GLP-1 Dose Conversion: mg → mL → Units
Once your peptide is reconstituted, every dose translates into three numbers: mg (the prescribed amount), mL (the actual liquid volume), and U100 syringe units (the marks on the barrel). Mixing them up is the #1 cause of accidental dosing errors. The Dose Volume Converter handles the conversion instantly.
1) The Conversion Math
units_U100 = mL × 100
2) Quick Conversion Chart — Most Common Concentrations
| Concentration | 0.25 mg | 0.5 mg | 1 mg | 2.5 mg | 5 mg |
|---|---|---|---|---|---|
| 1.0 mg/mL | 25 u | 50 u | 100 u | — | — |
| 2.5 mg/mL | 10 u | 20 u | 40 u | 100 u | — |
| 5.0 mg/mL | 5 u | 10 u | 20 u | 50 u | 100 u |
| 7.5 mg/mL | 3 u | 7 u | 13 u | 33 u | 67 u |
| 10 mg/mL | 2.5 u | 5 u | 10 u | 25 u | 50 u |
All values are units on a 1 mL U100 insulin syringe. Round to whole units when drawing.
Why Concentration Matters More Than You Think
A 0.5 mg dose at 2.5 mg/mL is 20 units — easy to draw accurately. The same 0.5 mg at 10 mg/mL is only 5 units, which is much harder to measure precisely on a U100 syringe (each unit is 0.01 mL). For starter doses, lower concentrations give you more drawable margin. Crank concentration up later when you're stepping into 1+ mg territory.
Common Compound & Pharmacy Concentrations
- Compound semaglutide: commonly 2.5 mg/mL (5 mg vial in 2 mL BAC water)
- Compound tirzepatide: commonly 5–10 mg/mL (higher doses → more concentrated)
- Compound retatrutide: commonly 5 mg/mL (15 mg vial in 3 mL BAC water)
- Ozempic/Wegovy pen: pre-mixed by Novo Nordisk; you don't draw — pen does it
- Mounjaro/Zepbound pen: same — pre-filled, no manual conversion needed
Convert any dose instantly
Concentration + dose → mL + units + visual fill guide.
FAQ
What's a U100 syringe?
A 1 mL insulin syringe with 100 unit marks. Each unit = 0.01 mL. Most reconstituted GLP-1 doses fit in 0.05–0.4 mL (5–40 units).
Can I draw fractional units?
Not accurately on a U100 — the marks are at integer units. If your conversion gives 2.5 units, either dilute more (lower concentration) or accept the rounding to 2 or 3.
Why does the converter want concentration in mg/mL not mg/mL/unit?
mg/mL is the standard pharmaceutical unit. The converter handles the units math automatically — you never need to think in "mg per syringe unit."
Frequently Asked Questions
What is a U100 syringe and why is it used for GLP-1?
A U100 syringe is a 1 mL insulin syringe with 100 unit marks, where each unit equals 0.01 mL. Most reconstituted GLP-1 doses fit in 0.05-0.4 mL, which is 5-40 units. The fine graduations make small-volume dosing measurable in a way milliliter-only syringes can't match.
Can I draw fractional units on a U100 syringe?
Not accurately. The marks are at integer units, so a calculation that gives 2.5 units forces a choice: dilute to a lower concentration so the dose lands on a whole number, or accept rounding to 2 or 3 units. Lower concentration is the safer option for starter doses.
What's the syringe units value for 0.5 mg semaglutide at 2.5 mg/mL?
20 units. The math is 0.5 divided by 2.5 equals 0.2 mL, then 0.2 times 100 equals 20 units on a U100 syringe. This is one of the easier conversions to draw accurately, which is why 2.5 mg/mL is a common compound semaglutide concentration.
Why does drawing higher-concentration GLP-1 increase dosing error risk?
At 10 mg/mL, a 0.5 mg dose is only 5 units, leaving little margin for error on a U100 syringe. Dropping concentration to 2.5 mg/mL turns the same dose into 20 units, far easier to measure. Use lower concentration for starter doses, then concentrate up at higher doses.
Do you need to convert doses if you're using an Ozempic or Mounjaro pen?
No. Pens like Ozempic, Wegovy, Mounjaro, and Zepbound are pre-mixed and pre-calibrated by the manufacturer; you dial the dose and the pen delivers the correct volume. Conversion math only applies to compound peptides reconstituted from a vial of lyophilized powder.