Semaglutide Calculator
Also known as: Ozempic, Wegovy, Rybelsus
What is Semaglutide?
Semaglutide is a once-weekly GLP-1 receptor agonist developed by Novo Nordisk and approved as Ozempic for type 2 diabetes, Wegovy for chronic weight management, and Rybelsus as an oral tablet. Subcutaneous protocols start at 0.25 mg weekly for four weeks and titrate every four weeks (0.5 → 1 → 1.7 → 2.4 mg) to a maintenance dose. Compounded semaglutide ships as a lyophilized powder in 2 mg through 15 mg vials. At 5 mg / 2 mL the concentration is 2.5 mg/mL — a 0.25 mg starter dose draws to 10 units on a U-100 insulin syringe.
| 2 mg | lyophilized powder |
| 3 mg | lyophilized powder |
| 5 mg | lyophilized powder |
| 10 mg | lyophilized powder |
| 15 mg | lyophilized powder |
| 0.25 mg | ≈ 10 U-100 units (at 5mg / 2mL) |
| 0.5 mg | ≈ 20 U-100 units (at 5mg / 2mL) |
| 1 mg | ≈ 40 U-100 units (at 5mg / 2mL) |
| 1.7 mg | ≈ 68 U-100 units (at 5mg / 2mL) |
| 2 mg | ≈ 80 U-100 units (at 5mg / 2mL) |
| 2.4 mg | ≈ 96 U-100 units (at 5mg / 2mL) |
How it's typically prepared
Inject BAC water against the inner wall of the vial and swirl gently to dissolve. Refrigerated solutions are typically considered viable for 28–56 days depending on the compounding pharmacy.
Semaglutide Reconstitution & Dose Math
Compounded semaglutide is supplied as a lyophilized powder in 2 mg, 3 mg, 5 mg, 10 mg, or 15 mg vials. The first step is to decide the bacteriostatic-water volume, because that single choice fixes the concentration and therefore every subsequent draw. The most common compounding-pharmacy guidance is to reconstitute a 5 mg vial with 2 mL of BAC water, giving a 2.5 mg/mL concentration that places the standard Wegovy titration ladder (0.25 / 0.5 / 1 / 1.7 / 2.4 mg weekly) at convenient, easy-to-draw syringe-unit values. A 10 mg vial in 2 mL of BAC water doubles the concentration to 5 mg/mL and halves the draw volumes — useful for higher maintenance doses but harder to measure accurately at the 0.25 mg starter step.
The reconstitution arithmetic itself is two steps. First: concentration (mg/mL) = vial size (mg) ÷ BAC water (mL). Second: draw volume (mL) = dose (mg) ÷ concentration (mg/mL). A U-100 insulin syringe reads in units where 100 units equals 1 mL, so multiplying the draw volume by 100 gives the syringe reading. Worked: a 5 mg vial reconstituted in 2 mL is 2.5 mg/mL; a 0.25 mg dose is 0.25 ÷ 2.5 = 0.1 mL = 10 units. The same vial at 2.4 mg maintenance is 2.4 ÷ 2.5 = 0.96 mL = 96 units, which approaches the upper limit of a U-100 syringe.
When the maintenance dose exceeds roughly 60 units of draw volume, most protocols either switch to a more concentrated reconstitution (10 mg vial in 1.5 mL gives 6.67 mg/mL, so 2.4 mg is just 36 units) or split the weekly dose into two smaller injections to keep individual draws comfortably under 50 units. The calculator above will recompute both the mL and the syringe-unit values for any vial size and reconstitution volume, so it is straightforward to compare options before opening a vial. As with all titration decisions, the specific schedule belongs with a licensed provider.
Semaglutide Titration Schedule (Wegovy label)
Reference titration ladder from the Wegovy (semaglutide) FDA prescribing label for chronic weight management. The schedule is non-linear — step sizes vary by phase. This is informational; your provider may follow a different titration.
| Starting week | Dose | Notes |
|---|---|---|
| Week 1 | 0.25 mg/ week | — |
| Week 5 | 0.5 mg/ week | — |
| Week 9 | 1 mg/ week | — |
| Week 13 | 1.7 mg/ week | — |
| Week 17 | 2.4 mg/ week | Maintenance |
Frequently asked questions
- How do I use the semaglutide reconstitution calculator?
- Enter the vial size (the mg printed on the lyophilized vial), the volume of bacteriostatic water you will use, and the target dose. The calculator returns the concentration in mg per millilitre, the draw volume in millilitres, and the equivalent reading on a U-100 insulin syringe. Defaults are pre-set to the most common compounded preparation (5 mg / 2 mL / 0.25 mg starter dose, which works out to 10 units on a U-100 syringe). Change any input to match your specific vial.
- How many units is 0.25 mg of semaglutide?
- On a U-100 insulin syringe, 0.25 mg of semaglutide equals 10 units when the vial is reconstituted at 5 mg / 2 mL (2.5 mg/mL).
- How many units is 0.5 mg of semaglutide?
- At 5 mg / 2 mL concentration, 0.5 mg equals 20 units on a U-100 insulin syringe.
- What's the typical titration schedule?
- 0.25 mg weekly for 4 weeks → 0.5 mg for 4 weeks → 1 mg for 4 weeks → 1.7 mg for 4 weeks → 2.4 mg maintenance. Always defer to your provider's specific schedule.
- Can I split a weekly dose into two smaller doses?
- Some clinicians split the weekly dose to reduce GI side effects. This is a clinical decision and should be made with your provider — the calculator will compute either the full or split volume.
- How do I reconstitute a 5 mg semaglutide vial?
- Inject 2 mL of bacteriostatic water slowly along the inner wall of the vial — not directly onto the powder — and swirl gently to dissolve. Do not shake; the peptide is sensitive to mechanical stress. The result is a 2.5 mg/mL solution. Refrigerate at 2 to 8 °C between uses; most compounding pharmacies consider the solution viable for 28 to 56 days, with the specific window stated on the vial label.
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Other GLP-1 peptides
PeptideDose is an educational reference. It is not medical advice and does not replace consultation with a licensed healthcare provider. Doses shown in presets are derived from published protocols and product labels — they are not personal recommendations.