How to Reconstitute Semaglutide
Reconstituting Semaglutidemeans adding bacteriostatic water to the freeze-dried (lyophilized) powder so you can inject a measured dose. If you've just received a vial with a small disc of powder at the bottom, this is where you start.
- Clean the vial stopper with an alcohol swab. Let it dry completely.
- Draw bacteriostatic water into a syringe. We recommend 2 mL for most peptides. Most vials hold 3 mL or less.
- Inject the water slowly into the vial, aiming at the glass wall — not directly onto the powder. This prevents damaging the peptide.
- Gently swirl the vial until the powder is fully dissolved. Do not shake.
- Store in the refrigerator. Most reconstituted peptides last 4–6 weeks refrigerated.
After reconstitution, your vial won't be completely full — that's normal. A typical vial holds about 3 mL, and you're adding 1–3 mL of water. The dose is based on concentration, not how full the vial looks.
How to Draw a Dose
Drawing liquid from a sealed vial requires injecting air first. This equalizes the pressure inside the vial so the liquid flows smoothly into the syringe.
- Clean the vial stopper with a fresh alcohol swab.
- Pull back the plunger to draw air into the syringe — the same volume you plan to withdraw (e.g., if you need 20 units of liquid, draw 20 units of air).
- Insert the needle through the vial stopper and push the plunger to inject the air into the vial.
- Invert the vial so the stopper faces down, with the needle tip submerged in the liquid.
- Pull back the plunger slowly to your target unit mark.
- Check for air bubbles. If you see any, gently flick the barrel to move them toward the needle, then push the plunger slightly to force them back into the vial. Readjust to your target volume.
- Remove the needle from the vial. You're ready to inject.
Semaglutide Dosing Schedule
Semaglutide is a GLP-1 receptor agonist used for weight management and type 2 diabetes. It's injected subcutaneously once per week. The standard titration schedule gradually increases the dose to reduce side effects:
| Weeks | Weekly Dose | Phase |
|---|---|---|
| 1–4 | 0.25 mg | Initiation |
| 5–8 | 0.5 mg | Titration |
| 9–12 | 1.0 mg | Titration |
| 13–16 | 1.7 mg | Titration |
| 17+ | 2.4 mg | Maintenance |
Not everyone reaches 2.4 mg — many people find an effective dose at a lower level. If side effects are significant at any step, stay at the current dose for an additional 4 weeks before increasing.
Understanding Peptide Dosing
The key concept is concentration. When you add 2 mL of water to a 10 mg vial, you get a concentration of 5 mg/mL. To dose 2.5 mg, you need 0.5 mL — which is 50 units on a standard insulin syringe.
Insulin syringes are marked in "units," where 100 units = 1 mL. So the math is simple: multiply the volume in mL by 100 to get your unit mark. The calculator above does this for you automatically.
Frequently Asked Questions
What is the starting dose of semaglutide?
The standard starting dose is 0.25 mg per week for 4 weeks. This low initial dose helps your body adjust and minimizes gastrointestinal side effects like nausea.
How do I convert semaglutide units to mg?
Units on an insulin syringe measure volume, not drug amount. 100 units = 1 mL. To convert: divide units by 100 to get mL, then multiply by your concentration. The calculator above does this automatically.
How long does reconstituted semaglutide last?
When mixed with bacteriostatic water and stored in the refrigerator, reconstituted semaglutide typically lasts 4–6 weeks. Keep the vial upright and avoid temperature fluctuations.