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HGH (Somatropin) Reconstitution Calculator

Recombinant human growth hormone, a prescription drug measured in international units; 1 mg is about 3 IU. Enter your vial size, the water you add, and your dose to see the units to draw. Defaults: 10 mg vial, 2 mL water, 2 IU per dose.

Math only. The dose itself comes from your prescriber or protocol; this page does not recommend one.

Excel: the button above exports this calculation as a spreadsheet with live formulas, or download the blank template.

How to reconstitute HGH (Somatropin)

HGH (Somatropin) is sold as a freeze-dried powder, most often in 4 mg, 5 mg, 10 mg, 12 mg vials. Add bacteriostatic water, let it dissolve without shaking, and the concentration is the vial amount divided by the water: 10 mg in 2 mL is 5 mg/mL. On a U-100 insulin syringe one unit is 0.01 mL, so each unit carries 50 mcg, and a 2 IU dose is 13.3 units.

Prescription only. Adult replacement is commonly 1 to 4 IU a day, set by the prescriber. This page converts IU at 3 IU per mg. Nothing on this page is a dosing recommendation; the calculator converts a dose you already have into syringe units.

HGH (Somatropin) doses in syringe units (10 mg vial, 2 mL water)

DoseUnitsmLDoses per vial
1 IU6.70.06730
2 IU13.30.13314
3 IU200.210
4 IU26.70.2677

Vial sizes at 2 IU per dose

VialWaterConcentrationUnits per doseDoses
4 mg2 mL2 mg/mL33.45
5 mg2 mL2.5 mg/mL26.77
10 mg2 mL5 mg/mL13.314
12 mg2 mL6 mg/mL11.117

The dose column is in IU. Doubling the water halves the concentration and doubles the units per dose; the number of doses in the vial never changes. If a dose comes out under 5 units, use less water so it is easier to measure. If it exceeds the syringe, use more water or a bigger syringe.

Worked example

10 mg / 2 mL = 5 mg/mL = 5,000 mcg/mL. One unit = 0.01 mL = 50 mcg. 667 mcg / 50 mcg per unit = 13.3 units. The vial holds 10,000 / 667 = 14 doses, which at 7 per week is about 14 days.

See the general peptide calculator for the formulas, syringe sizes, and the common mg versus mcg mistakes.

Frequently asked questions

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

With 10 mg in 2 mL of bacteriostatic water the concentration is 5 mg/mL, each unit holds 50 mcg, and 2 IU is 13.3 units (0.133 mL). Change the water and the units change with it.

How much bacteriostatic water do I add to a 10 mg vial of HGH (Somatropin)?

Any volume gives the same doses; 2 mL is a common choice because it keeps 2 IU at 13.3 units, which is easy to read on an insulin syringe. Use the calculator's round-number table to pick a volume that fits your syringe.

How long does a 10 mg vial of HGH (Somatropin) last?

At 2 IU per dose the vial holds 14 doses. At 7 doses a week that is about 14 days. Reconstituted vials are usually refrigerated and used within about four weeks.

What is the HGH (Somatropin) dose?

Prescription only. Adult replacement is commonly 1 to 4 IU a day, set by the prescriber. This page converts IU at 3 IU per mg. This calculator only converts a dose you already have into syringe units.

How do IU convert to mg for HGH?

Somatropin is standardized at about 3 IU per mg, so a 10 mg vial is 30 IU and 2 IU is 0.667 mg (667 mcg). Some products state their own IU per mg on the label; use that if it differs.

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