Compounded Semaglutide and Tirzepatide Dosage Chart: mg to Units
On a U-100 insulin syringe, 100 units is 1 mL, so units = dose in mg ÷ vial strength in mg/mL × 100. A 0.25 mg semaglutide dose is 10 units from a 2.5 mg/mL vial but 5 units from a 5 mg/mL vial; a 2.5 mg tirzepatide dose is 25 units from a 10 mg/mL vial. The same dose is a different number of units in every strength, which is why the FDA has reported patients taking 5 to 20 times their intended dose. Use this chart only to double-check the units on your pharmacy label.
Quick answer
- Formula: units = dose (mg) ÷ concentration (mg/mL) × 100, for a U-100 syringe where 1 mL = 100 units.
- Semaglutide at 2.5 mg/mL: 0.25 mg = 10 units, 0.5 mg = 20, 1 mg = 40, 1.7 mg = 68, 2.4 mg = 96.
- Tirzepatide at 10 mg/mL: 2.5 mg = 25 units, 5 mg = 50, 7.5 mg = 75, 10 mg = 100; 12.5 and 15 mg need more than one 1 mL syringe.
- Doses under 2 units are hard to measure on a 1 mL syringe, so a weaker vial or a smaller syringe is safer; your pharmacist decides.
Semaglutide: mg to units
| Dose | 2.5 mg/mL vial | 5 mg/mL vial | 10 mg/mL vial | 20 mg/mL vial |
|---|---|---|---|---|
| 0.25 mg | 10 units (0.1 mL) | 5 units (0.05 mL) | 2.5 units (0.025 mL) | 1.25 units (0.0125 mL): too small to measure reliably |
| 0.5 mg | 20 units (0.2 mL) | 10 units (0.1 mL) | 5 units (0.05 mL) | 2.5 units (0.025 mL) |
| 1 mg | 40 units (0.4 mL) | 20 units (0.2 mL) | 10 units (0.1 mL) | 5 units (0.05 mL) |
| 1.7 mg | 68 units (0.68 mL) | 34 units (0.34 mL) | 17 units (0.17 mL) | 8.5 units (0.085 mL) |
| 2.4 mg | 96 units (0.96 mL) | 48 units (0.48 mL) | 24 units (0.24 mL) | 12 units (0.12 mL) |
Tirzepatide: mg to units
| Dose | 2.5 mg/mL vial | 5 mg/mL vial | 10 mg/mL vial | 20 mg/mL vial |
|---|---|---|---|---|
| 2.5 mg | 100 units (1 mL) | 50 units (0.5 mL) | 25 units (0.25 mL) | 12.5 units (0.125 mL) |
| 5 mg | 200 units (2 mL): more than one 1 mL syringe | 100 units (1 mL) | 50 units (0.5 mL) | 25 units (0.25 mL) |
| 7.5 mg | 300 units (3 mL): more than one 1 mL syringe | 150 units (1.5 mL): more than one 1 mL syringe | 75 units (0.75 mL) | 37.5 units (0.375 mL) |
| 10 mg | 400 units (4 mL): more than one 1 mL syringe | 200 units (2 mL): more than one 1 mL syringe | 100 units (1 mL) | 50 units (0.5 mL) |
| 12.5 mg | 500 units (5 mL): more than one 1 mL syringe | 250 units (2.5 mL): more than one 1 mL syringe | 125 units (1.25 mL): more than one 1 mL syringe | 62.5 units (0.625 mL) |
| 15 mg | 600 units (6 mL): more than one 1 mL syringe | 300 units (3 mL): more than one 1 mL syringe | 150 units (1.5 mL): more than one 1 mL syringe | 75 units (0.75 mL) |
How to read the chart
- Find your vial strength on the pharmacy label (mg per mL), not the total mg in the vial. A 2 mL vial with 10 mg in it is 5 mg/mL.
- Find your prescribed dose in mg. The doses in the chart are the steps on the FDA-approved Wegovy and Zepbound labels; compounded prescriptions may use other doses.
- The units in the cell are the mark on a U-100 insulin syringe. U-40 and other syringes read differently; do not use them with this chart.
- For any other vial strength or dose, the dose-to-units calculator does the same math and shows the syringe.
What the FDA has seen go wrong
- The FDA has received adverse-event reports, some requiring hospitalization, after dosing errors with compounded semaglutide in multi-dose vials. Most patients drew up more than prescribed and took 5 to 20 times the intended dose.
- Confusion between milliliters, milligrams and “units” contributed: some patients told to draw 5 units (0.05 mL) on a 1 mL syringe drew 50 units instead.
- Prescribers also miscalculated: one intended 0.25 mg (5 units) but prescribed 25 units; another prescribed 20 units instead of 2.
- The FDA recommends discarding a multi-dose vial 28 days after first use, using a new sterile needle and syringe for each dose, and not using a GLP-1 that arrives warm.
FAQ
How many units is 0.25 mg of compounded semaglutide?
It depends on the vial strength. On a U-100 syringe, 0.25 mg is 10 units from a 2.5 mg/mL vial, 5 units from a 5 mg/mL vial and 2.5 units from a 10 mg/mL vial. Check the units printed on your pharmacy label.
How many units is 2.5 mg of compounded tirzepatide?
On a U-100 syringe, 2.5 mg of tirzepatide is 100 units from a 2.5 mg/mL vial, 50 units from a 5 mg/mL vial, 25 units from a 10 mg/mL vial and 12.5 units from a 20 mg/mL vial.
How do I convert mg to units for a GLP-1 vial?
Divide the dose in mg by the vial concentration in mg/mL, then multiply by 100. That gives units on a U-100 insulin syringe, where 1 mL equals 100 units. Example: 5 mg ÷ 10 mg/mL × 100 = 50 units.
Why do compounded GLP-1 doses come in units?
Compounded semaglutide and tirzepatide are sold in multi-dose vials of different strengths, so pharmacies translate the mg dose into syringe units. The FDA warns this has led to overdoses when people confused units, mL and mg.
Do Wegovy or Zepbound pens need a units chart?
No. FDA-approved Wegovy, Ozempic and Zepbound pens deliver a set dose in milligrams. Unit conversions apply to compounded multi-dose vials (and Zepbound vials are single-dose, drawn whole).
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