TL;DR: Cost per mg falls hard as you climb the vial ladder — but for retatrutide specifically, our EU price index currently lists one size: a 10 mg vial at €139.99, or €14.00 per mg. The 5, 15, 20, 30 and 50 mg sizes have no listed price in our dataset, so we won’t invent one. What we can do is show the arithmetic: doses per vial at each titration rung, where whole-vial rounding quietly inflates your real cost per mg, and how the same ladder behaves on sibling molecules that do have multiple sizes listed. Then hand it to the cost calculator.
The one number our index actually has
Every cost-per-mg claim on this site comes from the same place: a build-time snapshot of listed EU research-supply prices, published as the EU peptide price index. For retatrutide, that snapshot contains a single row.
That is the honest starting position. The 5 mg, 15 mg, 20 mg, 30 mg and 50 mg vials exist as catalogue entries — the retatrutide 5mg page and retatrutide 10mg page both resolve — but only the 10 mg carries a price we can stand behind. Anyone quoting you a firm precio por mg for a 50 mg retatrutide vial is extrapolating, and should say so.
What €14.00/mg buys you at each titration rung
The TRIUMPH phase 3 programme runs retatrutide at 2, 4, 6, 9 and 12 mg weekly, escalating roughly every four weeks. Because cost per mg is flat within a vial size, weekly spend is just a multiplication — and doses per vial is just division.
From a single 10 mg vial:
- 2 mg/week → 10 ÷ 2 = 5 doses, five weeks per vial, €28.00/week
- 4 mg/week → 10 ÷ 4 = 2.5 doses, €56.00/week
- 6 mg/week → 10 ÷ 6 = 1.67 doses, €84.00/week
- 9 mg/week → 10 ÷ 9 = 1.11 doses, €126.00/week
- 12 mg/week → 10 ÷ 12 = 0.83 doses, €168.00/week
Worked example for a full 24-week ramp on the TRIUMPH ladder: four weeks at 2 mg (8 mg), four at 4 mg (16 mg), four at 6 mg (24 mg), four at 9 mg (36 mg), then eight weeks at 12 mg (96 mg). Total 180 mg. At €14.00/mg that is €2,520.00 — and because 180 divides cleanly by 10, it is exactly 18 vials at €139.99 = €2,519.82. No rounding loss. That tidiness is luck, not design, as the next section shows.
Whole-vial rounding is where cost per mg actually lives
Listed cost per mg assumes you use every milligram. You often don’t — and the gap is bigger than most people expect.
Take a steady 6 mg weekly dose. One 10 mg vial yields one full dose plus a 4 mg remainder. If that remainder never gets used, your effective cost per delivered mg is 139.99 ÷ 6 = €23.33/mg — a 67% premium over the €14.00 headline. You stranded €56.00 of peptide in a vial you already paid for.
Carry the remainder across consecutive weeks instead and the picture inverts: five vials give 50 mg, which is eight 6 mg doses (48 mg) with 2 mg left over. That is 5 × €139.99 ÷ 48 = €14.58/mg — within 4% of the listed rate. Same vials, same price, different arithmetic.
The ladder discount, measured on molecules that have one
Retatrutide has no second size to compare against, but four of its close relatives in the same price snapshot do. Here is the real per-mg drop when the vial doubles from 5 mg to 10 mg:
- Tirzepatide €13.00 → €7.50/mg (-42.3%)
- Semaglutide €12.00 → €7.50/mg (-37.5%)
- Survodutide €15.00 → €10.90/mg (-27.3%)
- Mazdutide €13.00 → €9.90/mg (-23.8%)
Mean drop on a single doubling: about -33%. Tirzepatide is the only compound in the index with a third rung, and it keeps falling.
Listed EU price-index figures: 5mg at EUR 64.99, 10mg at EUR 74.99, 30mg at EUR 149.99. The only three-rung ladder in our dataset.
From 5 mg to 30 mg, tirzepatide’s per-mg cost falls 61.5%. Six 5 mg vials cost €389.94 for the same 30 mg that one 30 mg vial delivers for €149.99 — a €239.95 difference. Even against three 10 mg vials (€224.97) the single large vial saves €74.98. That is the shape a Preis pro mg curve takes when a supplier actually stocks the ladder.
Where the break-even sits
The break-even is not a price ratio — it is a usage threshold. A larger vial wins the moment your total programme need crosses what one smaller vial holds.
Tirzepatide again, since it has real numbers on both rungs. If you need 5 mg or less in total, the 5 mg vial is cheaper in absolute terms: €64.99 versus €74.99. Cross into 6 mg and you now need two 5 mg vials at €129.98, against one 10 mg vial at €74.99. The break-even lands exactly at the top of the smaller vial, and past it the larger size wins by 42%.
Apply the same logic to retatrutide’s titration and the threshold arrives almost immediately. A 12 mg weekly dose exceeds a single 10 mg vial on week one. At 9 mg weekly you clear 10 mg by week two. Only the 2 mg starting rung keeps you inside one vial for a meaningful stretch — five weeks.
Hand the numbers to the calculator
None of this is worth re-deriving by hand every time a dose changes. Two tools do it:
- The cost calculator takes vial price, vial size and weekly dose and returns cost per mg, cost per dose, doses per vial and cost per week — including the whole-vial rounding effect described above.
- The retatrutide calculator handles the other half: reconstitution volume, mg/mL, and units on the syringe for whichever rung you’re on.
If the reconstitution math itself is what you’re after rather than the prix par mg, the retatrutide dosing calculator guide walks the mg-to-units conversion step by step. And the full cross-compound table lives in the price index.
Frequently Asked Questions
How much does retatrutide cost per mg?
In our EU price index snapshot, the only listed retatrutide vial is 10 mg at €139.99, which works out to €14.00 per mg. No other vial size in the retatrutide catalogue carries a price in our dataset, so a per-mg figure for 15, 20, 30 or 50 mg vials would be guesswork rather than data.
Is a bigger retatrutide vial cheaper per mg?
Almost certainly, based on every sibling molecule we can measure — doubling a GLP-1 vial from 5 mg to 10 mg cuts cost per mg by roughly a third on average, and tirzepatide’s 30 mg vial is 61.5% cheaper per mg than its 5 mg. But we have no second retatrutide price to confirm it directly.
How many doses are in a 10mg retatrutide vial?
It depends entirely on your rung: five doses at 2 mg, two and a half at 4 mg, roughly 1.7 at 6 mg, and less than one full dose at 12 mg. The cost calculator returns doses per vial and cost per week for any combination you enter.
Why is my real cost per mg higher than the listed price?
Whole-vial rounding. If your dose doesn’t divide evenly into the vial and you discard the remainder, you pay for milligrams you never use. At 6 mg weekly from a 10 mg vial, discarding pushes effective cost from €14.00 to €23.33 per mg — a 67% premium on nothing.
What’s the cheapest vial size for a full retatrutide titration?
A 24-week TRIUMPH-style ramp totals about 180 mg. At the only listed size that is 18 vials and roughly €2,520. A larger vial would almost certainly beat that on a per-mg basis, but since no larger retatrutide size is priced in our index, we can’t put a number on the saving.
Where do these prices come from?
They are a build-time snapshot of listed EU research-supply prices, compiled into the price index. They are catalogue figures, not literature values, and they move — see our methodology for how the snapshot is taken and what it does and doesn’t cover.
References
- Jastreboff AM, Kaplan LM, Frías JP, et al. “Triple–Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial.” New England Journal of Medicine, 2023;389:514-526. doi:10.1056/NEJMoa2301972.
- Eli Lilly and Company. “Lilly’s triple agonist, retatrutide, delivered powerful weight loss in pivotal Phase 3 obesity trial.” Investor news release, 21 May 2026 — TRIUMPH-1 topline, doses 4 mg, 9 mg and 12 mg over 80 weeks.
- Coskun T, Urva S, Roell WC, et al. “LY3437943, a novel triple glucagon, GIP, and GLP-1 receptor agonist for glycemic control and weight loss: preclinical and Phase 1 studies.” Cell Metabolism, 2022;34(9):1234-1247.
- Sanyal AJ, Kaplan LM, Frías JP, et al. “Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver disease: a randomized phase 2a trial.” Nature Medicine, 2024;30:2037-2048.
- PeptiMap. “EU Peptide Price Index” — build-time snapshot of listed European research-supply pricing across 50+ compounds. Pricing figures in this article are drawn from that dataset, not from published literature.
This article is a research and educational reference only; retatrutide is not an approved medicine, this is not medical advice, and it is not for human consumption.