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Retatrutide Calculator

A vial strength and a water volume give a concentration. A concentration and a syringe give units. Worked for the vial sizes tracked across vendors — not generic examples.

Last reviewed: September 20, 2026

Vial strength and water volume give a concentration; a dose then gives the unit mark it corresponds to.

Retatrutide

Vial sizes vendors carry — tap to fill:

How much bac water?
Syringe barrel

For research purposes only. Always verify calculations independently before use.

On this page
  1. 1.What reconstitution is
  2. 2.What sizes does retatrutide come in?
  3. 3.The arithmetic, worked
  4. 4.Units to draw, by vial size and dose
  5. 5.What one vial comes to
  6. 6.What changes the answer
  7. 7.How long does reconstituted retatrutide last?
  8. 8.FAQ
  9. 9.References

What reconstitution is

Retatrutide, like other research peptides, ships from vendors as a lyophilized (freeze-dried) powder sealed in a vial. Reconstitution is the act of dissolving that powder in a liquid — typically bacteriostatic water — which turns a fixed mass of peptide (the vial’s labeled mg content) into a solution with a defined concentration, measurable in volume with a syringe. The mass doesn’t change; only how that mass is distributed through a volume of liquid changes.

Retatrutide is investigational — not an FDA-approved product — so there is no manufacturer instruction for reconstituting it. The math below is generic pharmaceutical arithmetic (concentration = mass ÷ volume), the same relationship that governs any lyophilized compound dissolved in a diluent, applied to the vial sizes retatrutide is actually sold in. For the compound’s mechanism (a triple GIP/GLP-1/glucagon receptor agonist) and trial evidence, see the retatrutide profile.

What sizes does retatrutide come in?

Eleven sizes, from 5 mg to 60 mg, are each carried by three or more of the vendors tracked here — the sizes with a real, multi-vendor market rather than one vendor’s own catalog choice. They are listed below with the number of vendors carrying each, read from live price data rather than a list kept by hand, which is why the calculator above offers exactly these as one-tap sizes. A handful of vendors (notably one carrying an unusually wide, closely-spaced ladder) sell additional odd-numbered sizes not shown here; the arithmetic applies to any size the same way.

Vial sizeVendors tracking this size
5 mg8
6 mg4
10 mg36
12 mg5
15 mg9
20 mg24
24 mg4
30 mg28
40 mg6
50 mg10
60 mg11

The arithmetic, worked

Concentration (mg/mL) equals the vial’s total mg divided by the water volume in mL. Micrograms per syringe unit, on a U-100 syringe (100 units = 1 mL), equals that concentration multiplied by 10. The table below reports both figures at two illustrative water volumes for each tracked size — as a statement of what each volume does to the concentration, not a recommendation of either:

Vial sizeAt 1 mL waterAt 2 mL water
5 mg5 mg/mL — 50 mcg/unit2.5 mg/mL — 25 mcg/unit
6 mg6 mg/mL — 60 mcg/unit3 mg/mL — 30 mcg/unit
10 mg10 mg/mL — 100 mcg/unit5 mg/mL — 50 mcg/unit
12 mg12 mg/mL — 120 mcg/unit6 mg/mL — 60 mcg/unit
15 mg15 mg/mL — 150 mcg/unit7.5 mg/mL — 75 mcg/unit
20 mg20 mg/mL — 200 mcg/unit10 mg/mL — 100 mcg/unit
24 mg24 mg/mL — 240 mcg/unit12 mg/mL — 120 mcg/unit
30 mg30 mg/mL — 300 mcg/unit15 mg/mL — 150 mcg/unit
40 mg40 mg/mL — 400 mcg/unit20 mg/mL — 200 mcg/unit
50 mg50 mg/mL — 500 mcg/unit25 mg/mL — 250 mcg/unit
60 mg60 mg/mL — 600 mcg/unit30 mg/mL — 300 mcg/unit

Doubling the water volume halves the concentration and halves the mcg delivered per unit drawn — the relationship is linear in both directions. The general dosage calculator runs this same arithmetic for any vial size and water volume, including ones outside the table above.

Units to draw, by vial size and dose

Every cell is the U-100 unit mark a given dose comes to, for a given vial strength, at 2 mL of bacteriostatic water. The rows are the vial sizes three or more tracked vendors carry; the columns are round dose values, chosen so the table reads cleanly across that range. They are not a schedule and nothing here suggests one — retatrutide’s trial doses, with their registry numbers and arms, are set out in the retatrutide dosing guide.

Vial1 mg2 mg3 mg4 mg6 mg8 mg10 mg12 mg
5 mg40.080.0120.0160.0240.0320.0400.0480.0
6 mg33.366.7100.0133.3200.0266.7333.3400.0
10 mg20.040.060.080.0120.0160.0200.0240.0
12 mg16.733.350.066.7100.0133.3166.7200.0
15 mg13.326.740.053.380.0106.7133.3160.0
20 mg10.020.030.040.060.080.0100.0120.0
24 mg8.316.725.033.350.066.783.3100.0
30 mg6.713.320.026.740.053.366.780.0
40 mg5.010.015.020.030.040.050.060.0
50 mg4.08.012.016.024.032.040.048.0
60 mg3.36.710.013.320.026.733.340.0

Figures over 100 are shown in amber: they exceed a 1 mL U-100 barrel at this water volume, so that combination does not fit one syringe. More water lowers the concentration and raises the unit count; less water does the reverse. The calculator above works any vial, volume and dose, in either direction.

What one vial comes to

The three sizes the most tracked vendors carry, worked at 2 mL. “Doses per vial” is the vial’s total divided by the dose — how many times that amount is present in the vial, before any loss in handling.

10 mg vial at 2 mL — 5.00 mg/mL

DoseUnits to drawDraw volumeDoses per vial
1 mg20.00.20 mL10.0
2 mg40.00.40 mL5.0
3 mg60.00.60 mL3.3
4 mg80.00.80 mL2.5
6 mg120.01.20 mL1.7
8 mg160.01.60 mL1.3
10 mg200.02.00 mL1.0
12 mg240.02.40 mL0.8

30 mg vial at 2 mL — 15.00 mg/mL

DoseUnits to drawDraw volumeDoses per vial
1 mg6.70.07 mL30.0
2 mg13.30.13 mL15.0
3 mg20.00.20 mL10.0
4 mg26.70.27 mL7.5
6 mg40.00.40 mL5.0
8 mg53.30.53 mL3.8
10 mg66.70.67 mL3.0
12 mg80.00.80 mL2.5

20 mg vial at 2 mL — 10.00 mg/mL

DoseUnits to drawDraw volumeDoses per vial
1 mg10.00.10 mL20.0
2 mg20.00.20 mL10.0
3 mg30.00.30 mL6.7
4 mg40.00.40 mL5.0
6 mg60.00.60 mL3.3
8 mg80.00.80 mL2.5
10 mg100.01.00 mL2.0
12 mg120.01.20 mL1.7

What changes the answer

  • Water volume. Concentration is inversely proportional to water volume — the table above shows this directly. A larger water volume produces a lower concentration, meaning more units are needed to reach the same mg amount, which can exceed a syringe’s barrel capacity at low concentrations and high mg amounts.
  • Vial size. For a fixed water volume, concentration is directly proportional to vial size — a 20 mg vial reconstituted with 1 mL is twice the concentration of a 10 mg vial reconstituted the same way.
  • Syringe calibration. Every figure above assumes a U-100 syringe (100 units = 1 mL), the standard for peptide research (see the syringes and injection guide). A different calibration — U-40, for instance — would report a different units figure for the identical physical volume; it does not change the concentration or the mg delivered.

How long does reconstituted retatrutide last?

Retatrutide has no FDA-approved product and therefore no manufacturer label of any kind — not for the lyophilized powder, and not for a reconstituted solution. ClinicalTrials.gov’s own record for retatrutide’s pre-approval expanded-access program describes retatrutide itself as “an investigational GLP-1/GIP/glucagon triple receptor agonist.”

Prof. Peptide has not identified a sourced figure for how long reconstituted research-grade retatrutide remains stable, refrigerated or otherwise, from any manufacturer, regulator, or published study. This page does not state one as fact. A vendor’s own product page may state a shelf-life figure; that is the vendor’s claim, not an independently verified one, and is outside what this page reports.

FAQ

What is reconstitution?
Reconstitution is dissolving a lyophilized (freeze-dried) peptide powder in a liquid — typically bacteriostatic water — to turn it into a solution that can be measured with a syringe. The peptide's total mass doesn't change; dissolving it in liquid just makes it measurable in volume.
Does the water volume change how much peptide is in the vial?
No. A 10 mg vial contains 10 mg of retatrutide regardless of how much water is added. What changes is the concentration — milligrams per milliliter — and therefore how many syringe units correspond to a given milligram amount.
What syringe do the unit figures on this page assume?
A U-100 insulin syringe, where 100 units equals 1 mL. This is the standard syringe for peptide research — see the syringes and injection guide for barrel sizes and needle gauge.
Why doesn't this page say how much water to add or what dose to draw?
Both of those require choosing a number for the reader — a reconstitution volume and a target dose — and this page reports arithmetic, not a chosen protocol. The tables below show what a given water volume does to a given vial's concentration; how much water to use and what to inject are decisions outside what this page states.
What if my vial's size isn't in the table below?
The table covers sizes carried by 3 or more tracked vendors. A size outside that list can still be worked the same way: concentration (mg/mL) equals the vial's total mg divided by the water volume in mL, and mcg per syringe unit equals that concentration times 10 (on a U-100 syringe). The general dosage calculator performs this for any size.
Is a “reta calculator” the same as a retatrutide calculator?
Yes. “Reta” is a common short form of retatrutide, and the two terms refer to the same compound. This page is the retatrutide calculator; the abbreviation changes nothing about the arithmetic.
How much BAC water for a 5mg retatrutide vial?
A 5 mg vial holds 5 mg of retatrutide whatever volume of bacteriostatic water is added — the water sets the concentration, not the amount in the vial. At 1 mL that vial reads 5 mg/mL, so one unit on a U-100 syringe carries 50 mcg. At 2 mL it reads 2.50 mg/mL and one unit carries 25 mcg. At 3 mL it reads 1.67 mg/mL and one unit carries 16.7 mcg. Which of those volumes to add is a choice this page does not make; the calculator above works any combination, in either direction.
How much BAC water for a 6mg retatrutide vial?
A 6 mg vial holds 6 mg of retatrutide whatever volume of bacteriostatic water is added — the water sets the concentration, not the amount in the vial. At 1 mL that vial reads 6 mg/mL, so one unit on a U-100 syringe carries 60 mcg. At 2 mL it reads 3.00 mg/mL and one unit carries 30 mcg. At 3 mL it reads 2.00 mg/mL and one unit carries 20.0 mcg. Which of those volumes to add is a choice this page does not make; the calculator above works any combination, in either direction.
How much BAC water for a 10mg retatrutide vial?
A 10 mg vial holds 10 mg of retatrutide whatever volume of bacteriostatic water is added — the water sets the concentration, not the amount in the vial. At 1 mL that vial reads 10 mg/mL, so one unit on a U-100 syringe carries 100 mcg. At 2 mL it reads 5.00 mg/mL and one unit carries 50 mcg. At 3 mL it reads 3.33 mg/mL and one unit carries 33.3 mcg. Which of those volumes to add is a choice this page does not make; the calculator above works any combination, in either direction.
How much BAC water for a 12mg retatrutide vial?
A 12 mg vial holds 12 mg of retatrutide whatever volume of bacteriostatic water is added — the water sets the concentration, not the amount in the vial. At 1 mL that vial reads 12 mg/mL, so one unit on a U-100 syringe carries 120 mcg. At 2 mL it reads 6.00 mg/mL and one unit carries 60 mcg. At 3 mL it reads 4.00 mg/mL and one unit carries 40.0 mcg. Which of those volumes to add is a choice this page does not make; the calculator above works any combination, in either direction.
How much BAC water for a 15mg retatrutide vial?
A 15 mg vial holds 15 mg of retatrutide whatever volume of bacteriostatic water is added — the water sets the concentration, not the amount in the vial. At 1 mL that vial reads 15 mg/mL, so one unit on a U-100 syringe carries 150 mcg. At 2 mL it reads 7.50 mg/mL and one unit carries 75 mcg. At 3 mL it reads 5.00 mg/mL and one unit carries 50.0 mcg. Which of those volumes to add is a choice this page does not make; the calculator above works any combination, in either direction.
How much BAC water for a 20mg retatrutide vial?
A 20 mg vial holds 20 mg of retatrutide whatever volume of bacteriostatic water is added — the water sets the concentration, not the amount in the vial. At 1 mL that vial reads 20 mg/mL, so one unit on a U-100 syringe carries 200 mcg. At 2 mL it reads 10.00 mg/mL and one unit carries 100 mcg. At 3 mL it reads 6.67 mg/mL and one unit carries 66.7 mcg. Which of those volumes to add is a choice this page does not make; the calculator above works any combination, in either direction.
How much BAC water for a 24mg retatrutide vial?
A 24 mg vial holds 24 mg of retatrutide whatever volume of bacteriostatic water is added — the water sets the concentration, not the amount in the vial. At 1 mL that vial reads 24 mg/mL, so one unit on a U-100 syringe carries 240 mcg. At 2 mL it reads 12.00 mg/mL and one unit carries 120 mcg. At 3 mL it reads 8.00 mg/mL and one unit carries 80.0 mcg. Which of those volumes to add is a choice this page does not make; the calculator above works any combination, in either direction.
How much BAC water for a 30mg retatrutide vial?
A 30 mg vial holds 30 mg of retatrutide whatever volume of bacteriostatic water is added — the water sets the concentration, not the amount in the vial. At 1 mL that vial reads 30 mg/mL, so one unit on a U-100 syringe carries 300 mcg. At 2 mL it reads 15.00 mg/mL and one unit carries 150 mcg. At 3 mL it reads 10.00 mg/mL and one unit carries 100.0 mcg. Which of those volumes to add is a choice this page does not make; the calculator above works any combination, in either direction.
How much BAC water for a 40mg retatrutide vial?
A 40 mg vial holds 40 mg of retatrutide whatever volume of bacteriostatic water is added — the water sets the concentration, not the amount in the vial. At 1 mL that vial reads 40 mg/mL, so one unit on a U-100 syringe carries 400 mcg. At 2 mL it reads 20.00 mg/mL and one unit carries 200 mcg. At 3 mL it reads 13.33 mg/mL and one unit carries 133.3 mcg. Which of those volumes to add is a choice this page does not make; the calculator above works any combination, in either direction.
How much BAC water for a 50mg retatrutide vial?
A 50 mg vial holds 50 mg of retatrutide whatever volume of bacteriostatic water is added — the water sets the concentration, not the amount in the vial. At 1 mL that vial reads 50 mg/mL, so one unit on a U-100 syringe carries 500 mcg. At 2 mL it reads 25.00 mg/mL and one unit carries 250 mcg. At 3 mL it reads 16.67 mg/mL and one unit carries 166.7 mcg. Which of those volumes to add is a choice this page does not make; the calculator above works any combination, in either direction.
How much BAC water for a 60mg retatrutide vial?
A 60 mg vial holds 60 mg of retatrutide whatever volume of bacteriostatic water is added — the water sets the concentration, not the amount in the vial. At 1 mL that vial reads 60 mg/mL, so one unit on a U-100 syringe carries 600 mcg. At 2 mL it reads 30.00 mg/mL and one unit carries 300 mcg. At 3 mL it reads 20.00 mg/mL and one unit carries 200.0 mcg. Which of those volumes to add is a choice this page does not make; the calculator above works any combination, in either direction.

References

  1. ClinicalTrials.gov. Pre-approval Expanded Access of Retatrutide (LY3437943), NCT07629401. https://clinicaltrials.gov/study/NCT07629401

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