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Semaglutide reconstitution calculator

Medically reviewed by Juan Pablo Frías, MD · · DisclosureUpdated Educational use only
1Vial size
2Bacteriostatic water added
3Dose per injection
4Syringe (U-100)
Draw to
10units
= 0.1 mL on a 1 mL U-100 insulin syringe
5 mg vial2 mL water0.25 mg dose
Concentration
2.5 mg/mL
Doses per vial
20
Weeks (1 dose/wk)
20
Math only. It does not recommend a dose. Semaglutide: FDA approved (Ozempic, Wegovy, Rybelsus).

10 units (0.1 mL) on a 1 mL U-100 syringe: 0.25 mg from a 5 mg vial + 2 mL water (Semaglutide).

Dosing table for a 5 mg vial

Syringe units (U-100) for each dose, by how much bacteriostatic water you add.

Semaglutide: U-100 syringe units per dose for a 5 mg vial
Dose1 mL water2 mL water2.5 mL water3 mL water
0.25 mg51012.515
0.5 mg10202530
1 mg20405060
1.5 mg30607590
2 mg4080100120
2.5 mg50100125150
5 mg100200250300

How the math works

Concentration is the vial's milligrams divided by the water you add. Volume to draw is your dose divided by that concentration. On a U-100 syringe, 1 mL is 100 units, so units = mL × 100.

5 mg ÷ 2 mL = 2.5 mg/mL
0.25 mg ÷ 2.5 mg/mL = 0.1 mL
0.1 mL × 100 = 10 units

How many units is 0.25 mg of Semaglutide?

With a 5 mg vial and 2 mL of bacteriostatic water, 0.25 mg is 10 units (0.10 mL) on a U-100 syringe. With 1 mL of water it is 5 units. The answer always depends on how much water was added.

How much bacteriostatic water for a 5 mg Semaglutide vial?

The water only sets the concentration; the amount of Semaglutide in the vial stays the same. 2 mL makes 2.5 mg/mL, so 0.25 mg is 10 units. 2.5 mL makes 2 mg/mL, so the same 0.25 mg is 12.5 units. More water makes small doses easier to measure but needs more volume per injection.

How many 0.25 mg doses are in a 5 mg vial?

5 ÷ 0.25 = 20, so 20 full doses of 0.25 mg. Any liquid lost in the needle and vial is not counted.

Preset doses are round numbers for the arithmetic, not dosing guidance. Vial sizes are the ones most often mentioned for Semaglutide in community discussions.

10 units · 0.1 mL · 0.25 mg from 5 mg + 2 mL

Sources

  1. 1Metric (SI) Prefixes (NIST Reference on Constants, Units, and Uncertainty)National Institute of Standards and Technology (NIST) · 2025physics.nist.govAccessed 2 Oct 2026
  2. 2BASAGLAR (insulin glargine) injection, prescribing information (DailyMed)U.S. Food and Drug Administration / DailyMed (Eli Lilly and Company label) · 2026dailymed.nlm.nih.govAccessed 2 Oct 2026

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