Calculator · U-100 insulin syringes
BAC water calculator
BAC water, short for bacteriostatic water, is sterile water with a preservative that slows the growth of germs. Type the amount of peptide in the vial and the dose you were told to use. Then pick how many units you want each dose to fill. See how much water to add.
Updated , by The Peptide Field Read our standards
Only a licensed clinician should set a dose. Talk with your doctor, nurse, or pharmacist before you use any number from this page. Ask them to work out the numbers on their own.
You use these results at your own risk. The Peptide Field is not liable for any dose measured or taken with them.
Water to add
Fill in: amount in the vial, dose you were told to use, units you want each dose to fill.
How the math works
More water spreads the same peptide thinner.
- Both vials hold the same amount of peptide. Each dot stands for a little of it.
- Water spreads the dots out. More water puts more space between them.
- So a draw of the same size holds fewer dots. With more water, you draw more units for the same dose.
Before you use these numbers
- Have your provider check the math first. Show your doctor, nurse, or pharmacist the vial, its label, and the numbers you typed. Ask them to work it out on their own.
- Check that the syringe says U-100. The FDA describes U-100 as 100 units in every mL. U-40 syringes hold 40 units in every mL, so the marks mean something else.
- Use the same unit as your instructions. Mixing up mg and mcg gives a dose 1,000 times too big or too small.
- Write down how much water went in the vial. You need that number each time you work out a dose.
- Using a pen? Pen clicks are not syringe units. Pens come mixed and marked by the maker, so follow the pen label, not this page.
- Use a new, sterile needle and syringe for every dose. Never share needles or syringes, and keep each vial for one person. The FDA and CDC both say this.
Took the wrong amount? Call Poison Help: 1-800-222-1222 It is free and open 24 hours a day, every day.
What this calculator cannot do
- It cannot tell you what dose to use. Only a licensed clinician should set a dose.
- It cannot check that the vial holds the amount printed on its label.
- It cannot tell you if a product is safe, legal, or real.
- It works only for U-100 insulin syringes. U-40 syringes are marked differently, and the result would be wrong.
- It never turns IU into mg or mcg. That depends on the substance, so only the label can tell you.
Common questions
- What is BAC water?
- BAC water is short for bacteriostatic water. It is sterile water with a small amount of benzyl alcohol added to slow the growth of germs. Its label says it is not for use in newborns.
- Why pick the units first?
- A whole number of units that is easy to read on your syringe can make each dose easier to measure. The calculator then works out how much water gives that.
- Does the amount of water change how much peptide I get?
- No. The water only spreads the same amount of peptide through more or less liquid. More water means you draw more units for the same dose.
- Can this calculator tell me what dose to use?
- No. It only does math with the numbers you type. Only a licensed clinician should set a dose.
Sources
The calculator uses one fixed fact: on a U-100 syringe, 100 units fill 1 mL. The rest is division with the numbers you type. It names no sellers and suggests no doses.
The needle, 28-day, and Poison Help lines come from the FDA, CDC, USP, and Poison Help pages listed here.
- 510(k) clearance K233794: Insulin Syringe (U-40 and U-100), March 6, 2024U.S. Food and Drug Administration · Checked
Quoted: “U-100 means there are 100 units of insulin in every mL”
- Bacteriostatic Water for Injection, USP (Hospira) labelDailyMed, U.S. National Library of Medicine · Checked
Quoted: “NOT FOR USE IN NEONATES”
- FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight LossU.S. Food and Drug Administration · Checked
Quoted: “Always use a new, sterile needle and syringe for each dose.”
- Preventing Unsafe Injection Practices, March 26, 2024Centers for Disease Control and Prevention · Checked
Quoted: “Never reuse a needle or syringe on more than one patient.”
Quoted: “Limit the use of multi-dose vials and dedicate them to a single patient whenever possible.”
Quoted: “the vial should be dated and discarded within 28 days unless the manufacturer states another date for that opened vial”
- USP General Chapter 797 FAQs, December 11, 2023United States Pharmacopeia · Checked
Quoted: “a conventionally manufactured multiple-dose vial may not be used after 28 days of first puncture”
- Calling Poison HelpHealth Resources and Services Administration · Checked
Quoted: “The toll-free Poison Help line is 1-800-222-1222.”
Quoted: “This number provides free and confidential help 24 hours a day, 7 days a week, 365 days a year.”