Semaglutide Dosage Calculator (mg to Units & mL)
Convert a semaglutide dose in mg to mL and U-100 insulin syringe units for a compounded vial, from the mg/mL on the label or the mg of powder and water you add — with the full titration table and a syringe check.
How it works
concentration (mg/mL) = mg in vial ÷ mL of liquid · volume (mL) = dose (mg) ÷ concentration · U-100 syringe units = mL × 100 · doses per vial = mg in vial ÷ dose
Branded semaglutide pens (Wegovy, Ozempic) deliver a fixed dose, but compounded semaglutide comes in a vial and is drawn up with an insulin syringe, so you must turn milligrams into millilitres and then into syringe "units". On a U-100 insulin syringe 100 units = 1 mL, so units are simply millilitres × 100. The dose itself should follow the Wegovy label titration (0.25 mg weekly for 4 weeks, then 0.5, 1, 1.7 and 2.4 mg). The FDA has reported hospitalisations from people confusing units, mL and mg with compounded semaglutide — always double-check the concentration printed on your vial.
Worked example
A liquid vial labelled 2.5 mg/mL holding 2 mL (5 mg) and a 0.25 mg starting dose: 0.25 ÷ 2.5 = 0.100 mL, which is 10.0 units (0.100 mL) on a U-100 insulin syringe. Each unit holds 25.0 mcg, and the vial holds 20 weekly doses at this dose. At the 2.4 mg maintenance dose the same vial needs 0.960 mL = 96.0 units, more than a 0.5 mL syringe holds.
Sources: Wegovy (semaglutide) prescribing information — Novo Nordisk · FDA: concerns with unapproved GLP-1 drugs used for weight loss
Frequently asked questions
How many units is 0.25 mg of semaglutide?
It depends on the vial concentration. At 2.5 mg/mL, 0.25 mg is 0.1 mL = 10 units on a U-100 syringe; at 5 mg/mL it is 0.05 mL = 5 units; at 1 mg/mL it is 25 units. Units = (dose ÷ concentration) × 100.
What is the semaglutide dosing schedule for weight loss?
The Wegovy label starts at 0.25 mg once weekly for 4 weeks, then 0.5 mg (weeks 5–8), 1 mg (weeks 9–12), 1.7 mg (weeks 13–16) and 2.4 mg from week 17. Ozempic for type 2 diabetes starts at 0.25 mg and goes to 0.5, 1 and up to 2 mg. Your prescriber may move more slowly if side effects occur.
How much bacteriostatic water do I add to a semaglutide vial?
Use exactly the amount your pharmacy or prescriber specifies — the concentration, and therefore every dose, depends on it. Adding 2 mL to a 5 mg vial gives 2.5 mg/mL; adding 1 mL gives 5 mg/mL. Enter the powder mg and the water mL to see the concentration and units.
Is one unit the same as 1 mg?
No. A "unit" on an insulin syringe is a volume mark (0.01 mL), not an amount of drug. How much semaglutide is in one unit depends on the concentration: 25 mcg per unit at 2.5 mg/mL, 50 mcg at 5 mg/mL.
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Educational calculation only, not medical advice. Follow your prescription, the product label and your pharmacist: confusing milligrams, millilitres and syringe units is a common cause of injection overdoses. Use only medicines from a licensed pharmacy.