Reconstitution calculator
Vial mass, water added and dose per administration: the page returns the concentration, the volume and how many units to draw into a U-100 syringe. It only does the math. The dose is yours to bring, and it does not become any safer for being calculated.
The math is exact. The vial is not.
The calculator believes the label. If the vial says 10 mg, it does the math with 10 mg. A product sold as "research use only" has not been controlled for identity, purity or dosage for human use: if the powder holds 7 mg, every dose comes out 30% lower than the screen says, and nothing on this page can notice. More in Safety and limits.
It also does not know whether the dose typed in is safe, appropriate or studied for anyone. Nothing here is medical advice, a prescription or a treatment plan.
Draw into the U-100 syringe
- Concentration
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- Volume to draw
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- Doses per vial
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Fill in the vial mass, the water and the dose with numbers greater than zero.
Vial and water already give the concentration. The dose per administration is still needed for the volume and the units.
unit
units
exact figure: {x} doses
The dose is larger than the whole content of the vial. Check that dose and vial are in the same unit: mg and mcg differ by a factor of a thousand.
{u} do not fit in a {ml} mL syringe, which goes up to {cap} units. With less water in the vial the same powder becomes more concentrated, and the volume of each dose drops.
The reverse calculation needs the vial mass and the dose.
For {d} to take up {u}, put {a} mL of water in the vial.
That goes beyond the chosen syringe, which goes up to {cap} units.
Very small volume: {u}. In this range, one unit more or less on the syringe changes the dose by about {pct}%. With more water in the vial, the same dose takes up more units and reading error weighs less.
The math gave {u}, and the syringe is read by tick mark. At {a} the dose delivered is {da}; at {b}, it is {db}. Check the spacing of the marks on your syringe's scale.
Result: {u} in the U-100 syringe, {v} mL, concentration of {c} mg/mL.
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How the math works
Three divisions, always the same, and they can be redone on paper:
- Concentration = vial mass ÷ water added. A 10 mg vial with 2 mL of water ends up at 5 mg/mL.
- Dose volume = dose ÷ concentration. A 0.25 mg dose at 5 mg/mL takes up 0.05 mL.
- Units in the U-100 syringe = volume × 100, because in it 100 units are 1 mL. The 0.05 mL are 5 units.
And doses per vial = vial mass ÷ dose: 10 mg ÷ 0.25 mg gives 40. The calculator shows the whole number and the exact figure, because what is left at the end of the vial is not a dose. Open this example in the calculator.
The reverse calculation is the same one, backwards: water = units × vial mass ÷ (100 × dose). For the 0.25 mg dose from the 10 mg vial to take up 10 units, that is 10 × 10 ÷ (100 × 0.25) = 4 mL of water.
A unit is volume, not dose
The syringe unit measures liquid, not peptide. On the U-100 scale, each unit is one hundredth of a milliliter, in any syringe size: the 0.3 mL one goes up to 30 units, the 0.5 mL one up to 50 and the 1 mL one up to 100.
| Units (U-100) | Volume |
|---|---|
| 1 | 0.01 mL |
| 2 | 0.02 mL |
| 5 | 0.05 mL |
| 10 | 0.10 mL |
| 20 | 0.20 mL |
| 30 | 0.30 mL |
| 50 | 0.50 mL |
| 100 | 1.00 mL |
How much peptide goes into each unit depends on the vial concentration. The same 10-unit mark holds 0.5 mg in a vial at 5 mg/mL and 0.25 mg in a vial at 2.5 mg/mL. That is why "so many units" is not a dose: without the vial mass and the water, the number does not say how much was given.
What the math does not know
- Whether the vial holds what the label says. It is the limit that weighs most, and it is in the warning at the top of the page.
- Whether the syringe is U-100. The units here are valid only for it. Check the scale printed on the syringe barrel before using the number.
- What stays trapped in the syringe and the vial. Part of the liquid does not come out: it stays in the needle, the hub and on the vial walls. The number of doses per vial is the theoretical one.
- In a combined vial, the dose of each compound. A 10 mg blend with two peptides of 5 mg each has 5 mg of each. Enter the mass of the component you care about, and the math returns its dose.
- Whether the dose makes sense. The calculator has no dose list, does not compare against any study and does not warn about a high dose. What the evidence says about each compound is on its page, starting from the compounds.
The site's reconstitution tables
The protocol pages carry tables with vial, water, concentration and volume per dose. Their arithmetic is checked by an automatic lock that redoes each calculation and blocks publication of any table that does not add up. The lock was created after a manual audit found, in one of these tables, a volume published with the wrong separator — a thousand times the correct value, as read in Portuguese. The calculator uses the same three divisions. The difference is that in the tables the dose came from a secondary source; here, it comes from whoever types it.