Quick answer: To reconstitute Semaglutide, add bacteriostatic water to the vial. Concentration = vial size (mg) ÷ water (mL). A 5mg vial in 3mL is 1.7 mg/mL, so a 1mg dose = 60 units on a U-100 syringe. Change any value above to rebuild the chart for your vial.
How to reconstitute Semaglutide
Reconstitution is the step where you turn a lyophilized (freeze-dried) Semaglutide vial into an injectable solution by adding bacteriostatic water (sterile water with 0.9% benzyl alcohol added as a preservative). The amount of water you add does not change your dose in milligrams; it changes the concentration, which is what decides how many units you draw on the syringe. That is why two people on the exact same 1mg dose can draw completely different unit amounts.
Add the water slowly down the inside wall of the vial, let the powder dissolve without shaking, and store the reconstituted vial as described below. The calculator above and the chart rebuild instantly for whatever vial size and water volume you choose, so you can compare concentrations before you mix.
Semaglutide reconstitution reference (5 mg vial)
| Dose | 5.0 mg/mL (5mg + 1mL) |
2.5 mg/mL (5mg + 2mL) |
1.67 mg/mL (5mg + 3mL) |
|---|---|---|---|
| 0.25 mg | 5.0 units (0.05 mL) | 10.0 units (0.1 mL) | 15.0 units (0.15 mL) |
| 0.5 mg | 10.0 units (0.1 mL) | 20.0 units (0.2 mL) | 30.0 units (0.3 mL) |
| 1 mg | 20.0 units (0.2 mL) | 40.0 units (0.4 mL) | 60.0 units (0.6 mL) |
| 1.7 mg | 34.0 units (0.34 mL) | 68.0 units (0.68 mL) | 102.0 units (1.02 mL) |
| 2.4 mg | 48.0 units (0.48 mL) | 96.0 units (0.96 mL) | 144.0 units (1.44 mL) |
This static table shows a 5mg vial at a few common water volumes. For any other vial, use the live chart above.
Storing Semaglutide after reconstitution
Once reconstituted, store the vial refrigerated (2-8°C). Reconstituted GLP-1 peptides are typically stable for roughly 28 to 60 days depending on the compound and the preservative in your bacteriostatic water. Do not freeze a reconstituted vial, keep it out of direct light, and discard it if the solution becomes cloudy or shows particles.
Worked example
Take a 5 mg vial and add 1 mL of bacteriostatic water. That gives 5.0 mg/mL. For a 1 mg dose: (1 ÷ 5.0) × 100 = 20.0 units on a U-100 syringe (0.2 mL). Draw to that mark.
Frequently asked questions
How much bacteriostatic water do I add to a Semaglutide vial?
There is no single correct volume. The water sets the concentration, not the dose. More water makes small doses easier to measure but uses more of the syringe. A 5mg vial in 3mL gives 1.7 mg/mL. Enter your own numbers above to compare.
How do I read my Semaglutide reconstitution chart in units?
Find your concentration (vial mg ÷ water mL), then units = (dose ÷ concentration) × 100. The chart above does this for every common dose at your exact concentration.
How long does reconstituted Semaglutide last?
Refrigerated at 2-8°C, most reconstituted GLP-1 peptides stay stable for about 28 to 60 days. Never freeze a reconstituted vial and discard it if it turns cloudy.
Safety: Semaglutide is the active ingredient in FDA-approved GLP-1 medications. This tool is educational only. Always double-check your own math and follow a licensed provider's instructions before injecting.