Vial duration

Retatrutide vial duration calculator

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

iPhone · Free to download

Last updated: May 13, 2026

Vial (mg)

Dose (mg)

Doses / week

Total doses

Lasts

5.0 weeks

Retatrutide weeks-of-supply at common cadences

How long one 10 mg Retatrutide vial covers at a 2 mg per dose, for three weekly cadences. Total doses per vial: 5.

Doses per week	Total doses per vial	Weeks of supply
1	5	5.0
1	5	5.0
2	5	2.5

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 Retatrutide vial lasts, the long version

Total doses in the vial: floor(10 ÷ 2) = 5. The floor matters — a partial dose at the bottom doesn't count.
Cadence: 1 dose per week for Retatrutide at this example step.
Math weeks-of-supply: 5 ÷ 1 = 5.0 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 Retatrutide

Math says one 10 mg Retatrutide vial covers 5.0 weeks at 2 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

Retatrutide next to Liraglutide

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

	Retatrutide	Liraglutide
Vial	10 mg	6 mg
Cadence	1/wk	7/wk
Weeks of supply	5.0	0.7

Want the full breakdown? Liraglutide reference →

Retatrutide is an experimental once-a-week injection people are tracking for weight loss and blood-sugar effects. It's the first triple agonist — it hits GLP-1, GIP, and glucagon receptors together, which appears to amplify both appetite suppression and energy expenditure. In a Phase 2 trial, adults with obesity lost about 24.2% of body weight at 48 weeks on the highest dose. It is still investigational and not approved. This page covers the reconstitution math and weekly logging cadence.

Planning Retatrutide vials in real life

Retatrutide titration is steeper than semaglutide or tirzepatide because the trial doses run higher. A 10 mg vial covers 5 weeks at 2 mg but only 1.25 weeks at 8 mg. If you're following the trial's titration arc — 2 mg for 4 weeks, then 4 mg, then 8 mg — your vial cadence shifts from monthly to weekly inside one quarter. That's the single most common refill mistake: planning around the starter step.

Stability is the same 4-6 week refrigerated window as other GLP-1s. At 4 mg+ doses you'll always finish inside the window, so stability is rarely the binding constraint — vial size is. Many retatrutide users move from 10 mg vials to larger vials at the 4 mg step specifically to keep refill cadence on a monthly rhythm.

Storage and shelf life for Retatrutide

Lyophilized retatrutide powder is typically stored refrigerated until reconstitution. Once reconstituted, the in-use vial is generally kept refrigerated and used within several weeks. Marking the reconstitution date directly on the vial is the simplest way to avoid using a long-opened vial past its useful life.

How the Retatrutide vial duration calculator works

A 10 mg retatrutide vial covers 5 weeks at the 2 mg trial step, 2.5 weeks at 4 mg, and just over 1 week at 8 mg. Like tirzepatide, retatrutide moves through a vial fast — start refill planning at the 2-week mark of a new 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 Retatrutide, a 2 mg dose, and 1 dose per week, the vial covers 5 doses, or about 5.0 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 Retatrutide vial-planning mistakes

Reusing a unit count from a previous vial without re-checking the new vial's diluent volume.
Not writing the reconstitution date on the vial itself — the in-use window is long enough that an unmarked vial becomes ambiguous.

Frequently asked questions about Retatrutide vial duration

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

It floors total doses (vial mg ÷ dose mg) then divides by doses per week. For this Retatrutide example — a 10 mg vial, 2 mg per dose, 1 dose/week — that's floor(10 ÷ 2) ÷ 1 = about 5.0 weeks. Flooring matters: a partial dose left in the vial doesn't count. Retatrutide titration eats vials fastest of any GLP-1 — keep 2 vials on hand once you pass the 4 mg step.

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

Whichever runs out first. Math says Retatrutide 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. Retatrutide titration eats vials fastest of any GLP-1 — keep 2 vials on hand once you pass the 4 mg step.

Does titrating the Retatrutide 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. Retatrutide titration eats vials fastest of any GLP-1 — keep 2 vials on hand once you pass the 4 mg step.

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

Drop the doses-per-week field. With 1 dose/week the example vial lasts about 5.0 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. Retatrutide titration eats vials fastest of any GLP-1 — keep 2 vials on hand once you pass the 4 mg step.

Related on Peptide Pilot

Track Retatrutide vials automatically

iPhone · Free · No credit card