Semaglutide Dosage Calculator
Semaglutide doses are small fractions of a milligram, so the mcg-versus-mg confusion hits harder here than anywhere else. A 0.25 mg starting dose is 250 mcg, and a calculator that reads 0.25 as micrograms will return a draw of zero units.
This page converts a semaglutide vial, whether dry powder or a pre-mixed compounded vial, into the units to draw for each step of the schedule.
FDA labelAn approved product exists and its label states the dose. · Reviewed by the FormBlends Editorial Standards Team · 2026-09-03
FDA labelLabel: 0.25 mg weekly for four weeks, then 0.5, 1, 1.7 and 2.4 mg in four-week steps. Ozempic maximum 2 mg weekly.
Draw to
10 units
0.1 mL
Volume
0.1 mL
1 unit = 0.01 mL on a U-100 syringe
Concentration
2.5 mg/mL
25 mcg in every unit
Doses per vial
20
about 20 days at this frequency
This draw also fits a 0.3 mL syringe, which has finer marks and is easier to read at this volume.
How much water should I use for this dose?
Volumes that put your dose on a printed mark of the 1 mL syringe, inside the accurate part of the barrel.
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FDA compounding status (2026-09-01): Eligible with limits. Component of approved drugs, so 503A compounding is allowed only when the product is not essentially a copy. Full status table and sources
What the Semaglutide dose evidence actually is
Label: 0.25 mg weekly for four weeks, then 0.5, 1, 1.7 and 2.4 mg in four-week steps. Ozempic maximum 2 mg weekly.
Semaglutide has FDA labels. Wegovy escalates from 0.25 mg once weekly through 0.5, 1 and 1.7 mg to a 2.4 mg maintenance dose, holding each step for four weeks. Ozempic uses the same start and tops out at 2 mg. Its half-life is about a week.
Compounded semaglutide follows the same schedule at concentrations that vary by pharmacy, most often 1, 2.5 or 5 mg per mL. Some pharmacies add vitamin B12 or other ingredients, which changes the label but not the semaglutide arithmetic.
Semaglutide units at each water volume
The table uses a 5 mg vial. Each cell is the draw on a U-100 insulin syringe for that dose at that water volume. Cells above 100 units do not fit a 1 mL syringe; cells below 10 units sit in the part of a 1 mL barrel where measurement error rises, and a 0.5 mL or 0.3 mL syringe reads them better.
| Dose | 5 mg + 1 mL5 mg/mL | 5 mg + 2 mL2.5 mg/mL | 5 mg + 3 mL1.667 mg/mL | 5 mg + 5 mL1 mg/mL |
|---|---|---|---|---|
| 0.25 mg | 5 units | 10 units | 15 units | 25 units |
| 0.5 mg | 10 units | 20 units | 30 units | 50 units |
| 1 mg | 20 units | 40 units | 60 units | 100 units |
Worked example: 5 mg with 2 mL is 2.5 mg per mL, so 0.25 mg (0.25 mg, the labelled starting dose) is 10 units, or 0.1 mL.
Mixing Semaglutide
A 5 mg powder vial mixed with 2 mL gives 2.5 mg per mL. At that strength 0.25 mg is 10 units, 0.5 mg is 20 units, 1 mg is 40 units and 2.4 mg is 96 units, which nearly fills a 1 mL syringe. If you are on the higher steps, a stronger mix keeps the draw smaller.
Pre-mixed 1 mg per mL vials put 0.25 mg at 25 units and 2.4 mg at 240 units, which does not fit any insulin syringe. That is why pharmacies move patients to a stronger concentration as the dose rises, and why the units for the same dose change when the vial changes.
Storing Semaglutide after mixing
Follow the beyond-use date on a compounded label. For a powder vial you mixed yourself, refrigerate at 2 to 8 degrees Celsius and treat 28 days after the first puncture as the limit. A 5 mg vial at the 0.25 mg starting dose holds 20 weekly doses, far more than fit inside that window, so most people mix smaller vials or accept discarding leftover.
Semaglutide calculator questions
How many units is 0.25 mg of semaglutide?
Ten units at 2.5 mg per mL. Twenty-five units at 1 mg per mL. Five units at 5 mg per mL, which is hard to measure on a 1 mL syringe. Check your concentration first.
Why does my calculator say 0 units?
Almost always because a milligram dose was entered as micrograms, or the reverse. 0.25 mg is 250 mcg. This calculator lets you switch the dose unit and shows the dose in both so you can catch the mistake.
My new pharmacy vial is 2.5 mg per mL and my old one was 1 mg per mL. What changes?
Your dose stays the same and your units drop. A 0.5 mg dose that was 50 units at 1 mg per mL is 20 units at 2.5 mg per mL. Use the concentration switch mode on this page to convert.
How much bac water for 5 mg semaglutide?
Two millilitres gives 2.5 mg per mL and keeps the early doses at 10 to 40 units. One millilitre gives 5 mg per mL, which is better for the 1.7 mg and 2.4 mg steps but makes the 0.25 mg start a 5-unit draw.
Sources
Semaglutide guide
Evidence, mechanism, side effects and regulatory status.
Semaglutide through FormBlends
Provider review, licensed pharmacy, labelled concentration.
The full peptide calculator
All peptides, pre-mixed vials, blends, mistakes and concentration changes.
Free downloads built from this calculator's math
Peptide Dosing and Reconstitution Chart 2026
20 pages, 12 peptides, every vial size, units at five water volumes, printable vial labels. PDF.
Bacteriostatic Water Cheat Sheet
How much to add, what one unit holds, the 28-day rule stated correctly, four mistakes to avoid. PDF.
28-Day GLP-1 Injection Tracker
Dose, units drawn, site, weight, side effects and the vial counting down. PDF and spreadsheet.
Other peptide calculators
Arithmetic only. This page converts the dose you enter into units and millilitres. It does not recommend a dose. Semaglutide is a prescription medication; follow your label. FormBlends connects patients with licensed providers and pharmacies and does not prescribe or dispense.
