How much bacteriostatic water do you add to a 2 mg Semaglutide vial?

A common choice is 1 mL, giving a concentration of 2 mg/mL. The exact volume is up to you — more water makes a more dilute, easier-to-measure solution. Use the calculator above to match your target dose to a clean syringe mark.

How many units of Semaglutide do I draw for a 0.25 mg dose?

With a 2 mg vial in 1 mL of BAC water, a 0.25 mg dose is 12.5 units on a U-100 insulin syringe.

GLP-1 agonist

Semaglutide reconstitution calculator

Also known as Ozempic, Wegovy, Rybelsus

Reconstitute Semaglutide by adding bacteriostatic water to the vial, then draw your dose on a U-100 insulin syringe. The calculator is pre-filled with commonly-referenced vial sizes (2, 5, 10 mg) and water volumes (1, 2, 3 mL) — every field is yours to override. Once-weekly GLP-1 receptor agonist. A long ~7-day half-life means levels accumulate over several weeks to steady state.

New to this? How to use the calculator

1Enter what's on your vial. Type the peptide amount (mg) printed on the vial and the mL of bacteriostatic water you mixed in. Not sure how much water to add? Switch to the Solve: water tab and it tells you.
2Enter your dose — mind the unit. Type your target dose and pick mg or mcg with the toggle. This matters: 1 mg = 1000 mcg. GLP-1s (semaglutide, tirzepatide) are usually mg; most peptides (BPC-157, ipamorelin) are mcg.
3Read “Draw to … units”. The big number is how far to pull the plunger on a U-100 insulin syringe. Match it to the fill line on the syringe picture. The concentration and doses per vial are shown so a wrong answer looks wrong.

Three ways to use it

Solve: units — you know the dose; find how far to draw.
Solve: water — you want a round mark like 10 units; find how much water to add.
Solve: dose — you already drew some units; find the dose that was.

Full step-by-step guide

I have a vial, water and a dose — how many units do I draw?

Peptide in the vialmgThe amount printed on the vial label.BAC water addedmLBacteriostatic water you mixed in.

Target dose

Check the unit: 1 mg = 1000 mcg.

Syringe size

U-100 insulin syringe — 1 mL holds 100 units.

Vial cost (optional)$Adds a cost per dose.

Draw to

12.5 units

Concentration: 2 mg/mL
Volume per dose: 0.125 mL
Doses per vial: 8

A U-100 syringe is marked in whole units. The nearest mark is 13 units, which delivers 0.26 mg (your target is 0.25 mg).

Easier-to-read mixes

8 doses per vial either way

Different amounts of water put the same dose on a rounder mark. Tap one to use that water amount.

Want this dose scheduled, checked off daily and tracked by half-life?

Track it for free

This tool computes volumes only — it does not recommend doses. Any pre-filled values are commonly referenced examples to confirm with your provider. Always check the concentration and draw against your own vial and syringe.

Semaglutide concentration quick-reference

Vial	BAC water	Concentration	Units for 0.25 mg
2 mg	1 mL	2 mg/mL	12.5 units
2 mg	2 mL	1 mg/mL	25 units
2 mg	3 mL	0.667 mg/mL	37.5 units
5 mg	1 mL	5 mg/mL	5 units
5 mg	2 mL	2.5 mg/mL	10 units
5 mg	3 mL	1.67 mg/mL	15 units
10 mg	1 mL	10 mg/mL	2.5 units
10 mg	2 mL	5 mg/mL	5 units
10 mg	3 mL	3.33 mg/mL	7.5 units

Example inputs for illustration. Confirm your actual dose with your provider.

Semaglutide has a reported half-life of about 7.0 days. Track how much stays active between doses with a real pharmacokinetic burn-down.

Track Semaglutide in PeptideBuddy

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Related GLP-1 agonist

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