How to track a GLP-1 protocol properly

A GLP-1 protocol looks like the easiest thing in the world to remember. One injection, once a week, same day. Then a work trip moves it by two days, a dose escalation lands in the same week as a stomach bug, a pen runs out early, and three months later nobody can say with confidence when you moved from 0.5 mg to 1 mg, or whether the nausea started before or after.

That gap matters because almost every decision on a GLP-1 is made from history rather than from a measurement. There is no home test that says how the drug is working. What your prescriber has to go on is your weight trend, your side effects, and the dose you were actually on when each of those happened. A record is not admin: it is the evidence.

The four things worth recording

Most people over-record for three weeks and then stop entirely. The set below is small enough to survive, and it is the set that gets asked about in a review appointment.

The date and time

The single most valuable field, and the one people assume they will remember. It is what makes a gap visible: a fortnight that looks like two doses on a calendar and turns out to be one.

The dose

In milligrams, not in clicks or pen colours. Pens are relabelled, brands differ, and "the blue one" means nothing twelve months later or to a different clinician.

The site

Abdomen, thigh, upper arm, and which side. Rotation is standard advice for subcutaneous injection, and the only way to rotate deliberately is to know where the last one went. See injection site rotation.

How the week went

One line. Nausea, appetite, energy, whether food went down normally. Written the same day, not reconstructed at the next appointment.

Titration is a schedule, not a dose

GLP-1 medications are started low and increased in steps, typically every four weeks, and the step is decided by how the previous four weeks went. That makes the shape of the record more important than any single entry: a prescriber reading it wants to see how long you held at each dose and what happened while you were there.

Two patterns are worth being able to see at a glance. The first is a hold: a month spent at the same dose because the last increase was rough. That is a normal and often sensible thing to do, and it only looks like drift if nobody wrote down that it was deliberate. The second is a gap: a missed week, then a resumption. Restarting after a long gap is not always the same as continuing, and it is a conversation to have with a prescriber rather than a decision to take from a forum.

Why the weekly ones behave differently from the daily ones

Half-life is the reason a missed dose feels different across this class. Semaglutide has a terminal half-life of roughly seven days, which is why it is dosed weekly and why levels move slowly in either direction: it takes four to five weeks at a new dose before the amount in you settles. Tirzepatide sits around five days, dulaglutide around five, and liraglutide around thirteen hours, which is why that one is a daily injection and why a missed day shows up quickly.

The practical consequence is that a weekly compound does not reward precision to the hour and does reward consistency to the day. Moving an injection by a few hours is invisible against a seven-day half-life. Skipping a week is not.

What a level estimate is good for

If you know the dose, the date and the half-life, you can model roughly how much is still circulating. That is what the estimator in Peptain draws, and it is genuinely useful for one thing: seeing the shape of your own protocol. Where the trough sits before the next injection. How long an accidental two-week gap actually takes to recover from. Why the second week after an increase feels different from the first.

Keeping it legible for someone else

The test of a record is whether a clinician who has never seen it can read it in ninety seconds. That means dates in one format, doses in one unit, and side effects written as observations rather than conclusions: "three days of nausea after the 1 mg step" rather than "1 mg does not agree with me". The first is data they can act on, the second is a verdict they have to unpick.

It is also worth keeping the record somewhere that survives a phone upgrade and does not require you to be online at the moment you take the injection. That is most of the argument for a dedicated app over a note: not features, but the fact that the log is still there and still readable in a year. There is a longer comparison in spreadsheet, notes app, or a tracker.