Semaglutide 5 mg Vial: Reconstitution and Dosing Chart

How much bacteriostatic water to add to a 5 mg vial of Semaglutide, the concentration you get, and a full dose-to-units chart.

Medically reviewed by Juan Pablo Frías, MD · 3 Oct 2026 · DisclosureGLP-1 agonistUpdated 3 Oct 2026

Vial size: 5 mg
With 2 mL water: 2.5 mg/mL; common choice
10 units contain: 0.25 mg; at 2 mL, U-100
Whole vial: 200 units; 2 mL on a U-100 scale

How much water to add

Bacteriostatic water only changes the concentration, not the amount of Semaglutide in the vial. More water means more units per dose (easier to read), less water means fewer.

Semaglutide 5 mg vial: concentration by water added
Water added	Concentration	10 units contain	1 mg is	Whole vial
1 mL	5 mg/mL	0.5 mg	20 u	100 u
2 mL	2.5 mg/mL	0.25 mg	40 u	200 u
2.5 mL	2 mg/mL	0.2 mg	50 u	250 u
3 mL	1.667 mg/mL	0.167 mg	60 u	300 u

Calculator and full dosing table

Preset to the 5 mg vial. Change any value; the table below the result updates with it.

1Vial size

2Bacteriostatic water added

3Dose per injection

4Syringe (U-100)

Draw to

40units

= 0.4 mL on a 1 mL U-100 insulin syringe

5 mg vial2 mL water1 mg dose

Concentration: 2.5 mg/mL
Doses per vial: 5
Weeks (1 dose/wk): 5

Math only. It does not recommend a dose.

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
Dose	1 mL water	2 mL water	2.5 mL water	3 mL water
0.25 mg	5	10	12.5	15
0.5 mg	10	20	25	30
1 mg	20	40	50	60
1.5 mg	30	60	75	90
2 mg	40	80	100	120
2.5 mg	50	100	125	150
5 mg	100	200	250	300

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
1 mg ÷ 2.5 mg/mL = 0.4 mL
0.4 mL × 100 = 40 units

40 units · 0.4 mL · 1 mg from 5 mg + 2 mL

Math only. The amounts in these tables are reference values for the arithmetic, not dose recommendations.

Common questions

How much water goes in a 5 mg vial of Semaglutide?

That choice only changes the concentration. With 2 mL, a 5 mg vial is 2.5 mg/mL; with 1 mL it is 5 mg/mL. Less water means fewer units per dose and harder-to-read marks for small doses.

How many units is 1 mg from a 5 mg vial?

With 2 mL of water, 1 mg is 40 units on a U-100 syringe. With other water amounts, see the table.

How many doses are in a 5 mg vial?

Divide the vial size by the dose (in the same unit). The calculator on this page shows the number of whole doses for any dose you pick.

More on Semaglutide

DosageDoses used in published studies, with the source for each.CalculatorVial, water and dose to syringe units.Side effectsWhat labels and studies report, and what is unknown.ResultsStudy outcomes and when they were measured.PricePrice per mg and per week from dated listings. No vendor links.Legal statusFDA, compounding and WADA status with dates.

Sources

1Metric (SI) Prefixes (NIST Reference on Constants, Units, and Uncertainty)National Institute of Standards and Technology (NIST) · 2025physics.nist.govAccessed 2 Oct 2026
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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