When to Reorder So You Never Run Out

Running out of a GLP-1 is almost never a dramatic event. It is a quiet arithmetic failure: a box that held one fewer week than the month it was asked to cover, a pharmacy that had to order stock before it could fill, and a Thursday morning with no shot to take. This page is about preventing that, and it starts with a piece of arithmetic that almost nobody is told. The neighboring pages cover the neighbors: How Multi-Dose Pens Work, and Counting What Is Left for what is left in one pen, and Medication Shortages: Tracking Through Supply Gaps for a gap that already happened. This one is about the gap that has not happened yet.

Four doses to a box, across the class

The How Supplied sections of these labels are remarkably consistent, and the pattern is four weekly doses to a box. A Wegovy carton contains four single-dose pens, or four single-dose syringes, or one FlexTouch pen holding four weekly doses of 2.4 mg. An Ozempic carton is one single-patient-use pen plus needles: the 4 mg/3 mL pen holds four doses of 1 mg, the 8 mg/3 mL pen holds four doses of 2 mg, and the 2 mg/3 mL pen holds four doses of 0.25 mg and two doses of 0.5 mg, or four doses of 0.5 mg. Zepbound rounds the pattern out from the discard side: its multi-dose vial or single-patient-use KwikPen is thrown away after 30 days at room temperature, 30 days after first use, or after four weekly doses, whichever comes first, even if medicine is left in it.

Twenty-eight days against thirty-one

Here is the part that matters. Four weekly doses is 28 days. A month is 30 or 31. A box does not cover a calendar month, and it never has. Someone who reorders monthly, on the first of the month or on the anniversary of the last fill, is budgeting two or three days that the box does not contain, every single cycle. The refill slips later, then later again, and after a few months it arrives after the dose was due. Nothing went wrong; the units were simply wrong.

The fix is to stop counting in months and count in doses and shot days instead. A dose log already records exactly this: every injection, dated. Counting forward four dated shot days from the day a box opened tells you when the box ends, which tells you when to start asking, which is a fact rather than a feeling about how much is left in the fridge door.

The first boxes behave differently

The exception deserves its own paragraph, because nearly everyone meets it. The Ozempic initiation pen, the 2 mg/3 mL one, holds a mixed count: four doses of 0.25 mg and two doses of 0.5 mg, or four doses of 0.5 mg, depending on the starting schedule. It is the one box in the lineup whose count depends on which schedule it is filling, and it is one reason the first months of refills feel irregular compared with everything after. A dose increase resets the arithmetic in the same way, because the new strength is a different box with its own four doses; The Week After a Dose Increase is the neighboring page for what that week is like.

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Lead time is the other variable

Arithmetic is the controllable half of the problem. The other half is how long a refill actually takes, and that is not under the patient's control. A pharmacy may need to order stock before filling. A prior authorization may be in play, which has its own clock and its own paperwork: see Prior Authorizations: How Your Dose Log Helps the Paperwork. A denial may be under appeal, a process covered at Coverage Denied: How the Appeals Route Works. Mail order adds shipping days on top of everything else, at Mail Order and 90-Day Supplies. None of these can be calculated from home, and all of them can be asked about.

Which is the practical advice, in one sentence: start the refill conversation with doses still in hand rather than on the last one, and ask the pharmacy what their own lead time actually is, because it varies and only they know theirs.

What a log gives you, and what it must not

A dose log does one job here: it turns the calendar into shot days. Dated dose entries mean the next shot day is a fact rather than a guess, and counting forward four of them from the day a box opened tells you when to start asking. That is the whole contribution, and it is enough.

What a log must never become is a rationing tool. Stretching doses to bridge a gap is not a solution. Spacing injections further apart, splitting a dose, or using a pen past its discard date are all dose decisions, and dose decisions belong to the prescriber. If a gap is coming, the conversation is with the prescriber and the pharmacy, before it arrives, not with the calendar afterward. If a gap happens anyway, Missed Your GLP-1 Dose? What the Official Guidance Says and Restarting a GLP-1 After a Break cover what the labels say about the two situations a gap creates.