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HCG reconstitution calculator
HCG comes as a powder. The water you add is the only thing that decides its strength. The answer for the most common vial: 5,000 IU in 2 mL of bacteriostatic water gives 2,500 IU per mL, so every 10 units on a U-100 insulin syringe holds 250 IU. Enter your own vial and water below for the units to draw, then use the chart to pick a water volume that suits your dose.
Concentration (IU per mL) = vial IU ÷ water mL. On a U-100 syringe 100 units is 1 mL, so units to draw = dose IU ÷ concentration × 100. HCG is measured in IU, a unit of biological activity with no fixed weight, so a milligram-based peptide calculator cannot do this without a conversion that does not exist.
Runs in your browser; nothing you enter is sent anywhere. Results assume a U-100 insulin syringe. This is arithmetic for a dose your prescriber has already set, not a dose suggestion.
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There is no single correct volume. The powder is fixed, so the water only sets the concentration. The right volume is the one that puts your dose in a part of the syringe you can read. These are insulin units on the barrel, not IU:
| Water | Concentration | IU per unit | 250 IU | 500 IU | 1,000 IU |
|---|---|---|---|---|---|
| 1 mL | 5,000 IU/mL | 50 IU | 5 u | 10 u | 20 u |
| 2 mL | 2,500 IU/mL | 25 IU | 10 u | 20 u | 40 u |
| 3 mL | 1,667 IU/mL | 16.7 IU | 15 u | 30 u | 60 u |
| 5 mL | 1,000 IU/mL | 10 IU | 25 u | 50 u | 100 u |
| 10 mL | 500 IU/mL | 5 IU | 50 u | 100 u | 200 u (over 1 mL) |
Read the extremes to choose. At 1 mL a 250 IU dose is 5 units, where misreading one unit is a 20% error. At 5 mL the same dose is 25 units and much harder to get wrong. Small doses favor more water; large doses favor less, so a single draw still fits a 1 mL syringe.
The branded kits come with more water than most people need for small doses. Novarel ships each 5,000 or 10,000 IU vial with a 10 mL vial of bacteriostatic water. Its label describes two ways to use it: 1 mL to give the whole vial as one dose, or 10 mL for a multi-dose vial kept refrigerated between doses. Pregnyl's 10,000 IU vial comes with 10 mL of solvent preserved with benzyl alcohol. You do not have to add the whole 10 mL; the arithmetic works for any volume, as long as you write down the one you used.
2,000 and 10,000 IU vials
| Vial + water | Concentration | IU per unit | 250 IU | 500 IU | 1,000 IU |
|---|---|---|---|---|---|
| 2,000 IU + 1 mL | 2,000 IU/mL | 20 IU | 12.5 u | 25 u | 50 u |
| 2,000 IU + 2 mL | 1,000 IU/mL | 10 IU | 25 u | 50 u | 100 u |
| 2,000 IU + 3 mL | 667 IU/mL | 6.7 IU | 37.5 u | 75 u | 150 u (over 1 mL) |
| 10,000 IU + 1 mL | 10,000 IU/mL | 100 IU | 2.5 u | 5 u | 10 u |
| 10,000 IU + 2 mL | 5,000 IU/mL | 50 IU | 5 u | 10 u | 20 u |
| 10,000 IU + 5 mL | 2,000 IU/mL | 20 IU | 12.5 u | 25 u | 50 u |
| 10,000 IU + 10 mL | 1,000 IU/mL | 10 IU | 25 u | 50 u | 100 u |
A 10,000 IU vial in 1 mL puts a 250 IU dose at 2.5 units, which no insulin syringe marks reliably. If your doses are small, mix a large vial more dilute.
How to reconstitute HCG, step by step
Decide the water volume first. It sets the concentration for the life of the vial and cannot be changed afterward. Use the chart above to pick a volume that puts your usual dose in a readable part of the syringe.
Swab both stoppers. Wash your hands, then wipe the rubber stopper of the HCG vial and of the water with an alcohol swab and let them air dry.
Add the water down the vial wall. Let it run down the inside of the glass rather than jetting straight onto the powder. HCG is a fragile glycoprotein and a hard stream can damage it.
Swirl, never shake. Roll the vial gently until the powder dissolves and the liquid is clear. Shaking can denature the hormone and leaves foam that makes accurate draws harder. Cloudiness or particles mean do not use it.
Label it. Write the concentration in IU per mL and the date you mixed it on the vial. Concentration is invisible once it is in solution. An unlabeled vial is where most dosing errors start.
Refrigerate. Store it at 2–8 °C straight away and use it within the period your product's label gives (below).
Which water to use and how long it keeps
Bacteriostatic water contains 0.9% benzyl alcohol as a preservative, which is what lets one vial be used for several doses. Both branded kits supply a diluent preserved this way. How long the mixed vial keeps depends on the product, so read your own label:
- • Novarel: refrigerate the reconstituted product at 2–8 °C and use it within 30 days.
- • Pregnyl: the reconstituted solution is stable for 60 days when refrigerated.
- • Before mixing, both labels store the powder at room temperature.
Sterile water has no preservative. A vial mixed with it should be treated as single-use and discarded after one dose, however much is left. Keep a mixed vial out of light, do not freeze it and discard it if it turns cloudy, discolored or shows particles.
Common mistakes
- • Reading IU as syringe units. 250 IU is not 250 units. At 2,500 IU/mL it is 10 units.
- • Using a chart for a different vial or volume. 5,000 IU in 2 mL and 10,000 IU in 2 mL differ by a factor of two on every draw.
- • Not labeling the vial. A forgotten water volume cannot be recovered by looking at the liquid.
- • Mixing with sterile water and keeping the vial. Without a preservative it is single-use.
- • Running HCG through a milligram calculator. IU has no fixed weight, so the conversion step those tools need does not exist.
Chest pain, sudden weakness or numbness on one side, slurred speech or a cold, painful leg can mean a blood clot, which both the Novarel and Pregnyl labels list among the serious reactions reported in fertility treatment. Hives, a swollen face or throat or trouble breathing after a dose can be an allergic reaction. Get emergency care for either. An injection site that turns red, hot or increasingly painful, or a fever after injecting, needs a doctor. hCG is a prescription medicine, contraindicated in pregnancy and in prostate cancer. New swelling, breast tenderness or low mood, all listed side effects, are worth raising with your prescriber. This page explains the mixing arithmetic; it is not medical advice and does not suggest a dose.
Frequently asked questions
How much bacteriostatic water do I add to a 5,000 IU HCG vial?
Any volume works, because the water only sets the concentration. 2 mL gives 2,500 IU/mL (25 IU per unit), 5 mL gives 1,000 IU/mL (10 IU per unit). More water makes small doses easier to measure; less keeps large doses inside a 1 mL syringe. Write the volume on the vial.
How do I reconstitute a 10,000 IU vial of HCG?
The same way as any other size: add bacteriostatic water down the vial wall and swirl. 10 mL gives 1,000 IU/mL, which the Novarel label describes for multi-dose use. It puts 250 IU at 25 units. 5 mL gives 2,000 IU/mL and puts 250 IU at 12.5 units.
How many units is 250 IU of HCG?
It depends on how you mixed it. From 5,000 IU in 2 mL it is 10 units; in 5 mL it is 25 units. From 10,000 IU in 10 mL it is 25 units. Recalculate every time you mix a vial with a different volume.
How long does reconstituted HCG last?
Refrigerated at 2–8 °C, the Novarel label says to use it within 30 days and the Pregnyl label says it is stable for 60 days. Follow the label of the product you have. A vial mixed with sterile water has no preservative and is single-use.
Can I reconstitute HCG with sterile water instead of bacteriostatic water?
Only if you will use the whole vial in one dose. Sterile water has no preservative, so a vial mixed with it should be discarded after the first draw. For a vial you will dose from over days or weeks, use bacteriostatic water, which is what both branded kits supply.
Is this the same as the HCG dosage calculator?
Same arithmetic, other direction. This page starts from the vial and the water you add. The HCG dosage calculator starts from the dose your prescriber set and returns the units to draw from a vial you have already mixed.
Sources
- Novarel (chorionic gonadotropin for injection) prescribing information, Ferring Pharmaceuticals, revised August 2025: supplied diluent, reconstitution volumes, storage before and after mixing, warnings and contraindications. DailyMed
- Pregnyl (chorionic gonadotropin for injection, USP) prescribing information, Organon USA: supplied solvent, 60-day refrigerated stability, warnings and adverse reactions. FDA label (PDF)
The unit conversion is arithmetic and needs no citation. U-100 syringe: 100 units = 1 mL. Vial strengths vary between products, so check the strength printed on your own vial before calculating.
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