Reconstitution calculator
Total mg printed on the vial
Bacteriostatic water you reconstitute with
Standard U-100 insulin syringe
Educational use only. This tool and content are for general information and do not constitute medical advice, diagnosis, or treatment. Peptides and GLP-1 medications should only be used under the supervision of a licensed healthcare provider. Always confirm dosing with your prescriber and the product label. Some peptides discussed are not approved by the FDA for human use.
Reconstitution, step by step
- Check the vial. Note the total milligrams of peptide printed on the label (e.g., 5 mg or 10 mg).
- Choose your BAC water volume. 1–3 mL is typical. More water = lower concentration = more units per dose (easier to measure small doses).
- Add the water slowly down the side of the vial; never spray it directly onto the powder. Swirl gently — do not shake.
- Calculate your draw. Enter the numbers above to see units on a U-100 syringe.
- Store it refrigerated and label the date. Most reconstituted peptides are used within a few weeks.
Why the BAC water amount matters
The same vial can read very differently on a syringe depending on how much water you use. A 5 mg vial in 1 mL is twice as concentrated as the same vial in 2 mL, so each dose is half the units. If your dose lands on an awkward number, change the water volume above until the units are easy to read.
Frequently asked questions
How much bacteriostatic water should I add?
There is no single “correct” amount — it sets the concentration. Many people use 1–2 mL so doses fall on clean syringe lines. Use the calculator to test a couple of volumes.
Can I use sterile or distilled water instead of BAC?
Bacteriostatic water is preferred for multi-dose vials because the benzyl alcohol limits bacterial growth. Sterile water has no preservative and is generally for single use. Follow your provider’s guidance.
How long does a reconstituted peptide last?
It varies by peptide and storage. Refrigerated and reconstituted with BAC water, many are used within ~4 weeks. Always check your specific product’s stability guidance.
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