TL;DR: Every calculator on this site answers a per-dose question. The one people ask before ordering is a per-cycle question, and the answer is a whole number of vials. Two shapes cover almost everything. An escalating protocol — 2, 4, 8 then 12 mg weekly across sixteen weeks — totals 104 mg, which is 10.4 vials of 10 mg and therefore eleven in the shop. A flat protocol — 300 mcg of a GH secretagogue daily for twelve weeks — totals 25.2 mg, or three 10 mg vials. Apply the wastage haircut and the syringe you own moves the escalating cycle to thirteen vials and the flat one to six. All arithmetic assumes a U-100 syringe, where 1 unit = 0.01 mL.
The question the calculators don’t answer
The reconstitution calculator tells you what a dose looks like on the barrel. The cost calculator tells you what one dose costs. Neither tells you how many boxes to put in the basket, and that is the decision that happens first.
It matters because cycle totals are not intuitive. A ramp that ends at 12 mg weekly feels like a 12 mg protocol; it is really a 6.5 mg-per-week average with a tail that eats half the supply. And 300 mcg a day feels like nothing until you multiply it by 84 days.
Shape one: the escalating ramp
A common ladder: 2 mg/week, then 4, then 8, then 12, held four weeks at each rung. Sixteen weeks total. The arithmetic that matters is a running sum, not a final dose.
- Weeks 1-4 at 2 mg: 4 × 2 = 8 mg. Running total 8 mg.
- Weeks 5-8 at 4 mg: 4 × 4 = 16 mg. Running total 24 mg.
- Weeks 9-12 at 8 mg: 4 × 8 = 32 mg. Running total 56 mg.
- Weeks 13-16 at 12 mg: 4 × 12 = 48 mg. Running total 104 mg.
Note what the running total does. After twelve of the sixteen weeks — three quarters of the calendar — you have used 56 mg, just over half the cycle. The final block alone is 48 mg, 46% of the programme in four weeks.
Running total at the end of each four-week block. The last block is 46 percent of the entire cycle.
What that looks like on the syringe
Run it on a retatrutide 10mg vial reconstituted with 1.00 mL of bacteriostatic water. Concentration is 10 ÷ 1 = 10 mg/mL, so one U-100 unit carries 0.1 mg, or 100 mcg.
| Block | Weekly dose | Draw volume | U-100 units | Running total |
|---|---|---|---|---|
| Weeks 1-4 | 2 mg | 0.20 mL | 20 units | 8 mg |
| Weeks 5-8 | 4 mg | 0.40 mL | 40 units | 24 mg |
| Weeks 9-12 | 8 mg | 0.80 mL | 80 units | 56 mg |
| Weeks 13-16 | 12 mg | 1.20 mL | 120 units | 104 mg |
The 12 mg rung changes your logistics. At 10 mg/mL it is 1.20 mL — more than one U-100 barrel holds, and more than one vial holds. Each of those four doses is a complete vial (100 units, 10 mg) plus 20 units from the next. Two draws per dose, which matters below.
From milligrams to a vial count
104 mg ÷ 10 mg per vial = 10.4 vials. You cannot buy four tenths of a vial, so the nominal answer is eleven.
At the only retatrutide figure in our EU price index — €139.99 for the 10 mg vial, or €14.00 per mg — that is 11 × €139.99 = €1,539.89. The 104 mg you actually deliver would cost €1,456.00 if peptide were sold by the milligram; the €83.89 gap is whole-vial rounding.
The wastage haircut
Eleven is the label answer. A vial does not give up everything it holds — overfill, dead space, residual volume and priming losses all land on the same ledger. We are not re-deriving that here; how many doses are really in a 10mg vial works it through properly. Two numbers from it are all we need:
- Dead space per draw: roughly 3 microlitres on a fixed-needle insulin syringe, roughly 70 microlitres on a detachable-needle one.
- Residual volume: roughly 0.05 mL you will never recover from the bottom of any vial.
Now count draws. Weeks 1 to 12 are one draw each: 12. Weeks 13 to 16 are two draws per dose because 12 mg spans two vials: 8. Twenty draws total. At 10 mg/mL each microlitre of trapped solution is 0.01 mg, so:
| Line item | Fixed needle | Detachable needle |
|---|---|---|
| Peptide delivered | 104.0 mg | 104.0 mg |
| Dead space, 20 draws | 0.6 mg | 14.0 mg |
| Residual, 0.5 mg per vial | 5.5 mg | 6.5 mg |
| Total peptide required | 110.1 mg | 124.5 mg |
| Vials to buy | 11 | 13 |
| Cost at €139.99 | €1,539.89 | €1,819.87 |
Eleven vials hold 110 mg against a 110.1 mg requirement — it clears by a rounding error, and overfill is the one line in the whole calculation that works in your favour, so it covers that. Thirteen is the honest number for a Luer hub.
Two vials of difference is €279.98, decided by a syringe costing a few cents. Per delivered milligram the fixed-needle cycle runs at €14.81/mg and the detachable-needle cycle at €17.50/mg, against a listed €14.00/mg. The coste por ciclo moves 18% on a component nobody thinks about at checkout.
Shape two: the flat GH-secretagogue cadence
The opposite geometry: no ramp, just a small daily dose held for twelve weeks — the pattern most growth-hormone secretagogue work follows.
Take ipamorelin 10mg at 300 mcg once daily, reconstituted with 2.00 mL. Concentration is 10 ÷ 2 = 5 mg/mL, which is 5,000 mcg/mL, so one unit carries 50 mcg. A 300 mcg dose is 300 ÷ 50 = 6 units, or 0.06 mL — matching the grid in the ipamorelin 10mg dose chart.
Twelve weeks is 84 days, so 84 doses. 84 × 300 mcg = 25,200 mcg = 25.2 mg. One vial holds 10,000 ÷ 300 = 33 doses, and 25.2 ÷ 10 = 2.52, so the nominal answer is three vials.
Three vials at the listed €54.99 is €164.97. A vial emptied at one dose a day runs its full 33 doses in 33 days; split the 84-day cycle evenly across three vials instead and each one runs 28 days. Either way you are sitting at the top of the two-to-four-week window most people give a reconstituted secretagogue in the fridge, which is exactly why 10 mg dominates this category and 50 mg does not.
The same haircut, a much worse outcome
Here dead space stops being a rounding item and becomes the dominant cost. At 5 mg/mL, 70 microlitres of trapped solution is 0.35 mg — 350 mcg, more than the 300 mcg dose itself.
- Fixed needle: 84 draws × 0.015 mg = 1.26 mg dead space, plus 0.75 mg residual across three vials. Requirement 27.21 mg — three vials still covers it.
- Detachable needle: 84 draws × 0.35 mg = 29.4 mg of dead space alone, more than the entire delivered dose. With 25.2 mg delivered and 1.5 mg residual the requirement is 56.1 mg. Six vials.
Six vials is €329.94 — the cycle costs exactly double. Per delivered milligram that is €13.09/mg against a listed €5.50/mg.
Why the two shapes buy differently
Put them side by side and the planning advice inverts.
The escalating cycle spends most of its peptide in the last quarter, so its vial count is set by the top rung and its main leak is whole-vial rounding at doses that don’t divide into the vial — 12 mg into a 10 mg vial is the worst case here. It also splits cleanly into tranches: the first eight weeks need only 24 mg, so three vials cover half the calendar.
The flat cycle spends at a constant rate, so the vial count is a clean division and the leak is per-draw loss multiplied by a high draw count. Tranches gain nothing; the right syringe gains everything. And because reconstituted shelf life caps how long an open vial stays useful, a bigger vial is not automatically better — a 50 mg vial at 300 mcg daily would run 166 days and mostly degrade.
Retatrutide 10mg vials for the 16-week ramp; ipamorelin 10mg vials for the daily cadence.
Running your own numbers
Four lines, any protocol:
- Sum the milligrams. Doses per block × mg per dose, added up. Keep the running total visible.
- Divide by vial size, round up. That is your nominal vial count.
- Count draws, not doses. A dose that spans two vials is two draws, and every draw pays dead space.
- Add residual and re-round. Roughly 0.05 mL per vial, converted at your mg/mL.
The cost calculator does steps two to four once you have a total, returning cost per delivered dose rather than the listed Preis pro mg. The reconstitution calculator handles the mg-to-units conversion, the reconstitution chart covers standard volumes, and prices live in the price index.
Frequently Asked Questions
How many vials do I need for a 16-week escalating cycle?
On the 2, 4, 8, 12 mg ladder held four weeks per rung the cycle totals 104 mg. Against a 10 mg vial that is 10.4, so eleven on nominal arithmetic. With a detachable-needle syringe, dead space and residual push the real requirement to 124.5 mg — thirteen vials.
How do I calculate total peptide for a cycle?
Multiply doses per block by dose size, sum the blocks, divide by vial strength and round up. On the ramp above: 8 + 16 + 32 + 48 = 104 mg. Then add roughly 0.05 mL of unrecoverable residual per vial plus the dead space of every draw, converted at your mg/mL.
Does the syringe really change how many vials I buy?
More than anything else on the list. A fixed-needle insulin syringe traps about 3 microlitres per draw; a detachable-needle one traps about 70. On the escalating cycle that is two extra vials — €279.98 at €139.99 each. On the 300 mcg daily cycle it doubles the count from three to six.
How many vials for a 12-week daily peptide protocol?
At 300 mcg once daily for 84 days you deliver 25.2 mg, so three 10 mg vials nominally — €164.97 for ipamorelin. Each vial holds 33 doses, which is 33 days if you empty it or 28 days apiece if you split the cycle evenly across the three — the top edge of the reconstituted shelf life either way. On a detachable-needle syringe the same protocol needs six.
Should I buy the whole cycle up front?
For an escalating protocol you don’t have to: the first eight weeks need only 24 mg, so three vials cover half the calendar. A flat daily protocol consumes at a fixed rate, so there is no timing advantage either way — the only constraint is how long a reconstituted vial stays useful.
Why is my cost per cycle higher than vial price times vial count?
It usually isn’t — that product is your cost. What is higher than expected is cost per delivered milligram, because you paid for peptide that stayed in the hub and the vial. On the escalating cycle that moves €14.00/mg to €14.81 or €17.50 depending on syringe; on the daily cycle it moves €5.50/mg to €13.09.
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.
- Raun K, Hansen BS, Johansen NL, et al. “Ipamorelin, the first selective growth hormone secretagogue.” European Journal of Endocrinology, 1998;139(5):552-561.
- PeptiMap. “How Many Doses Are Really in a 10mg Vial?” — the overfill, dead-space and residual-volume arithmetic that the wastage haircut here is drawn from.
- PeptiMap. “EU Peptide Price Index” — build-time snapshot of listed European research-supply pricing. The €139.99, €54.99 and €44.99 figures come from that dataset, not from published literature; see the methodology for how the snapshot is taken.
This article is a research and educational reference only; the peptides discussed are not approved medicines, this is not medical advice, and it is not for human consumption.