Compounded GLP-1 Dose to Units Converter

Compounded GLP-1s come as a vial and a syringe, and the single most common dosing error is mixing up milligrams, millilitres, and syringe units. This tool double-checks the arithmetic between your prescription and your vial label. It never chooses a dose.

Check, don't calculate alone.Use this only to double-check the instructions your pharmacy gave you — never to work out a dose on your own. Your vial's concentration is printed on its label and varies by pharmacy and batch. If this result differs from your pharmacy's instructions, call the pharmacy — do not inject.

Prescribed dose (mg)Milligrams, from your prescription — not units, not mL.Vial concentration (mg/mL)Printed on the vial label (e.g. 1, 2.5, 5, 10mg/mL are all in circulation — read yours, don't guess).

Assumes a U-100 insulin syringe (100 units = 1 mL), the type most compounding pharmacies dispense with vials. If your syringe says anything other than U-100, these unit markings do not apply. mg and units are different things — mixing them up is the single most common compounded-GLP-1 dosing error and the subject of an FDA alert.

Why this exists

Brand pens dial a dose for you; compounded vials make you do the unit conversion, and the FDA has publicly warned about dosing errors with compounded injectable semaglutide — most of them mg-vs-units confusion.
The arithmetic: volume (mL) = dose (mg) ÷ concentration (mg/mL). A U-100 insulin syringe marks 100 units per mL, so units = mL × 100.
Concentration varies by pharmacy and by batch — the same 0.5 mg dose can be 20 units from one vial and 10 from the next. Re-check every new vial.
If this result disagrees with your pharmacy’s instructions, the pharmacy wins until you have spoken to them. Never inject on the strength of a website calculation.