Semaglutide Dosing Calculator & Reconstitution Guide
A long-acting GLP-1 receptor agonist used for glycemic control and weight management.
To calculate a semaglutide dose, divide your vial strength by the bacteriostatic water you added to get a mg/mL concentration, then divide your target dose by that concentration. Example: a 5 mg vial reconstituted with 2 mL water is 2.5 mg/mL, so a 0.25 mg dose is 0.1 mL — 10 units on a U-100 insulin syringe.
- Category
- GLP-1 receptor agonist
- Dose unit
- mg
- Commonly reported range
- 0.25-2.4 mg
- Typical concentration
- 2.5 mg/mL
Use the Keel dose calculator to enter your numbers and see the exact units to draw, or use the built-in calculator further down this page.
What is Semaglutide?
Semaglutide is a GLP-1 receptor agonist with a half-life of roughly 7 days, allowing once-weekly dosing. Therapeutic protocols typically begin at a low dose and titrate upward over several weeks to limit gastrointestinal side effects. Reconstituted lyophilized semaglutide is dosed in milligrams; precise reconstitution math is essential because the per-dose volume is very small. Also known as Ozempic, Wegovy, Rybelsus, sema.
How many units is each Semaglutide dose?
| Dose | Volume to draw | Units (U-100) |
|---|---|---|
| 0.25 mg | 0.1 mL | 10 units |
| 0.5 mg | 0.2 mL | 20 units |
| 1 mg | 0.4 mL | 40 units |
| 1.7 mg | 0.68 mL | 68 units |
| 2.4 mg | 0.96 mL | 96 units |
Based on a 5 mg vial reconstituted with 2 mL of bacteriostatic water (2.5 mg/mL) and a U-100 insulin syringe. The dose amounts shown are commonly reported by the community and in anecdotal research, not recommendations or medical advice; only the reconstitution math (volume and units) is calculated for you.
How to calculate a Semaglutide dose
- 1
Choose your vial and water
Select your Semaglutide vial size (for example 5 mg) and the volume of bacteriostatic water you will add (for example 2 mL).
- 2
Find the concentration
Divide vial milligrams by water volume. 5 mg in 2 mL gives 2.5 mg/mL.
- 3
Calculate the draw
Divide your target dose by the concentration to get the volume in mL, then multiply by 100 to get units on a U-100 insulin syringe.
- 4
Verify on the syringe
Use the Keel calculator to see the exact draw rendered on a to-scale syringe, with a warning if the dose exceeds the syringe capacity.
Semaglutide dosing FAQ
How many units of semaglutide is 0.25 mg?
At a concentration of 2.5 mg/mL (a 5 mg vial in 2 mL of bacteriostatic water), 0.25 mg equals 0.1 mL, which is 10 units on a U-100 insulin syringe. The exact unit count depends on your reconstitution ratio, so always recalculate when you change vial size or water volume.
How much bacteriostatic water do I add to a 5 mg semaglutide vial?
Most users add 1-3 mL. Adding 2 mL gives 2.5 mg/mL, a convenient ratio where 0.25 mg is 10 units. Less water makes a more concentrated solution and a smaller draw; more water makes the draw larger and easier to measure.
Is this the same dosing as Ozempic or Wegovy?
Semaglutide is the active ingredient in Ozempic, Wegovy, and Rybelsus. The milligram targets are similar, but branded pens are pre-filled and dial-a-dose. This calculator is for reconstituting and drawing semaglutide from a vial with an insulin syringe.
What semaglutide titration schedule do people report?
Community and anecdotal reports commonly describe starting around 0.25 mg weekly for 4 weeks, then stepping up (for example 0.5 mg, 1 mg, 1.7 mg, 2.4 mg) every few weeks. These are figures people report, not a recommendation from Keel; recalculate your draw at each step and consult a licensed healthcare professional.
Why is the injection volume so small?
Semaglutide is potent and dosed in fractions of a milligram, so even a concentrated vial produces a draw of only a few units. A 0.3 mL (30-unit) insulin syringe gives the most precise measurement for these small volumes.
Semaglutide side effects
See the adverse effects most commonly reported for Semaglutide and its class, and log your own experience over time, in the Peptide & GLP-1 Side Effects reference & tracker.