GLP-1 Injection Site Rotation: How to Track Which Site You Used Last

Remembering last week's site is a record-keeping problem with a boring, reliable fix. Where to inject stays between you and your prescriber.

LockedIn is a tracking tool, not medical advice. It does not verify what you enter, and it does not recommend doses, schedules, or intake targets. Dose and medication decisions come from your prescriber. Nothing on this page is a substitute for their instructions.

Write it down at the moment you inject, and rotate in a fixed order so the next site is decided by the last one rather than by memory. Those two habits only work together. The written record tells you where you stopped, and the fixed order tells you what comes next, so there's nothing to reconstruct a week later while you're standing there holding the pen.

The minimum useful entry is three things: the date, the dose, and a short label for the site you used. That can live on a paper calendar, in a note on your phone, or in an app that keeps the sequence for you. What matters more than the format is that you record it in the same ten seconds you take the dose, not that evening when the detail has already gone soft.

One thing to be clear about before anything else: which areas are appropriate for your medication, and how to give the injection, come from your prescriber and from the instructions for use that came in the box with your pen or vial. I build a tracking app, so this page covers record-keeping only. It's not medical advice and shouldn't override what your prescriber told you. Rotation itself is standard guidance in the manufacturer instructions for the common GLP-1 pens, and those instructions are where your site list should come from.

Why last week's site is so hard to recall

A weekly injection is a twenty second event wedged between coffee and the rest of a Sunday morning. There's nothing memorable about it by design, and after a couple of days there's usually no physical trace either. Five to seven days is a long gap for an unremarkable memory to survive intact.

The failure mode is usually a confident wrong answer rather than a blank. You're fairly sure it was the left side last time, and being fairly sure isn't the same as knowing. When you can't recall at all, the fallback is the same convenient spot you always reach for, which quietly undoes the point of rotating in the first place.

Titration weeks make it worse. When the dose is changing you're already tracking a new number, sometimes a new pen and a new schedule, and the site is the first small detail to fall off the list.

Pick a fixed order and the next site picks itself

The bookkeeping trick is to stop treating each dose as a decision. Decide once on a repeating sequence of the sites your instructions allow, number them, and always take the next number in the list. Now there's only one fact to carry from week to week, which is where you stopped, and you're writing that down anyway.

The math is the whole benefit. With four positions in the loop and a weekly dose, each position comes back around roughly once a month. With eight positions it's once every two months. A sequence plus a last index is a closed problem you can answer in a second. Where have I been lately is an open one that gets harder every week.

Which areas belong in your loop is not my call and not the internet's. Your prescriber and the instructions for use that came with your medication define that list, including how many positions it should have. This page is about keeping the ledger. Your prescriber draws the map.

What to write down, and what to skip

Keep each entry short enough that you'll still be doing it in month seven.

Skip the rest. The elaborate logs are the ones I stop keeping. A rough log you keep for a year is worth more than a beautiful one you kept for three weeks, because the only question you're ever asking it is which position comes next.

Where each method breaks

Every way of doing this works fine on a calm week at home. The differences show up on the bad weeks.

MethodHolds up whenFalls apart when
Wall calendarYou dose at home on a steady routineYou travel, or someone tidies the kitchen
Note on your phoneYou're strict about the formatEntries get typed hours later from memory
SpreadsheetYou already live in spreadsheetsYou're standing in a bathroom at 7am
Dose log in an appSite, dose, and date go in as one entry and the next site is suggestedYou don't open the app that day

None of these is clever. The one that wins is the one you can complete in under ten seconds without deciding anything.

Where the record earns its keep

Appointments. "When did you move up, and how have the weeks since gone?" is a question you can answer in five seconds from a dated list and not at all from memory. If your log also carries your weight over the same period with the dose changes marked on it, the conversation gets shorter and a lot more concrete.

Travel. A different time zone and an unfamiliar bathroom is exactly where a routine that lived in your head quietly stops existing.

Shared administration. If a partner or a family member sometimes helps, a written sequence is the only way two people stay on one rotation instead of two overlapping ones.

Late or missed doses. What to do about a missed dose is a question for your prescriber, and the first thing they'll ask is when the last one was. Have the date ready rather than a guess.

What a rotation log will not do

It won't tell you whether a site is appropriate for you, and it can't evaluate anything you notice at a site afterward. If something looks or feels off where you injected, that's a call to your prescriber, and so is anything about your dose or your medication.

A rotation log is a memory aid for three fields: date, dose, position. That's the entire job. It's worth doing because the alternative is a guess every week, and a guess tends to land on the same spot you always use.

How LockedIn handles this

I built the GLP-1 section of LockedIn around this exact problem. You log a dose with the date, the amount, and the injection site, and the app handles the rotation so the next position is already picked when you open it. Dose-day reminders cover the other half of the problem, which is remembering to take it at all. If you're titrating, you can set up a titration plan and see your doses plotted directly on your weight trend, so a dose change and the weeks after it sit on the same chart instead of in two different places. There's also a reconstitution calculator that turns vial mg plus bacteriostatic water mL into units on a U-100 syringe. LockedIn runs on iPhone and in a browser, and it's free while it's in beta.

Try it in the browser

Common questions

How do I remember which injection site I used last?

Record it at the moment you inject, using the same short label every time, and rotate through a fixed numbered order so the next site is determined by the last one. Then the only thing you need to know is where you stopped, and that's written down.

How often should GLP-1 injection sites be rotated?

Rotation guidance for your specific medication comes from your prescriber and from the instructions for use that came with your pen or vial. Those documents are the source for how often to rotate and which areas to include, not general advice online.

What should I write down for each GLP-1 dose?

The date, the dose in milligrams, and a short consistent label for the site. Add one line if there's something you want to raise at your next appointment. Keep it brief so you're still doing it six months from now.

Is a note on my phone good enough for tracking rotation?

It works if you keep the format identical every week and write the entry at the time of the dose. The two things that break phone notes are inconsistent site labels and entries added hours later from memory.

Does LockedIn track injection sites?

Yes. LockedIn logs GLP-1 doses with the injection site attached, rotates through your sites so the next one is already selected, sends dose-day reminders, and plots your doses on your weight trend. It's free while the app is in beta.

Track it instead of guessing at it

LockedIn puts food, GLP-1 doses, workouts and weight in one place. Free while it is in beta.