Master peptide reconstitution calculator
The most complete peptide dosing calculator on the web. Solve in any direction — for dose, syringe units, water volume, or doses-per-vial — across 40 peptide presets and every common insulin syringe. See the exact mark to draw to on a live syringe diagram, estimate cost-per-dose and how long a vial lasts, share your setup with a link, and print a dosing card. Educational math only, not medical advice.
Your vial
Match this to the syringe you actually own. U-100 is the common orange-cap insulin syringe (1 unit = 0.01 mL).
Result
Cost per dose
How long the vial lasts
Reading the result: the only number you read off the syringe barrel is units. Everything else is context. A draw under ~2 units is hard to measure precisely (add less water to concentrate); a draw over your barrel capacity won't fit (add more water or use a larger syringe).
How reconstitution math works
Reconstitution is dilution. The vial holds a fixed mass of peptide; the bacteriostatic water you add sets the volume; concentration is mass ÷ volume. From there every other number follows:
- Concentration = peptide mass ÷ water volume
- Draw volume = target dose ÷ concentration
- Units = draw volume × units-per-mL (100 for U-100, 40 for U-40)
- Doses per vial = total peptide ÷ dose per injection
Five-step reconstitution
- Read the mass printed on the vial (mg or mcg) and enter it above.
- Pick a water volume. Use Solve for water mode if you want the dose to land on a clean unit mark.
- Inject the water slowly down the inside wall of the vial — never spray directly onto the powder — and swirl, do not shake.
- Draw your dose to the unit mark the calculator gives you.
- Refrigerate the reconstituted vial and protect it from light.
Bacteriostatic vs. sterile water
Bacteriostatic water contains 0.9% benzyl alcohol that suppresses microbial growth, so a multi-use vial can be drawn from over days to weeks. Sterile water has no preservative and is for single use. Both set concentration identically — the difference is shelf life after the first draw, not the math.
Concentration cheat sheet.
Final concentration (and mcg per U-100 unit) for common vial-size and water-volume combinations. Tap a row to load it into the calculator.
Reconstitution FAQ.
How many units do I draw on an insulin syringe?
Divide your target dose by the concentration to get the volume in mL, then multiply by the syringe's units-per-mL (100 for a U-100 syringe). The "Solve for units" mode does this for you and highlights the exact mark on the syringe diagram.
How much bacteriostatic water should I add?
Any volume works mathematically — it only changes concentration. More water means more units to draw (easier to read small doses); less water means fewer units (higher precision risk). Use "Solve for water" to find the volume that makes your dose a clean, round number of units.
What's the difference between U-100, U-50 and U-40 syringes?
U-100 reads 100 units per mL (1 unit = 0.01 mL) and is the standard orange-cap insulin syringe. A "U-50" or "U-30" usually just means a smaller-barrel U-100 syringe (0.5 mL or 0.3 mL). A true U-40 syringe reads 40 units per mL (1 unit = 0.025 mL) — common in veterinary insulin. Always set the calculator to the syringe you actually hold.
Can I reconstitute peptides dosed in IU, like HCG?
Yes. Set both the vial and dose units to "IU" and the calculator works in International Units throughout — concentration becomes IU/mL and the per-unit figure becomes IU per syringe unit. Don't mix IU and mass units in the same calculation.
Why does my draw show more units than my syringe holds?
Your concentration is too dilute for that dose on that syringe. Either add less water (more concentrated, fewer units) or use a larger-capacity syringe. The calculator warns you when the draw exceeds the selected barrel.
Is this calculator medical advice?
No. It performs arithmetic only and does not know whether any dose is safe, sterile, legal, or appropriate for you. Many peptides in the directory are investigational, unapproved, or banned in sport. Dosing decisions belong to a qualified clinician. See the disclaimer.