Printed on the vial label, for example 2.5 mg/mL.
Syringe size (U-100)
Draw to
10 units
- Your dose
- 250 mcg = 0.25 mg
- Volume
- 0.1 mL
- Concentration
- 2.5 mg/mL
| 5 units | 0.125 mg |
|---|---|
| 10 units | 0.25 mg |
| 20 units | 0.5 mg |
| 30 units | 0.75 mg |
| 50 units | 1.25 mg |
The starting values are examples. Replace them with what is on your vial label and prescription. This tool does the arithmetic only and does not recommend a dose.
Why semaglutide vials cause dosing errors
Brand-name semaglutide comes in pens that measure the dose. Compounded semaglutide usually comes in a vial that you draw up yourself, and that is where mistakes happen. The FDA has warned about dosing errors with compounded semaglutide, including people drawing several times the intended dose after confusing millilitres, milligrams and units.
- mg is the amount of drug. Your prescription is written in mg.
- mL is the volume of liquid.
- Units are syringe marks, 100 to the mL. They are not a dose.
The link between them is the concentration on your label. Concentrations differ between pharmacies and between refills, so the number of units for your dose can change even when the dose does not.
Before you draw
- Read the concentration on this vial, not the last one.
- Confirm the dose in mg with your prescription.
- Compare the result here with the instructions from your pharmacy. If they disagree, call the pharmacy.
This page does not give a dosing schedule. Your dose and any increases come from your prescriber. See the safety notes.
Common questions
How many units is my semaglutide dose?
It depends on the concentration printed on your vial. Divide your dose in mg by the concentration in mg/mL, then multiply by 100. At 2.5 mg/mL, a 0.25 mg dose is 10 units; at 5 mg/mL the same dose is 5 units.
Why did my units change when I got a new vial?
Pharmacies supply different concentrations. The same dose in mg takes a different number of units when the mg/mL on the label changes, so recalculate for every new vial.
Does this apply to Ozempic or Wegovy pens?
No. Pre-filled pens measure the dose for you. This calculator is for vials drawn up with an insulin syringe.