Why your units changed when your dose didn't
If your new vial is a different strength, you may draw a different number of units for the same dose. Here's how to tell and what to do before your next injection.
Belle Answers · Dosing · Updated Oct 11, 2026
Your dose is measured in milligrams (mg). The number of units you draw depends on how strong your vial is, which is its concentration in milligrams per milliliter (mg/mL). So if a new vial is a different strength, the units you draw can change even though your dose stays exactly the same.
Why the strength can change
Vials can come in more than one strength, and the strength can change from one shipment to the next, even from the same pharmacy. It doesn't mean anything about your treatment has changed. It means the math on your syringe has.
How you'll know
- Your patient portal tells you. When a new shipment is a different strength, its shipment page shows a notice that your vial changed strength, with the old strength, the new strength and the exact units to draw now.
- Your label tells you. The directions with your new vial always list the units to draw for your dose.
What to do before your next injection
- Read the label on your new vial before your first injection from it.
- Draw the units the new label says, even if it's a different number than last time.
- If your label, your portal and your plan don't line up, don't guess. Message us before you inject and we'll confirm with your provider.
Learn more
- Dose vs. concentration: why your vial says a bigger number
- How to find your dose and how many units to inject
- My portal or shipment doesn't match my dose plan
Need help? Select Messages in your patient portal (on a phone, tap the chat bubble) or text 877-359-1724.
Education only, not medical advice.