Compounded GLP-1, in the right units.
For compounded semaglutide or tirzepatide that you reconstitute from a vial. Enter the vial strength, the BAC water you added, and the dose your provider set. For tracking & education only — it never recommends a dose.
- Manufactured pens (Ozempic, Wegovy, Mounjaro, Zepbound) are pre-filled and dialed in mg. They are not reconstituted — do not use this calculator for a pen.
- This tool is for compounded powder you mix yourself, following your provider's instructions.
Lumara is a tracking tool and does not provide medical advice, diagnosis, or treatment. This calculator computes the math from the numbers you enter; it never recommends a dose. Always follow your provider's guidance.
How to convert a compounded GLP-1 dose into units
Compounded GLP-1 medications come as a powder to reconstitute or a pre-mixed vial, drawn with an insulin syringe. Manufactured pens dial their own dose — see the warning above.
- Confirm it is a compounded vial, not a pen. A pen doses itself; only a vial is drawn with a syringe.
- Reconstitute if it is a powder. Add bacteriostatic water to set the concentration — more water makes small starting doses easier to measure.
- Enter your prescribed dose to read the exact units to draw on a U-100 syringe.
- Draw and inject as your provider instructed, and record the dose.
Worked example: a 5 mg semaglutide vial at a 0.25 mg dose
A common compounded starting setup — a 5 mg vial reconstituted with 2 mL of BAC water, at a 0.25 mg weekly dose:
- Concentration — 5 mg ÷ 2 mL = 2.5 mg/mL (2500 mcg/mL).
- Volume for your dose — 0.25 mg ÷ 2.5 mg/mL = 0.1 mL.
- Units to draw — 0.1 mL × 100 units/mL = 10 units on a U-100 syringe.
- Doses per vial — 5 mg ÷ 0.25 mg = 20 doses.
Enter your own vial strength, water, and dose above — the calculator keeps compounded and pen products separate so the two never get confused.
Sources
- U.S. Food and Drug Administration. FDA alerts health care providers, compounders and patients of dosing errors associated with compounded injectable semaglutide products. July 26, 2024.
- Lambson JE, Flegal SC, Johnson AR. Administration errors of compounded semaglutide reported to a poison control center—Case series. J Am Pharm Assoc (2003). 2023;63(5):1643-1645.
- HUMULIN R (insulin human) injection, for subcutaneous or intravenous use. Prescribing information (revised 6/2023). Eli Lilly and Company. DailyMed, U.S. National Library of Medicine; label updated June 16, 2026.
Frequently asked questions
A manufactured pen (Ozempic, Wegovy, Mounjaro, Zepbound) is pre-filled and dials its own dose — you never calculate units. A compounded vial from a pharmacy is drawn with an insulin syringe, so you convert your prescribed dose into units. This calculator is only for the compounded vial workflow.
The water only sets the concentration, not the dose. A common choice is 2 mL for a 5 mg vial (2.5 mg/mL). More water makes each unit less concentrated, which can make small starting doses easier to measure accurately. Follow the instructions from your compounding pharmacy or provider.
Yes. The math is identical for any compounded injectable — vial strength, water volume, and dose determine the units. Enter your own numbers; the tool does not assume a drug or recommend a dose.
Units refer to the U-100 insulin scale, where 100 units = 1 mL, so 10 units is 0.1 mL. Insulin syringes are marked in units, which is why compounded doses are converted to units rather than millilitres.
No. It is an educational estimation tool that does the arithmetic from the numbers you enter and shows its work. It never prescribes, diagnoses, or recommends a dose. Always follow your licensed provider’s instructions.