Tirzepatide units, by the container you actually hold

Volumes and strengths are read from the Mounjaro and Zepbound prescribing information (Dosage Forms and Strengths). Only 2.5 mg and above are labeled doses.

What each container is

Pre-filled single-dose pen0.5 mL/dose

One pen, one pre-set dose, no dial. There is nothing to measure or adjust.

Single-dose vial0.5 mL/dose

One dose in 0.5 mL, intended to be drawn and given in full.

Multi-dose vial0.6 mL/dose

Holds four full weekly doses at a stated concentration — the only branded presentation where you draw your own volume.

Single-patient-use KwikPen0.6 mL/dose

Holds four doses of ONE fixed strength. It repeats the same dose; it is not a dial-a-dose menu.

Common questions

Why does the same tirzepatide dose read a different number of units?

Because the volume per dose is not the same across presentations. Mounjaro and Zepbound both list four presentations in their prescribing information: pre-filled single-dose pens, single-dose vials, multi-dose vials and single-patient-use KwikPens. The single-dose presentations deliver each dose in 0.5 mL; the multi-dose vial and the KwikPen deliver it in 0.6 mL. Same milligrams in a different volume means a different concentration, and therefore a different mark on a syringe. A 2.5 mg dose is 5 mg/mL and 50 units from a single-dose container, and 4.17 mg/mL and 60 units from a four-dose one.

Can I draw a partial dose from any of these?

Only one of the four is a container you draw from at all. The pre-filled single-dose pen is one pre-set dose with no dial. The single-dose vial holds one dose intended to be given in full. The single-patient-use KwikPen holds four doses of a single fixed strength — it repeats the same dose rather than offering a menu. Only the multi-dose vial holds four full weekly doses at a stated concentration from which a volume is drawn, and even that exists to deliver full doses rather than to be divided into smaller ones.

Is there an approved tirzepatide microdose?

No. The labeled ladder starts at 2.5 mg once weekly, and that rung is a tolerance-building step rather than a maintenance dose. Any dose below it sits outside what any label defines and outside what any randomized trial has tested. This tool does arithmetic; it does not indicate that a sub-label dose is safe or effective.

Does this work for compounded tirzepatide?

The arithmetic does, but the inputs do not come from this tool. Compounded product is not required to match Lilly's concentrations, so you must read the milligrams-per-milliliter figure off your own vial and recompute on every refill. FDA has also documented compounded tirzepatide with false label information, including labels naming compounding pharmacies that do not exist — so establishing who compounded the product comes before any calculation.

The full comparison, sourced to both labels, is in how many units is a microdose of tirzepatide? If you are working from a compounded vial instead, start with how to reconstitute and measure a compounded GLP-1 microdose, and read the tirzepatide microdosing procedure for why establishing who compounded it comes before any arithmetic. Other calculators are in the full tool set.