GLP-1 Syringe Unit Calculator
Convert your mg dose to exact syringe units — or reverse-calculate dose from units drawn.
How to Use This GLP-1 Syringe Calculator
Calculating the correct syringe units requires your prescribed dose in mg and your vial concentration in mg/mL. Formula: Volume (mL) = Dose (mg) divided by Concentration (mg/mL). For U-100 insulin syringes, multiply volume by 100 to get units. Example: 0.5mg at 1.0mg/mL = 0.5mL = 50 units on a U-100 syringe. Compounded vials at 2.5mg/mL change the calculation significantly — that same 0.5mg dose becomes only 20 units.
The reverse mode lets you enter units drawn to verify the dose you are about to inject. Use this when your provider communicates in units rather than milligrams, or as a double-check before injecting.
What Are Syringe Units?
Syringe units are the numeric markings on an insulin syringe. A U-100 syringe has 100 units per mL — each unit = 0.01mL. A U-40 syringe has 40 units per mL — each unit = 0.025mL. Most compounded GLP-1 users use U-100 insulin syringes, available without a prescription and equipped with ultra-fine 31-32 gauge needles that minimize discomfort.
Common Semaglutide Doses and Syringe Units
U-100 syringe units for semaglutide: At 0.5mg/mL — 0.25mg = 50 units, 0.5mg = 100 units. At 1.0mg/mL — 0.25mg = 25 units, 0.5mg = 50 units, 1.0mg = 100 units. At 2.5mg/mL — 0.25mg = 10 units, 0.5mg = 20 units, 1.0mg = 40 units, 1.7mg = 68 units, 2.4mg = 96 units. Always confirm from your pharmacy label.
Common Tirzepatide Doses and Syringe Units
U-100 syringe units for tirzepatide: At 2.5mg/mL — 2.5mg = 100 units. At 5.0mg/mL — 2.5mg = 50 units, 5mg = 100 units. At 10mg/mL — 2.5mg = 25 units, 5mg = 50 units, 7.5mg = 75 units, 10mg = 100 units. Higher concentration vials require drawing significantly smaller volumes.
Why Compounded GLP-1 Users Need This Calculator
Brand pens are pre-dosed. Compounded semaglutide and tirzepatide come in multi-dose vials requiring accurate drawing with a syringe. Concentrations range from 0.5 to 10+ mg/mL — the same prescribed dose of 2.5mg tirzepatide draws 100 units from a 2.5mg/mL vial but only 25 units from a 10mg/mL vial. Getting this wrong causes under- or overdosing. Always read your vial label carefully and use this calculator to verify every draw.
Frequently Asked Questions
What syringe should I use for compounded GLP-1?
U-100 insulin syringes (0.5mL or 1mL capacity) are the standard recommendation. They are inexpensive, available without prescription, and have very fine needles that minimize discomfort.
My vial says 5mg/mL — is that the concentration to enter?
Yes. Enter 5.0. If your label shows total content (e.g. 10mg in 2mL), divide: 10 divided by 2 = 5mg/mL.
Can I use a regular syringe instead of insulin syringe?
Yes. Use the mL volume result and draw to that line. The syringe type setting only matters when measuring in units rather than mL.
What if my dose falls between unit markings?
Draw to the nearest marking. Differences of 1-2 units have negligible clinical impact for most GLP-1 doses.
Does concentration affect how the drug works?
No. The prescribed dose in mg determines the clinical effect. Concentration only determines the volume you draw to deliver that dose.