the product label.
KFF found in late 2025 that 12% of U.S. adults were currently taking a GLP-1 drug. Most of them are on a weekly injection, stepping through a titration schedule, rotating injection sites, and watching for side effects. That is a lot of detail to hold in your head, and “I think I took it Tuesday” is not a record a clinician can work with.
A tracker turns that into a timeline. This page covers what belongs in the log and how Peptide Tracker handles each part. Peptide Tracker is the iOS app behind this site; the App Store listing is https://apps.apple.com/us/app/peptide-tracker-calculator/id6744902384.
One boundary, stated once
The app records what you enter. It does not choose a dose, confirm a product is genuine, or decide what to do about a late or missed dose. Those calls belong with your prescriber, your pharmacist, and the product label. The FDA has documented patients drawing up five to twenty times the intended dose of compounded semaglutide, some ending in hospital. A log makes uncertainty visible. It does not resolve it.
The dose log
Every entry needs four things: the compound or product, the date and time, the amount, and the unit. Everything else is context.
A week of entries might look like this:
| Date | Product | Amount | Unit | Site | Note |
|---|---|---|---|---|---|
| Mon 2 Mar, 8:10 am | Wegovy pen | 0.5 | mg | Abdomen, left | First week at this step |
| Mon 9 Mar, 8:30 am | Wegovy pen | 0.5 | mg | Abdomen, right | Mild nausea by evening |
| Wed 18 Mar, 7:45 am | Wegovy pen | 0.5 | mg | Thigh, left | Two days late, travel |
Three rows already show a titration step, a side effect tied to a dose, a site rotation, and a late dose with its reason. That is the whole point.
The unit matters more than people expect. A GLP-1 history can mix milligrams on a pen, micrograms on a compounded vial, and syringe units on an insulin syringe. A log that stores “0.5” without saying 0.5 of what is not a log. Peptide Tracker keeps amount and unit as separate fields on every entry, so a later export never blurs them together.
Context worth adding when it applies:
- Product and source. Brand pen, compounded vial, which pharmacy. Useful when you switch products mid-course.
- Concentration. For reconstituted vials, the mg/mL you worked from. The reconstitution calculator and dose calculator do the math; the log keeps the result.
- Notes. A clinician instruction, a pharmacy question, “felt nauseous by evening.” Dated notes are what make the timeline readable six months later.
Planned versus actual
A reminder says what was supposed to happen. A log says what did. Keep them separate.
Peptide Tracker stores the schedule (cadence, planned date, reminder status) and the logged dose as two different records. When they diverge, that difference is the useful part: a dose logged two days late, a week skipped during travel, a titration step that started earlier than planned. The app surfaces missed scheduled doses over a recent lookback so you can log or skip them, rather than letting the gap disappear.
Titration fits here too. The app can hold a multi-phase schedule with ramp and maintenance steps, but that is a record of the plan your prescriber gave you, not a plan the app generated. For what titration is and why labels set the schedule, see what is dose titration.
Injection sites
Rotating sites is standard advice on every injectable GLP-1 label. Remembering where you injected three weeks ago is not.
The app keeps a site record on each dose: body area, a label for the specific spot, and any reaction you noticed. Over time that gives you a map of which areas were used recently and which have rested. Rest-day counts are shown per area so the next choice is informed rather than guessed.
What it does not do: tell you where to inject, or diagnose a lump, bruise, or rash. Site reactions you note are a record for your clinician, not a verdict.
Side effects
Nausea, constipation, fatigue, injection-site soreness, and appetite changes are the common ones. Most people want to know two things later: when did it start relative to a dose, and did it get better or worse after a titration step.
Logging a side effect next to the dose timeline answers both. Each entry takes a severity, a status (active or resolved), optional photos, what you did about it, and which compound was active at the time. When you review the history with a clinician, the pattern is already laid out.
For serious or unexpected reactions, the FDA’s MedWatch program accepts voluntary reports from patients. Your export can be the record you report from. The app itself never assesses causality.
Inventory
Pens, vials, bacteriostatic water, and oral tablets all run out, expire, or get opened and then sit. The inventory record keeps stock counts, expiry dates, open dates, batch or lot numbers, and source notes per item.
Logging a dose subtracts it from the linked item, and deleting the dose puts it back. Low-stock and expiry warnings show up before a refill becomes urgent. For reconstituted vials, the beyond-use date calculator gives a discard date from the interval you enter.
The inventory record cannot verify that a product is authentic, sterile, or legally sourced. It stores what you know about the item. If a vial’s label and paperwork disagree, the log can hold both facts and the open question.
Half-life curves
The app models how repeated doses overlap using the compound’s reference half-life. DailyMed lists semaglutide at roughly one week and tirzepatide at five to six days. A longer half-life means more overlap between weekly doses and a slower climb to steady state.
The chart is an estimate for education and schedule readability. It is not a blood level, and it does not know your body weight, kidney function, or anything else that changes real exposure. The half-life tracking guide walks through the formula and the common misreadings. The half-life visualizer lets you try the curve without the app.
Exports
An export is where all of this pays off. The app produces PDF, CSV, or plain-text reports filtered by date range and record type, with optional charts and summary stats. Bring one to an appointment and the conversation starts from the record instead of from memory.
A good export reconstructs the timeline: what was logged, when, in which unit, from which vial, alongside any side effects and open questions. If you are weighing an app against a spreadsheet for this, the tracker versus spreadsheet comparison covers where each one breaks down.
Privacy
A GLP-1 log reveals a health condition, a prescribing relationship, medication costs, and body-weight goals. Peptide Tracker stores everything on your device. Optional iCloud sync runs through your own Apple account, and there is no developer-operated server holding your data. Details are in the privacy policy.
9. GLP-1 Tracking FAQ
What does a GLP-1 tracker app do?
It keeps dose dates, times, amounts, units, injection sites, side effects, inventory, and notes in one timeline you can export for a clinician.
Can Peptide Tracker tell me what dose to take?
No. It logs, reminds, calculates, and visualizes. Dose decisions belong with your prescriber and the product label. The FDA has documented hospitalizations from compounded semaglutide dosing errors, which is exactly why the app never guesses a dose for you.
Why track injection sites?
So you can see at a glance which areas were used recently and which have had time to rest. The app does not diagnose skin reactions or tell you where to inject.
Does half-life tracking show my blood levels?
No. It is a mathematical estimate from the reference half-life, about one week for semaglutide and five to six days for tirzepatide per DailyMed. A lab test measures; the chart models.
Where is my data stored?
On your device. Optional iCloud sync goes through your own Apple account. There is no developer-run server holding your logs.