Free tool

Tirzepatide dosage calculator

Enter your vial size and bacteriostatic water, then the weekly dose in milligrams. The calculator works out the concentration and the units to draw on a U-100 syringe.

Reviewed for accuracy · Last reviewed July 7, 2026
Peptide amount
mg / vial
Bacteriostatic water
mL added
Target dose
mg / dose
Concentration5 mg/mL
Draw to100 units
on a 100-unit (1 mL) insulin syringe (example only)
Reflects the labeled 2.5 – 15 mg once-weekly range. Always recalculate for your own vial and water amount.

About these numbers

The example mixes a 10 mg vial with 2 mL of water for 5 mg/mL, where a 5 mg dose is 1 mL, or 100 units. Past 5 mg at this concentration the volume no longer fits one 100-unit syringe, so many people remix stronger as the dose climbs.

The approved weight-management product (Zepbound) starts at 2.5 mg once weekly and increases no sooner than every 4 weeks to a maximum of 15 mg. Independently sourced vials carry no guarantee of the purity or accuracy testing a regulated pharmacy product does.

References

  1. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1)New England Journal of Medicine · 2022 · PMID 35658024 · DOI 10.1056/NEJMoa2206038
  2. ZEPBOUND (tirzepatide) injection: DailyMed labelDailyMed (U.S. National Library of Medicine) · current · DailyMed setid 487cd7e7-434c-4925-99fa-aa80b1cc776b
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This page is an independent educational reference and is not medical advice. Talk to a doctor before starting or adjusting any compound.