Drug facts
Semaglutide dosage in units
Vial in hand? Convert your dose from the concentration on its label, or start at the reconstitution calculator if you are mixing a powder.
Quick answer
Units measure liquid; milligrams measure drug. The starting 0.25 mg dose is 5 units from a 5 mg/mL vial, 10 units from 2.5 mg/mL and 25 units from 1 mg/mL. Semaglutide doses are small, so the marks are small too, and FDA has recorded people drawing ten times the dose they meant. Take the concentration from your own label, every time.
Units, milligrams and milliliters1
A semaglutide dose is prescribed in milligrams, the amount of drug. An insulin syringe measures liquid, and on a U-100 syringe 100 units fill one milliliter. The number that links the two is printed on the vial as milligrams per milliliter: units = mg ÷ mg/mL × 100.
Wegovy users never do this sum. Its single-dose pens each hold one dose, from 0.25 mg in 0.5 mL up to 2.4 mg in 0.75 mL on the standard ladder. Units only appear when the drug comes in a vial.
Semaglutide units chart, by vial strength2
The rows are Wegovy’s dose steps. The columns are three example strengths, since each pharmacy sets its own. Find your dose, then your vial’s mg/mL.
| Dose | 1 mg/mL | 2.5 mg/mL | 5 mg/mL |
|---|---|---|---|
| 0.25 mg | 25 units | 10 units | 5 units |
| 0.5 mg | 50 units | 20 units | 10 units |
| 1 mg | 100 units | 40 units | 20 units |
| 1.7 mg | over 1 mL | 68 units | 34 units |
| 2.4 mg | over 1 mL | 96 units | 48 units |
The weaker the vial, the bigger the mark. At 1 mg/mL the 1.7 mg and 2.4 mg steps need more than one syringe. At 5 mg/mL the whole ladder sits in the bottom half of the barrel, and the starting dose is five small lines.
How many units is 0.25 mg of semaglutide?
5, 10 or 25, depending on whether the vial is 5, 2.5 or 1 mg/mL. That fivefold spread is for the same dose of the same drug. It is also why a reader moving from one seller to another has to start the arithmetic over: what changes when you switch covers the rest.
Where the errors happen3
FDA has an alert on dosing errors with compounded semaglutide, and this conversion is at the center of it. Patients directed to draw 5 units drew 50. One provider meant 0.25 mg, which was 5 units, and prescribed 25; another prescribed 20 units instead of 2. In most reports people took five to 20 times the intended dose, and some were hospitalized. FDA names the causes as unfamiliarity with drawing from a vial, confusion between milliliters, milligrams and units, and vials sold in more than one concentration.
On the label — Wegovy / Ozempic
A pen per dose. The strength is fixed by the manufacturer and there is nothing to convert.
In a compounded vial
A multiple-dose vial whose strength the pharmacy sets. The same milligram dose is a different mark on a different vial, and a remembered number can be wrong on the next one.
Mixing a powder vial: how much bacteriostatic water?5
When a vial arrives as a powder, the water added becomes part of every dose calculation: it sets the mg/mL, which sets every mark in the chart above. Use the volume your pharmacy or prescriber gave you. The reconstitution calculator turns any vial and volume into a concentration and hands it to the units tool.
| Vial | + 2 mL | + 3 mL | + 4 mL |
|---|---|---|---|
| 5 mg | 2.5 mg/mL | 1.67 mg/mL | 1.25 mg/mL |
| 10 mg | 5 mg/mL | 3.33 mg/mL | 2.5 mg/mL |
FDA separately warns against semaglutide sold as a powder “for research purposes,” which it calls of unknown quality. What FDA has said about research vials.
What to check on your own vial4
The label should state the concentration in mg/mL, the total in the vial and a beyond-use date. FDA also asks that patients be given a syringe sized for the dose and shown how to measure it; if you were not, ask. The date is explained under storage and expiry, and the dose steps themselves under the semaglutide dosage chart. Your dose, and any change to it, is your prescriber’s call.
Questions
- How many units is 0.25 mg of semaglutide?
- 25 units at 1 mg/mL, 10 units at 2.5 mg/mL and 5 units at 5 mg/mL, on a U-100 syringe. Read the concentration off your own vial before you use any of these.
- How many units is 1 mg of semaglutide?
- 100 units, a full 1 mL syringe, at 1 mg/mL; 40 units at 2.5 mg/mL; 20 units at 5 mg/mL.
- How many units is 2.4 mg of semaglutide?
- 96 units at 2.5 mg/mL and 48 units at 5 mg/mL. At 1 mg/mL it would be 2.4 mL, which does not fit in a 1 mL syringe.
- Is there a semaglutide dosage chart in units?
- Only per vial strength, because units measure liquid and the label doses are in milligrams. The chart on this page lists the Wegovy dose steps (0.25, 0.5, 1, 1.7 and 2.4 mg) at 1, 2.5 and 5 mg/mL. It converts a dose your prescriber set; it does not set one.
- How much bac water do you add to 10 mg of semaglutide?
- What the dispensing pharmacy or your prescriber specified. The volume decides the strength: 2 mL makes 5 mg/mL, 4 mL makes 2.5 mg/mL. Every syringe mark follows from that choice, so it is not one to guess.
Sources
- U-100 syringe convention; FDA prescribing information for WEGOVY (semaglutide), sections 2 and 3, revision 6/2026 DailyMed
- U-100 syringe convention; concentrations as published by compounding sellers
- FDA drug safety communication, 'FDA alerts health care providers, compounders and patients of dosing errors associated with compounded injectable semaglutide products', content current as of 07/26/2024
- General labeling practice for compounded preparations
- FDA, 'FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss', content current as of 09/01/2026 FDA