Free Calculator
HGH Reconstitution Calculator
Enter the vial strength in IU or mg, the liquid added and your prescribed dose. You get the IU/mL and mg/mL concentration, the exact line on a U-100 syringe, how many doses the vial holds, and how many you can use before the product’s discard date. It also shows the most common HGH mistake: syringe units are not IU.
- Runs in your browser. Nothing is sent or stored
- For prescribed doses only
- Last updated: September 2026
Your dose on the syringe
Draw to U-100 syringe
—
—
Concentration
—
—
Drawn to scale for the barrel you picked. Zero is at the needle end.
Syringe units for other amounts in this vial
| IU | mg | Volume | U-100 units | On your syringe |
|---|
A conversion table for this vial, not a dosing guide.
This calculator does arithmetic only. It does not recommend a dose. Growth hormone is a prescription medicine. Use only the dose, product and instructions from your prescriber, and ask your pharmacist to check your first calculation.
The same amount four ways
What that draw contains
—
If you think you have injected more than prescribed, contact your doctor or pharmacist. In the US, Poison Control is 1-800-222-1222.
What Is an HGH Reconstitution Calculator?
Human growth hormone (HGH, or somatropin) often comes as a powder that must be mixed with a liquid before use. An HGH reconstitution calculator works out the strength of the mixed liquid. It then turns your prescribed dose, in IU or mg, into a volume and a line on your syringe.
Many prescription HGH products use pens or cartridges that do this for you. The calculator is for vials, or for checking your own understanding of a product’s strength.
How to use the HGH Reconstitution Calculator
- Enter the vial strength from the label, in IU or mg.
- Enter the liquid added. This is the diluent that came with the product, or the amount your pharmacist told you to use.
- Leave IU per mg at 3, unless your label gives a different figure.
- Enter your prescribed dose in IU or mg, and how many injections you take each week.
- Enter how long the mixed product lasts. Check your leaflet for this. It varies by brand.
- Read the results. You get the unit line, the concentration, a syringe picture, doses per vial and any waste at the discard date.
- Use the other tabs to convert any amount between IU, mg, mL and syringe units, or to check a dose you already drew.
How HGH Reconstitution Calculations Work
Every HGH calculation uses the same chain. You can start from IU or mg.
1. Total IU = vial mg × 3 (or read IU straight from the label)2. Concentration (IU/mL) = total IU ÷ liquid mL3. Volume (mL) = dose IU ÷ concentration4. U-100 syringe units = volume × 100The factor of 3 comes from the World Health Organization’s international standard for somatropin, which assigns 3.0 IU per mg. Older products sometimes used slightly different figures, which is why the calculator lets you change it.
HGH Vial Strength and Reconstitution Volume
Two numbers set everything else: how much HGH is in the vial, and how much liquid is added to it.
- Vial strength is the total amount. Prescription products are usually labelled in mg. Many online sources use IU. Always check which one your label shows.
- Reconstitution volume is the liquid added. Prescription products come with their own diluent and a fixed volume. Use exactly that amount unless your pharmacist says otherwise.
- The liquid does not change the dose, only the volume each dose takes up. A 10 IU vial holds 10 IU whether you add 1 mL or 2 mL.
Mixing tip
Add the liquid slowly down the inside wall of the vial and swirl gently. Do not shake. HGH is a large, fragile protein, and product leaflets warn against shaking. Do not use the solution if it is cloudy or has particles.
HGH IU to mL Conversion
To turn IU into mL, divide the IU you need by the IU in each mL of your mix.
mL = dose IU ÷ concentration IU/mL| Dose | At 5 IU/mL | At 10 IU/mL | At 15 IU/mL | At 36 IU/mL |
|---|---|---|---|---|
| 0.5 IU | 0.10 mL | 0.05 mL | 0.033 mL | 0.014 mL |
| 1 IU | 0.20 mL | 0.10 mL | 0.067 mL | 0.028 mL |
| 2 IU | 0.40 mL | 0.20 mL | 0.133 mL | 0.056 mL |
| 3 IU | 0.60 mL | 0.30 mL | 0.20 mL | 0.083 mL |
HGH mg to mL Concentration Calculator
If your label shows mg, work in mg/mL instead:
Concentration (mg/mL) = vial mg ÷ liquid mLmL = dose mg ÷ concentration mg/mLFor example, 5 mg mixed with 1 mL is 5 mg/mL. A 0.3 mg dose is 0.3 ÷ 5 = 0.06 mL, or 6 units on a U-100 syringe. The same 5 mg vial holds 15 IU, so 0.3 mg is also 0.9 IU.
| mg | IU (at 3 IU/mg) |
|---|---|
| 0.1 mg | 0.3 IU |
| 0.33 mg | 1 IU |
| 1 mg | 3 IU |
| 4 mg | 12 IU |
| 5 mg | 15 IU |
| 12 mg | 36 IU |
HGH IU/mL Concentration Calculator
IU/mL tells you how many IU are in each millilitre of your mixed vial.
Concentration (IU/mL) = vial IU ÷ liquid mL| Vial | 1 mL | 2 mL | 3 mL |
|---|---|---|---|
| 10 IU | 10 IU/mL | 5 IU/mL | 3.33 IU/mL |
| 12 IU (4 mg) | 12 IU/mL | 6 IU/mL | 4 IU/mL |
| 15 IU (5 mg) | 15 IU/mL | 7.5 IU/mL | 5 IU/mL |
| 36 IU (12 mg) | 36 IU/mL | 18 IU/mL | 12 IU/mL |
How to Calculate the Concentration of a Reconstituted HGH Vial
- Find the total amount. Read it from the label. If it is in mg, multiply by 3 to get IU.
- Find the total liquid. This is the diluent volume you added.
- Divide. Total IU ÷ total mL = IU/mL. Total mg ÷ total mL = mg/mL.
- Write it on the vial with the date mixed. The “Copy vial label” button in Tab 1 gives you the text.
If you forget how much liquid you added, the concentration is unknown, and so is every dose from that vial. Do not guess. Ask your pharmacist.
HGH Reconstitution Calculation Examples
Example 1: 10 IU vial, 1 mL, 1 IU dose
10 ÷ 1 = 10 IU/mL. 1 ÷ 10 = 0.1 mL, which is 10 units on a U-100 syringe.
Example 2: 10 IU vial, 2 mL, 1 IU dose
10 ÷ 2 = 5 IU/mL. 1 ÷ 5 = 0.2 mL, which is 20 units. The same dose takes twice the units.
Example 3: 5 mg vial, 1 mL, 0.2 mg dose
5 mg = 15 IU, so 15 IU/mL (or 5 mg/mL). 0.2 mg ÷ 5 = 0.04 mL, which is 4 units. That is 0.6 IU.
Example 4: 36 IU vial, 1 mL, 2 IU dose
36 IU/mL. 2 ÷ 36 = 0.056 mL, which is 5.6 units. This falls between lines and is hard to measure. With 2 mL the mix is 18 IU/mL, and 2 IU becomes 11.1 units. With 3 mL (12 IU/mL) it is 16.7 units.
HGH U-100 Syringe Unit Conversion
On a U-100 insulin syringe, 1 unit = 0.01 mL, whatever is inside. To find how much HGH one unit line holds, divide your concentration by 100.
IU per syringe unit = concentration IU/mL ÷ 100| Concentration | 1 syringe unit holds | 1 IU takes |
|---|---|---|
| 5 IU/mL | 0.05 IU | 20 units |
| 10 IU/mL | 0.1 IU | 10 units |
| 15 IU/mL | 0.15 IU | 6.7 units |
| 20 IU/mL | 0.2 IU | 5 units |
| 36 IU/mL | 0.36 IU | 2.8 units |
Why Syringe Units and IU Are Not the Same
This is the most common HGH mix-up, because both are called “units”.
- A syringe unit is a volume mark: 0.01 mL on a U-100 syringe.
- An IU (international unit) is a measure of biological activity. For somatropin, 3 IU = 1 mg.
- They only match at one strength. Syringe units equal IU only when the mix is exactly 100 IU/mL. HGH is almost never mixed that strong.
What this looks like in practice
A prescription says “1 IU”. At 10 IU/mL, that is 10 syringe units. Someone who draws to the “1” line has taken 0.1 IU, one tenth of the dose. Someone who reads “10 units” as 10 IU and takes 10 IU has taken ten times the dose. Tab 3 of the calculator checks for this.
Common HGH Reconstitution Calculation Errors
- Treating syringe units as IU. They are only equal at 100 IU/mL.
- Mixing up mg and IU. 1 mg is 3 IU. A dose written in mg and drawn as IU is off by three times.
- Copying a units number from someone else. It only works for their exact vial and liquid.
- Mixing too strong. Very small volumes, such as 2 to 3 units, are hard to measure accurately.
- Shaking the vial. This can damage the protein.
- Using a mixed vial past its limit. Storage time after mixing is set by each product’s leaflet.
- Trusting an unverified label. HGH sold without a prescription may be fake, under-strength or contaminated. The FDA has an import alert for unapproved HGH, including powders sold for reconstitution. The maths cannot fix a wrong label.
Legal and safety note
In the US, federal law allows growth hormone to be distributed only for specific approved uses. A 2005 review in JAMA noted that providing it for anti-ageing is illegal. It is also banned in sport. Possible side effects include fluid retention, joint pain, carpal tunnel symptoms and raised blood sugar. Use it only under the care of a prescriber who monitors you.
HGH Reconstitution Calculator FAQs
How many IU are in 1 mg of HGH?
The WHO international standard for somatropin is 3 IU per mg. So 1 mg = 3 IU, 5 mg = 15 IU and 12 mg = 36 IU.
How many units on an insulin syringe is 1 IU of HGH?
It depends on the mix. At 10 IU/mL, 1 IU is 10 units. At 5 IU/mL, it is 20 units. At 36 IU/mL, it is about 2.8 units. Divide 100 by your IU/mL to get the units for 1 IU.
How much water do I add to a 10 IU HGH vial?
Use the diluent and volume from your product or pharmacist. The volume only sets the strength. With 1 mL, 10 IU becomes 10 IU/mL, so each IU is 10 syringe units. With 2 mL, each IU is 20 units.
Are syringe units the same as IU?
No. A syringe unit is 0.01 mL of liquid. An IU measures the hormone itself. They are only equal if the mix is exactly 100 IU/mL, which is very rare for HGH.
How long does reconstituted HGH last?
It depends on the product. Check the leaflet for how long a mixed vial or cartridge can be kept, and keep it in the fridge unless told otherwise. The calculator lets you enter your product’s limit, and shows any doses that would be left over.
Can I use bacteriostatic water for HGH?
Use the diluent supplied with your product. Some HGH products come with a preserved diluent and some with plain sterile water, and the choice can affect how long the mixed product lasts. Ask your pharmacist before swapping.
Does this calculator store my information?
No. Everything runs in your browser. Nothing is sent, saved or shared.
Sources and further reading
- National Institute for Biological Standards and Control (NIBSC). WHO International Standard, Somatropin, NIBSC code 98/574. nibsc.org
- Perls TT, Reisman NR, Olshansky SJ. Provision or distribution of growth hormone for “antiaging”: clinical and legal issues. JAMA. 2005;294(16):2086–2090. Summary: sciencedaily.com
- US Food and Drug Administration. Import Alert 66-71. accessdata.fda.gov
Reviewed and updated: September 2026.