How many units is 2 IU of HGH (somatropin)?

It depends entirely on how much water you added. In a 10 IU vial reconstituted with 1 mL, the concentration is 10 IU/mL, so 2 IU is 0.2 mL, which is 20 units on a U-100 insulin syringe. In the same vial with 0.5 mL of water it is 10 units, and with 1.5 mL it is 30 units.

How much bacteriostatic water for a 10 IU HGH (somatropin) vial?

1 mL is the usual choice. It gives 10 IU/mL, which puts the commonly reported range of 0.5 IU to 6 IU between roughly 5 and 60 units. Aim for a draw between about 10 and 50 units, where the barrel is easiest to read, and add or remove water to get there.

How many doses are in a 10 IU vial?

Divide 10 by your dose. At 2 IU that is 5 doses, which at once daily is 5 days.

How many units is 2 IU of HGH?

It depends on the water. A 10 IU vial with 1 mL of water is 10 IU/mL, so 2 IU is 0.2 mL, which is 20 units on a U-100 insulin syringe. With 2 mL of water the same 2 IU is 40 units.

How many mg is 10 IU of HGH?

About 3.3 mg. The conversion for somatropin is roughly 3 IU per mg. You do not need it for the calculator, which works in IU throughout.

HGH (somatropin) dosage calculator

In a 10 IU vial with 1 mL of water (10 IU/mL), 2 IU of HGH (somatropin) is 20 units on a U-100 insulin syringe. Growth hormone is the one compound here labelled in IU rather than mg. Enter the IU on your vial, the water you added and your IU dose to get the mark on the syringe.

Reviewed 3 September 2026
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Dose to units at the usual vial and water

Dose	U-100 units	Draw	Doses per vial	Vial lasts
1 IU	10 units	0.1 mL	10	10 days
2 IU	20 units	0.2 mL	5	5 days
3 IU	30 units	0.3 mL	3	3 days
4 IU	40 units	0.4 mL	2	2 days
5 IU	50 units	0.5 mL	2	2 days
6 IU	60 units	0.6 mL	1	1 day

10 IU vial in 1 mL of bacteriostatic water (10 IU/mL), U-100 insulin syringe, once daily.

About HGH (somatropin)

Somatropin is recombinant human growth hormone, a 191 amino acid protein. It is a prescription medicine with licensed uses, and any use outside a prescription is unlicensed. Vials sold as research material are not the licensed product.

The unit confusion here is specific: the vial is labelled in international units (IU), not milligrams, and the syringe is labelled in insulin units. They are unrelated. 1 mg of somatropin is roughly 3 IU. A 10 IU vial reconstituted with 1 mL gives 10 IU per mL, so 2 IU is 0.2 mL, which is 20 units on a U-100 insulin syringe. That 20 has nothing to do with the IU figure; it is a volume.

Growth hormone is fragile once reconstituted. Swirl, never shake, and keep it refrigerated. Reported protocols commonly run 1 to 4 IU per day, often split, but that is a description of what people report and not a recommendation.

IU, mg and syringe units: three different numbers

A growth hormone dose can be written three ways, and they are not interchangeable. IU (international units) is what most research vials print. mg is what prescriptions and many trials use; somatropin labels put 1 mg at 3 IU (the Genotropin cartridges are 5.3 mg, labelled 16 IU, and 12 mg, labelled 36 IU). Units on an insulin syringe are only volume: 100 of them are 1 mL. The calculator works in IU; this table starts from mg for anyone whose dose is written that way.

Dose in mg	Same dose in IU	10 IU vial + 1 mL (10 IU/mL)	10 IU vial + 2 mL (5 IU/mL)	36 IU vial + 3 mL (12 IU/mL)
0.2 mg	0.6 IU	6 units	12 units	5 units
0.3 mg	0.9 IU	9 units	18 units	7.5 units
0.5 mg	1.5 IU	15 units	30 units	12.5 units
0.6 mg	1.8 IU	18 units	36 units	15 units
1 mg	3 IU	30 units	60 units	25 units
1.5 mg	4.5 IU	45 units	90 units	37.5 units
2 mg	6 IU	60 units	120 units (over one 1 mL syringe)	50 units

mg to IU at 3 IU per mg, then IU to units on a U-100 insulin syringe. A 36 IU vial is the 12 mg size.

Three worked examples

A dose written as 0.6 mg. 0.6 × 3 is 1.8 IU. From a 10 IU vial with 1 mL of water (10 IU/mL) that is 0.18 mL, so the mark is 18 units.

3 IU from a 36 IU vial. With 3 mL of water it is 12 IU/mL, so 3 IU is 0.25 mL: 25 units. Mix the same vial with only 1 mL and 2 IU becomes 5.6 units, too small to read reliably, which is why bigger vials take more water.

Reading "2 IU" as "2 on the syringe". At 10 IU/mL, 2 IU is 20 units. Drawing to the 2 mark instead gives 0.02 mL, which is 0.2 IU, a tenth of the dose.

Common mistakes

Treating IU and syringe units as the same thing. They only line up at 100 IU/mL, which no common setup uses.
Mixing up mg and IU. 1 mg is about 3 IU, so a dose read in the wrong one is three times too high or a third too low.
Shaking the vial. Growth hormone is a large protein. Let the water run down the side and swirl gently; keep it cold once mixed.
Forgetting the water you actually used. A 10 IU vial is 10 IU/mL with 1 mL but 5 IU/mL with 2 mL, so the same dose is twice the units. Write the water volume on the vial.

Sources

Pfizer: Genotropin prescribing information. 5.3 mg = 16 IU and 12 mg = 36 IU per mL once mixed; 3 IU per mg.

The same 10 IU vial at other water volumes

If the draw is awkward to read, change the water, not the dose. The dose stays the same; only the mark moves.

Vial	BAC water	Concentration	Draw	U-100 units	Doses/vial
10 IU	1 mL	10 IU/mL	0.2 mL	20 units	5
10 IU	2 mL	5 IU/mL	0.4 mL	40 units	5
10 IU	3 mL	3.33 IU/mL	0.6 mL	60 units	5
12 IU	1 mL	12 IU/mL	0.167 mL	16.7 units	6
12 IU	2 mL	6 IU/mL	0.333 mL	33.3 units	6
12 IU	3 mL	4 IU/mL	0.5 mL	50 units	6

All rows above assume a 2 IU dose and a standard U-100 insulin syringe, where 100 units = 1 mL.

How long it lasts in the body

The half-life of HGH (somatropin) is about 3.8 hours. That is the time for the amount in your blood to halve, so after one half-life you are at 50 percent of the peak, after two you are at 25 percent, and after four you are at roughly 6 percent. This is why it is dosed daily or more often: by the next morning almost none of the previous dose is left, and there is no build-up from day to day.

Common questions

How many units is 2 IU of HGH (somatropin)?: It depends entirely on how much water you added. In a 10 IU vial reconstituted with 1 mL, the concentration is 10 IU/mL, so 2 IU is 0.2 mL, which is 20 units on a U-100 insulin syringe. In the same vial with 0.5 mL of water it is 10 units, and with 1.5 mL it is 30 units.
How much bacteriostatic water for a 10 IU HGH (somatropin) vial?: 1 mL is the usual choice. It gives 10 IU/mL, which puts the commonly reported range of 0.5 IU to 6 IU between roughly 5 and 60 units. Aim for a draw between about 10 and 50 units, where the barrel is easiest to read, and add or remove water to get there.
How many doses are in a 10 IU vial?: Divide 10 by your dose. At 2 IU that is 5 doses, which at once daily is 5 days.
How many units is 2 IU of HGH?: It depends on the water. A 10 IU vial with 1 mL of water is 10 IU/mL, so 2 IU is 0.2 mL, which is 20 units on a U-100 insulin syringe. With 2 mL of water the same 2 IU is 40 units.
How many mg is 10 IU of HGH?: About 3.3 mg. The conversion for somatropin is roughly 3 IU per mg. You do not need it for the calculator, which works in IU throughout.

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The maths is openThe formula is on every page and in the methodology. The code is one file with an automated test suite, run before each deploy.

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ReviewedDose ranges and half-lives checked 3 September 2026.

Buying HGH (somatropin)?

Peptulator does not list, rank or link vendors. Whoever the supplier is, use the strength printed on your own vial and check the batch certificate of analysis before you rely on any number here.

MethodologyEvery formula and rounding rule, so you can check the maths Read a syringeU-100 vs U-40, and the 2.5x error Build a full protocolThe stack builder at Peptide Bureau, about two minutes

Common conversions

The same three-step maths, pre-filled for the doses people ask about most. Units on a U-100 insulin syringe, where 100 units is 1 mL.

mg to units calculator Any dose at any concentration, both directions, with the full reference tables
Units to mg calculator What the units you drew are in milligrams
1 mg to units The most-asked conversion, at every common setup

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Before you use these numbers This is a unit-conversion tool. It turns a vial strength and a water volume into a concentration, a draw volume and a syringe mark. It does not tell you what to take, whether to take it, or whether a compound is safe for you. Most compounds listed are sold for laboratory research and are not approved for human use. Nothing here is medical advice. Dosing decisions belong with a licensed clinician who knows your history. Always check the strength printed on your own vial rather than trusting a preset.