Semaglutide Mixing Chart: Every Vial Size (2026)

The 3 mg vial is the smallest standard size. It provides limited doses before requiring a new vial, best suited for the initial titration weeks.

Recommendation: Add 1.5 mL for a 2.0 mg/mL concentration. This gives clean 12.5 IU increments for the 0.25 mg starting dose and 25 IU for 0.5 mg. Both are easy to read on a U-100 insulin syringe.

The 5 mg vial is the most popular size for the initial 8-week titration (4 weeks at 0.25 mg + 4 weeks at 0.5 mg). One vial at the right dilution covers this entire period.

*120 IU exceeds the capacity of a standard 100 IU syringe. Use a 1 mL syringe or split into two injections.

Recommendation: Add 2 mL for a 2.5 mg/mL concentration. At this dilution, 0.25 mg = 10 IU and 0.5 mg = 20 IU. These are the cleanest measurements on an insulin syringe. This is the most commonly used mixing ratio for semaglutide. For a deeper dive, see our how much bacteriostatic water for semaglutide guide.

The 10 mg vial is the most cost-effective option for ongoing treatment. It provides enough semaglutide for 8-20+ weeks depending on dose.

Low volume (2 mL): Higher concentration means smaller injection volumes. Better for men who want minimal fluid under the skin. Harder to measure very small doses accurately.

High volume (4-5 mL): Lower concentration means easier measurement at low doses. Larger injection volume. Good for the 0.25-0.5 mg starting phase.

Recommendation for most users: 3 mL or 4 mL. At 3 mL (3.33 mg/mL), the doses produce clean measurements. At 4 mL (2.5 mg/mL), you get the same concentrations as the popular 5 mg + 2 mL mixing ratio.

The 15 mg vial is least common but offers maximum doses per vial. It is best for maintenance doses of 1.0 mg or higher.

Recommendation: Add 3 mL for a 5 mg/mL concentration if you are at 1.0 mg or higher. The low volume keeps injections small. Add 6 mL for 2.5 mg/mL if you need to dose at 0.5 mg or want easier measurement.

You need: the semaglutide vial (lyophilized powder), a vial of bacteriostatic water, a 3 mL syringe with a drawing needle (18-21 gauge), alcohol swabs, and an insulin syringe (U-100, 29-31 gauge) for future dosing.

Do not use sterile water for multi-dose vials. Bacteriostatic water contains 0.9% benzyl alcohol as a preservative. Without it, bacteria can grow in the vial after the first needle puncture. Read our bacteriostatic water vs sterile water guide and where to buy bacteriostatic water.

Wipe the rubber stopper of both the semaglutide vial and the bacteriostatic water vial with separate alcohol swabs. Let them air dry for 10 seconds. Do not blow on them. This step prevents bacterial contamination.

Using the 3 mL syringe, draw your target volume of bacteriostatic water. For a 5 mg vial, draw 2 mL. For a 10 mg vial, draw your chosen volume (2-5 mL). Pull back slowly and check for air bubbles. Tap the syringe barrel to float any bubbles to the top and push them out.

Insert the needle through the semaglutide vial stopper at an angle. Aim the stream of water at the glass wall, not directly onto the powder cake. Release the plunger slowly, allowing the water to trickle down the side.

Direct impact on the powder can denature the peptide. The gentler the introduction, the better the dissolution.

Remove the syringe. Hold the vial between your palms and roll it gently for 30 seconds. Then swirl in small circles. The powder should dissolve gradually over 1-5 minutes.

Shaking creates foam and can denature the peptide through mechanical stress. If you see foam, you shook too hard. Set the vial down and wait for the foam to settle before using.

The solution should be completely clear and colorless. No particles, no cloudiness, no undissolved powder. If particles remain after 5 minutes of gentle swirling, set the vial in the refrigerator for 10 minutes and swirl again.

Do not use the solution if it remains cloudy or contains visible particles after 30 minutes. This may indicate a degraded peptide.

Write on the vial or attach a label with: - Date of reconstitution - Concentration (mg/mL) - Discard date (28 days from reconstitution)

This prevents dosing errors when you have multiple vials in the refrigerator. Learn more about shelf life in our how long do reconstituted peptides last guide.

Sterile water contains no preservative. After the first needle puncture, bacteria can enter and multiply in the vial. A multi-dose vial reconstituted with sterile water becomes a contamination risk within 24 hours. Always use bacteriostatic water for multi-dose vials. See our is reconstitution solution the same as bacteriostatic water guide.

Shaking denatures proteins through mechanical stress. The foam you see after shaking is denatured semaglutide that will not work. Gentle swirling dissolves the powder without damaging the peptide chain. Patience here preserves your investment.

U-100 insulin syringes are calibrated for 100 units per mL. Using a U-40 syringe (40 units per mL) with the same markings delivers 2.5x the intended dose. A 20 IU measurement on a U-40 syringe actually draws 0.50 mL instead of 0.20 mL. This is a 250% overdose.

Always verify "U-100" on the syringe packaging. Use 29-31 gauge needles for subcutaneous injection.

Blasting water directly onto the powder cake creates foam and may denature the peptide. Aim the stream at the vial wall. Release the plunger slowly over 10-15 seconds. The water should trickle down the glass and pool at the bottom, gradually dissolving the powder.

Reconstituted semaglutide degrades significantly at room temperature. Even 24 hours at 77F reduces potency. A vial left on the counter overnight should be refrigerated immediately and used within the next few days. Repeated temperature excursions compound the damage.

A needle that has punctured skin once is no longer sterile. Reusing needles increases infection risk and causes more injection-site pain (the tip bends and dulls after the first use). Insulin needles cost pennies. Use a new one every time.