Vial duration

Tirzepatide vial duration calculator

Estimate how many weeks one 10 mg Tirzepatide vial covers at your dose and weekly cadence.

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Last updated: May 13, 2026

Vial (mg)

Dose (mg)

Doses / week

Total doses

Lasts

4.0 weeks

Tirzepatide weeks-of-supply at common cadences

How long one 10 mg Tirzepatide vial covers at a 2.5 mg per dose, for three weekly cadences. Total doses per vial: 4.

Doses per week	Total doses per vial	Weeks of supply
1	4	4.0
1	4	4.0
2	4	2.0

Math weeks-of-supply assumes every dose draws cleanly. Stability typically caps a reconstituted vial at 4–6 weeks of refrigerated use regardless of how much liquid remains.

Worked example

How long one Tirzepatide vial lasts, the long version

Total doses in the vial: floor(10 ÷ 2.5) = 4. The floor matters — a partial dose at the bottom doesn't count.
Cadence: 1 dose per week for Tirzepatide at this example step.
Math weeks-of-supply: 4 ÷ 1 = 4.0 weeks of liquid in the vial.
Stability ceiling: most reconstituted peptides are typically used within 4–6 weeks of refrigerated storage. Whichever number is smaller is the one that binds your refill date.
Doubling the dose roughly halves both numbers — and titration usually closes the gap between "math weeks" and "stability weeks" without you noticing.

Scenarios people actually run into

Three things that come up logging Tirzepatide

Math says one 10 mg Tirzepatide vial covers 4.0 weeks at 2.5 mg per dose. Stability typically caps a reconstituted vial at 4–6 weeks. Whichever number is smaller is the date on your refill calendar.
Titration up doubles the dose and halves the vial. A 12-week-on-paper vial becomes a 6-week vial the day you step up — order the next vial the same day you take the step.
Shipping windows are the silent third constraint. If your supplier runs 1–3 weeks, the refill order has to leave at least that long before "math weeks" or "stability weeks," whichever is binding.

Same-category neighbor

Tirzepatide next to Semaglutide

Both sit in the GLP-1 bucket — here's the vial duration math side by side on each one's example vial.

	Tirzepatide	Semaglutide
Vial	10 mg	5 mg
Cadence	1/wk	1/wk
Weeks of supply	4.0	20.0

Want the full breakdown? Semaglutide reference →

Tirzepatide is a once-a-week injection people use to lose weight and improve blood sugar control. It hits two gut-hormone receptors at once — GLP-1 and GIP — which is why it tends to drive larger appetite and weight changes than single-receptor drugs. In the SURMOUNT-1 trial, participants without diabetes lost roughly 20.9% of body weight over 72 weeks on the highest dose. This page covers reconstitution math and weekly dose logging.

Planning Tirzepatide vials in real life

Tirzepatide vials run through faster than any other GLP-1 because the doses are larger. The math is simple: vial mg ÷ dose mg = number of weekly draws. A 10 mg vial covers 4 doses at 2.5 mg, 2 at 5 mg, and 1.3 at 7.5 mg — meaning at 7.5 mg you'll have one full draw plus a partial that doesn't count. Once you pass the 5 mg titration step, weekly refill planning becomes monthly refill planning.

The 4-6 week stability ceiling rarely bites tirzepatide users, because most vials empty before that window closes. The bigger refill question is shipping. If you titrate up to 10 mg or 15 mg, every vial is a 1-2 week supply — order the next one the same day you open the current one, and a missed delivery doesn't break the cadence.

Storage and shelf life for Tirzepatide

Lyophilized tirzepatide powder is typically stored refrigerated until reconstitution. The in-use reconstituted vial is generally kept refrigerated and used within several weeks. As with all peptides, writing the reconstitution date directly on the vial avoids the common case of finding an unmarked vial in the refrigerator and not knowing whether it is still in its useful window.

How the Tirzepatide vial duration calculator works

A 10 mg tirzepatide vial gives you 4 weekly doses at the 2.5 mg starter step. That drops to 2 weeks at 5 mg and just over 1 week at 10 mg. Tirzepatide vials empty quickly compared to semaglutide — refill planning starts at week 2 of a fresh vial.

The formula is two divisions. Total doses per vial equals vial mg divided by dose mg, rounded down. Weeks of supply equals total doses divided by doses per week. With a 10 mg vial of Tirzepatide, a 2.5 mg dose, and 1 dose per week, the vial covers 4 doses, or about 4.0 weeks of supply.

The three inputs that move the answer: vial mg (set when you bought the vial), dose mg (set by your protocol step), and doses-per-week (set by the peptide's half-life). Once a vial is reconstituted it also has a stability ceiling — most lyophilized peptides reconstituted in BAC water are typically used within four to six weeks of refrigerated storage, so a vial that mathematically lasts twelve weeks may not last twelve weeks in practice.

Common Tirzepatide vial-planning mistakes

Underestimating doses-per-vial on a high-strength vial because the vial looks small even though it contains many weeks of supply.
Reusing the unit count from a previous vial after switching to a new vial that was reconstituted with a different diluent volume.
Letting reconstituted tirzepatide sit at room temperature on travel days when a small cooler bag would have kept it refrigerated.

Frequently asked questions about Tirzepatide vial duration

How does the Tirzepatide vial duration calculator estimate weeks of supply?

It floors total doses (vial mg ÷ dose mg) then divides by doses per week. For this Tirzepatide example — a 10 mg vial, 2.5 mg per dose, 1 dose/week — that's floor(10 ÷ 2.5) ÷ 1 = about 4.0 weeks. Flooring matters: a partial dose left in the vial doesn't count. At 5 mg+ doses, a 10 mg vial finishes inside the stability window naturally — no extra planning needed.

Should I plan refills around the math, or around stability?

Whichever runs out first. Math says Tirzepatide at the example dose lasts the calendar weeks shown above. Stability says most reconstituted peptides are typically used within 4–6 weeks of refrigerated storage regardless of how much liquid is left. If the math says 12 weeks but stability caps at 5, plan around 5 — and reconstitute the next vial with less water so you finish it in the stability window. At 5 mg+ doses, a 10 mg vial finishes inside the stability window naturally — no extra planning needed.

Does titrating the Tirzepatide dose up shorten vial life?

Yes, often dramatically. Doubling the dose halves the doses-per-vial. The calculator shows real-time how a step-up changes the weeks-of-supply line, so you can re-time refill orders before a titration event rather than discovering the gap mid-protocol. At 5 mg+ doses, a 10 mg vial finishes inside the stability window naturally — no extra planning needed.

What if I take Tirzepatide less often than the default cadence here?

Drop the doses-per-week field. With 1 dose/week the example vial lasts about 4.0 weeks; halving the cadence roughly doubles that, but you'll hit the stability ceiling first. A vial that mathematically covers 16 weeks rarely covers 16 weeks in practice. At 5 mg+ doses, a 10 mg vial finishes inside the stability window naturally — no extra planning needed.

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