Posted by Kelly_P (Verified Patient)•2026-11-06
My vial concentration is 20 mg/mL and my prescribed dose is 2.5 mg. My instructions say to draw 12.5 units. But my insulin syringes only have tic marks for 10, 20, 30... How am I supposed to eyeball 12.5? What if I accidentally draw 15 or 20?
✓ ACCEPTED CLINICAL ANSWERDr. Elena Rivera, M.D.
Kelly, do not attempt to eyeball 12.5 units on a syringe that only has marks every 10 units! That is a 1.0 mL syringe intended for high insulin doses, and guessing between marks carries a 30% margin of error.
What you need: You need 0.3 mL (30-unit) U-100 micro-syringes with half-unit graduations.
On a 0.3 mL barrel, each individual unit line is widely spaced, and there are smaller intermediate tic marks for half units (0.5, 1.0, 1.5, etc.).
- On that syringe, line 12 is clearly numbered.
- The half-unit line sits right between 12 and 13.
- Pull the black plunger tip so the top ring rests squarely on that half-unit tick mark.
If you don't have 0.3 mL syringes, message our clinical concierge through your Telehealth FX portal and we will send a complimentary pack of 30-unit precision micro-needles immediately. See the full chart: [20 mg/mL Compounded Tirzepatide Dosing Tables](/blog/tirzepatide-20mg-ml-dosing-chart-units/).