How to Track GLP-1 Vials, Pens and Refills
A system for knowing how much medication you have left, when a vial expires, and when to reorder — so you never discover the problem on shot day.
Why this is worth a system
Most people tracking a GLP-1 track the treatment and not the supply. Then one Thursday there is not enough left in the vial for a full dose, the prescription needs renewing, and the pharmacy needs three days.
Running out is not just an administrative annoyance. It puts a gap in a schedule that works best when it is regular, and it is entirely preventable with about thirty seconds of record-keeping per shot.
There are three separate things to track, and they fail in different ways:
- How much is left — the volume problem.
- How long it has been open — the time problem, which can expire a vial that still has medication in it.
- When to reorder — the lead-time problem, which is the one that actually bites.
Step 1: record what arrived
When a new supply comes in, write down four things: the date you received it, what it is, the total strength in the vial or pen, and the date printed on the label.
Total strength is the one people skip, and it is the one the arithmetic depends on. A pen or vial's label tells you the total amount it contains; your dose tells you how much of that you use each week. Everything else follows from those two numbers.
If you have more than one vial in the fridge — common once you are ordering ahead — give each one an identifier. "The one from March" is not an identifier once there are three.
Step 2: note the date you first pierced it
This is the field people most often miss, and it is the one that matters most for safety.
For a multi-dose vial, the in-use clock generally starts when you first puncture the stopper, not when the box arrived and not when it was manufactured. A vial can sit unopened well inside its printed expiry and then have a much shorter window once it is in use.
So record the first-puncture date separately from everything else. If you are reconstituting a lyophilised product with bacteriostatic water, the same applies to the water — the commonly cited in-use window after first puncture is 28 days, and it runs from that puncture regardless of how much is left.
The in-use window that applies to your product is the one your pharmacy gave you. These limits differ between manufactured pens, compounded vials and reconstituted preparations, and general internet numbers are not a substitute for the label. If it is not clear, ring the pharmacy and ask — they will tell you, and it takes two minutes.
Step 3: subtract each dose as you take it
The core of the system is a running total, and the important detail is which number you keep.
Track the amount remaining, not the number of doses left. Doses left is the intuitive way to think about it and it quietly becomes wrong the first time you titrate. A vial with four 2.5 mg doses left has one and a bit 7.5 mg doses left, and if you have been counting shots rather than milligrams you will not notice until the plunger stops.
So log the dose against the specific vial each week and keep the remaining amount current. If you are drawing from a vial with a syringe, the units you draw for a given dose depend on the concentration you reconstituted at, which is the same arithmetic your remaining-amount sum depends on.
Two practical notes:
- Overfill is not a bonus. Pens and vials often contain slightly more than the labelled amount for priming and draw losses. Plan against the labelled amount and treat anything extra as margin.
- Log the waste too. A dose you spoiled, a priming shot, a draw that went wrong — those milligrams left the vial as surely as the ones you injected.
Step 4: set the reorder point, not the empty point
Work out which shot is your last from this supply, then put the reminder at least two weeks earlier.
Two weeks sounds generous until you count what has to happen in it: a prescription may need renewing, which may need an appointment; the pharmacy needs to fill it; a compounding pharmacy may need to make it; and any of those can hit a shortage. Titration makes it worse, because stepping up shortens the supply — the vial you thought would last six more weeks lasts four at the new dose.
If you are titrating, recalculate the reorder date at every increase. That is the single most common way a carefully planned supply runs short.
Your titration schedule is the natural place to keep this, because the dates that change your consumption are already written on it.
Step 5: check the discard date before every shot
Make it part of the routine, in the same motion as checking the dose.
Two questions, both quick. Is there enough in this vial for a full dose? And is this vial still inside its in-use window?
The second one is the one worth building the habit around, because it is the failure that does not announce itself. A vial that is low is visibly low. A vial that has been open too long looks exactly like a vial that has not.
If the answer to either is no, that is a conversation with your pharmacy rather than a judgement call to make at the fridge.
What this looks like written down
The whole system fits in a few fields per vial:
| Field | Example |
|---|---|
| Identifier | Vial B |
| Received | 12 March |
| Total strength | 10 mg |
| First pierced | 20 March |
| Discard by | per pharmacy label |
| Remaining | 5.0 mg |
| Last shot from it | 17 April, 2.5 mg |
| Reorder by | 1 May |
Updating it takes about as long as the injection does. The value is that "how much do I have left" and "when do I need to order" stop being estimates you make under mild pressure on a Thursday evening.
A note on storage
Storage requirements differ by product — some need refrigeration until first use, some tolerate room temperature for a defined period afterwards, and the specifics vary between manufactured and compounded preparations.
Whatever yours requires, it is worth recording any excursion: a fridge that was left open, a bag that sat in a warm car, a delivery that arrived warm. Not because you can adjudicate it yourself, but because it is the first thing the pharmacy will ask about, and "some time last week, I think" is a much worse answer than a date.
This guide is about record-keeping. Storage limits, in-use windows and what to do about a compromised vial are questions for your pharmacy or provider, and their answer about your specific product is the one to follow.