Tools · Dose math

Tirzepatide & semaglutide dosage calculator

A dose written in milligrams is not the number you draw. Turning it into units on a U-100 insulin syringe depends on the concentration of your particular vial, which is why a chart made for someone else’s vial is the wrong place to get it. This tool does that conversion transparently, for tirzepatide or semaglutide, at any dose. It is math, not a dose recommendation.

Working the other way — deciding how much bacteriostatic water to add so a small dose lands on a readable mark, and what the vial costs you per milligram — is on the reconstitution calculator.

Read before you use this

This is an educational math tool, not medical advice, and not a recommendation to microdose. Intentional GLP-1 microdosing is off-label and unproven — there are no dedicated randomized trials of sub-therapeutic GLP-1 dosing. Dosing, reconstitution, and injection technique must be directed and supervised by a licensed clinician. Never self-prescribe or adjust a dose on your own. Compounded GLP-1s are not FDA-approved products. Treat every figure below as a starting point to verify against your prescriber and the product label — confirm the vial strength, the water you added, and the target dose before drawing anything.

Medication in the vialmgTotal peptide mass labeled on the vial, e.g. 5 or 10 mg.Bacteriostatic water addedmLHow much BAC water you reconstitute the vial with, e.g. 1, 2, or 3 mL.

Desired dose

Microdoses are usually expressed in micrograms (mcg). 1 mg = 1000 mcg.

Draw on a U-100 insulin syringe

5units

to deliver a 250 mcg dose = 0.05 mL.

Concentration: 5 mg/mL; 10 mg ÷ 2 mL
Volume to inject: 0.05 mL; 0.25 mg ÷ 5 mg/mL
Doses per vial: 40; 10 mg ÷ 0.25 mg

How it is calculated. Concentration = vial (mg) ÷ bacteriostatic water (mL). Volume to inject = dose (mg) ÷ concentration. A U-100 insulin syringe holds 100 units per 1 mL, so units to draw = volume (mL) × 100. Doses per vial = vial (mg) ÷ dose (mg). Worked example: a 10 mg vial reconstituted with 2 mL = 5 mg/mL; a 250 mcg dose = 0.05 mL = 5 units, giving 40 doses per vial.

Understand the context first

A number on a syringe is the easy part. Whether low-dose GLP-1 is appropriate, safe, or worth doing at all is the part that actually matters — read these before you reconstitute anything:

This calculator is informational and not medical advice. It performs unit arithmetic only and does not account for your individual health, the specific product, injection technique, or clinical appropriateness. GLP-1 medications are available by prescription after clinician review; compounded GLP-1s are not FDA-approved, and intentional microdosing is off-label with no dedicated clinical trials. Talk to a licensed provider before acting on any number here.