Short answer: 5 mg of tirzepatide is 100 units on a U-100 syringe at 5 mg/mL, 62.5 units at 8 mg/mL, 50 units at 10 mg/mL, 33.33 units at 15 mg/mL and 25 units at 20 mg/mL. In volume that is 1 mL at 5 mg/mL, 0.625 mL at 8 mg/mL, 0.5 mL at 10 mg/mL, 0.3333 mL at 15 mg/mL and 0.25 mL at 20 mg/mL. Compounded products are not FDA approved; check the strength on your vial label, because the units are only right for that strength.
Each row converts 5 mg at one compounded tirzepatide strength for a U-100 insulin syringe (1 mL = 100 units). Not personalized advice; confirm your dose, in mg and in units, with your prescriber or the dispensing pharmacy.
| Vial strength | Volume | U-100 units | Smallest syringe that holds it |
|---|---|---|---|
| 5 mg/mL | 1 mL | 100 units | 1 mL (100 units) |
| 8 mg/mL | 0.625 mL | 62.5 units | 1 mL (100 units) |
| 10 mg/mL | 0.5 mL | 50 units | 0.5 mL (50 units) |
| 15 mg/mL | 0.3333 mL | 33.33 units (between marks) | 0.5 mL (50 units) |
| 20 mg/mL | 0.25 mL | 25 units | 0.3 mL (30 units) |
"Between marks" means the volume does not land on a printed line, even on a 0.3 mL syringe with half-unit markings. See U-40 vs U-100 syringes and how to read the marks.
Divide the dose by the strength to get mL, then multiply by 100 for U-100 units. To check, run it backwards: units ÷ 100 × mg/mL should give back 5 mg.
5 mg ÷ 5 mg/mL = 1 mL × 100 = 100 units; check: 100 ÷ 100 × 5 = 5 mg5 mg ÷ 8 mg/mL = 0.625 mL × 100 = 62.5 units; check: 62.5 ÷ 100 × 8 = 5 mg5 mg ÷ 10 mg/mL = 0.5 mL × 100 = 50 units; check: 50 ÷ 100 × 10 = 5 mg5 mg ÷ 15 mg/mL = 0.3333 mL × 100 = 33.33 units; check: 33.33 ÷ 100 × 15 = about 5 mg5 mg ÷ 20 mg/mL = 0.25 mL × 100 = 25 units; check: 25 ÷ 100 × 20 = 5 mgIf the units on your instructions do not match this math for the strength on your vial, ask the prescriber or pharmacy before injecting.
In the Mounjaro label, 5 mg is dose step 2 of 6. The schedule has no fixed weeks for 5 mg; the label reaches it with this step: Further steps: If more glycemic control is needed, increase by 2.5 mg after at least 4 weeks on the current dose. (Mounjaro label)
In the Zepbound label, 5 mg is dose step 2 of 6. The label schedule lists it as Week 5: 5 mg once weekly; Maintenance: 5 mg, 10 mg or 15 mg once weekly for weight reduction; 10 mg or 15 mg for obstructive sleep apnea. (Zepbound label)
Compounded tirzepatide has no FDA label of its own. For reference, these are the schedules in the FDA labels that name 5 mg, with its rows highlighted.
| When | Label dose |
|---|---|
| Weeks 1 to 4 | 2.5 mg once weekly (for starting treatment only) |
| Week 5 | 5 mg once weekly |
| Further steps | Increase by 2.5 mg after at least 4 weeks on the current dose |
| Maintenance | 5 mg, 10 mg or 15 mg once weekly for weight reduction; 10 mg or 15 mg for obstructive sleep apnea |
| Maximum | 15 mg once weekly |
The label states that 2.5 mg is for starting treatment and is not an approved maintenance dose.
| When | Label dose |
|---|---|
| Start | 2.5 mg once weekly |
| Further steps | If more glycemic control is needed, increase by 2.5 mg after at least 4 weeks on the current dose |
| Maximum | 15 mg once weekly in adults |
For pediatric patients 10 years and older the Mounjaro label sets a lower maximum of 10 mg once weekly.
Full schedules: Mounjaro dosing schedule · Zepbound dosing schedule
Previous step: 2.5 mg · Next step: 7.5 mg
2.5 mg · 7.5 mg · 10 mg · 12.5 mg · 15 mg · All tirzepatide doses and strengths in one grid
Mixing a powder vial instead? The tirzepatide reconstitution guide and the free reconstitution calculator handle vials you add water to.