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Reproductive signaling research

HCG reconstitution calculator and reference

Research use: limited or no human data

Research HCG.

Category
Reproductive
Common vial sizes
5, 10 mg
Shelf life
30 days
refrigerated, mixed

Short answer: add 1 mL of bac water to a 5 mg HCG vial. A 500 mcg amount then measures about 10 units on a 1 mL (U-100) insulin syringe.

To mix a 5 mg vial of HCG, add about 1 mL of BAC water. Now each 1 mL of liquid holds 5 mg of peptide. So a 500 mcg dose is about 10 units on a 1 mL insulin syringe. Want a rounder number? Add a little more or a little less water.

What nobody knows

  • How much, if any, is safe for a person.
  • Whether it does anything in people, and what it does over the long term.
  • What is actually in your vial: the powder's identity, purity, and strength.
Compiled and maintained by the BACwater.ai editorial team and checked against the sources cited on this page. This is general research information, not a medical review. Last updated July 2026.

HCG bac water calculator

= 0.50 mg

Add this much bac water
1mL
Concentration
5 mg/mL
Per dose
10 units
Doses / vial
10

This is general reconstitution math for research and educational use only. BACwater.ai is not a medical company, and this is not medical advice. Always check your product's own paperwork and talk to your doctor before making any health decision. Read the full disclaimer.

What you cannot know about your vial

  • You cannot see what is really inside. Independent testing in this market has found research powders that were mislabeled, weaker or stronger than the label, or contaminated. An unlabeled vial tells you nothing you can verify.
  • “Research-grade” is not a standard. It is not a grade anyone checks. It does not promise that the powder is HCG, that it is pure, or that the amount matches the label.
  • No calculation fixes this. The math here is exact for the numbers you type. It cannot tell you whether the powder in your vial matches what is printed on it.
Read more: what you cannot know about your vial

What is HCG?

HCG is a hormone studied in reproductive research and typically supplied as a lyophilized research powder.

It is reconstituted the same way as peptides, but its strength is often stated in international units (IU) rather than milligrams.

Reproductive research peptides are reconstituted with bacteriostatic water using the standard method. Verify the strength and units printed on your vial carefully, since labeling conventions vary in this group.

How much bac water for HCG?

The chart below is a HCG reconstitution chart: each common vial size, the bac water to add, and where a 500 mcgmeasurement lands on a 1 mL insulin syringe. Use the calculator above for your exact vial and the amount you want to measure.

Vial amountBac water to addConcentrationAmount to measureSyringe units
5 mg1 mL5 mg/mL500 mcg10 units
10 mg2 mL5 mg/mL500 mcg10 units

The amount in the “Amount to measure” column is an example chosen so the math is easy to follow. It is not a recommended amount, and this site does not recommend how much to use. Units assume a U-100 insulin syringe (100 units = 1 mL). Always confirm the amount printed on your own vial.

HCG: concentration by vial size after reconstitutionHCG reconstitution reference: a 5 mg vial with 1 mL of bac water makes 5 mg/mL; a 10 mg vial with 2 mL of bac water makes 5 mg/mL. Concentration is the vial amount divided by the water added; no dose is assumed. BACwater .ai RECONSTITUTION REFERENCE HCG Concentration you get at each common vial size and bac water amount. 5 mg + 1 mL water 5 mg/mL 10 mg + 2 mL water 5 mg/mL Concentration = vial amount ÷ water added. Longer bar = stronger liquid. No dose is assumed and nothing is for sale.
HCG reconstitution reference: a 5 mg vial with 1 mL of bac water makes 5 mg/mL; a 10 mg vial with 2 mL of bac water makes 5 mg/mL. Concentration is the vial amount divided by the water added; no dose is assumed.

How to reconstitute HCG

  1. 1
    Gather your supplies

    Wash your hands and lay out your HCG vial, a vial of bacteriostatic water, an insulin syringe, and alcohol prep pads on a clean surface.

  2. 2
    Swab both vial tops

    Wipe the rubber stopper of both the peptide vial and the bacteriostatic water vial with separate alcohol prep pads. Let them air dry.

  3. 3
    Draw the bacteriostatic water

    For a 5 mg vial, draw about 1 mL of bacteriostatic water. Use the calculator on this page to match your exact vial strength.

  4. 4
    Add water to the peptide vial

    Insert the needle at an angle and let the water run slowly down the inside wall of the vial. Do not spray it directly onto the powder.

  5. 5
    Swirl gently

    Roll or swirl the vial between your palms until the powder fully dissolves. Roll it, do not shake it, if your product's instructions say so. The solution should look clear.

  6. 6
    Label and refrigerate

    Label the vial with the peptide name, the date mixed, and the expiration date, then refrigerate it immediately.

Storage and shelf life

30 days
refrigerated

Keep in the fridge. HCG strength is frequently labeled in IU, not mg. Confirm the units on your vial before using any milligram-based calculator, since the two are not interchangeable. Once you add bac water, the peptide slowly breaks down, so refrigerate the vial and discard it if the solution turns cloudy or develops particles.

HCG reconstitution FAQ

Add about 1 mL of bacteriostatic water to a 5 mg vial of HCG. That creates a 5 mg/mL solution, so a 500 mcg dose is about 10 units on a 1 mL insulin syringe. Adjust the water amount to move the dose to a cleaner mark.

Add about 2 mL of bacteriostatic water to a 10 mg vial of HCG. That creates a 5 mg/mL solution, so a 500 mcg dose is about 10 units on a 1 mL insulin syringe. Adjust the water amount to move the dose to a cleaner mark.

Once mixed, HCG is typically stable for about 30 days when refrigerated. Keep in the fridge. Discard it sooner if the solution turns cloudy or develops particles.

HCG is commonly measured in international units rather than milligrams. If your vial is labeled in IU, use the IU value your product documentation provides rather than a milligram-based calculation, since IU and mg are not directly interchangeable for HCG.
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References

Primary sources for the facts on this page. We cite regulatory and peer-reviewed authorities rather than secondary blogs.

  1. Bacteriostatic Water for Injection, USP - prescribing information · U.S. FDA labeling via DailyMed (NIH / NLM)Defines bacteriostatic water as sterile water with 0.9% benzyl alcohol added as a bacteriostatic preservative, supplied in a multiple-dose container for diluting or dissolving drugs; contraindicated in neonates.
  2. Benzyl alcohol (Compound CID 244) · NIH PubChem, National Library of MedicineChemical identity, properties, and safety data for benzyl alcohol, the bacteriostatic preservative in BAC water.
Ready to mix HCG?

The Plan Builder turns these numbers into a printable, step-by-step plan. You can also read how reconstitution works, brush up on the bac water calculator, or start from the complete bac water guide.