Reconstitution and dosing math in one place: how much bacteriostatic water to add, and where to draw on the syringe. Free, no signup.
For research reference only. The math assumes your vial contains what its label claims — check its published batch result first.
The calculator above converts vial size, water volume, and dose into exact syringe units for any peptide. Below: how the math works, which syringe to use, and the one assumption no calculator can check for you.
| Water added | Concentration | 1mg dose | 2mg dose | 5mg dose |
|---|---|---|---|---|
| 1 ml | 10 mg/ml | 10 units | 20 units | 50 units |
| 2 ml | 5 mg/ml | 20 units | 40 units | 100 units |
| 3 ml | 3.3 mg/ml | 30 units | 60 units | exceeds syringe |
Use a new sterile needle and syringe for every draw, wipe each vial stopper with an alcohol swab before puncturing it, and put used sharps straight into a sharps disposal container. Infection risk comes from handling, not from the arithmetic, so these steps matter as much as the numbers above.
The draw volume decides the syringe, and the calculator shows your draw volume instantly. Match it to the smallest syringe that fits:
| Syringe | Best for draws of | Notes |
|---|---|---|
| 0.3 ml U-100 insulin | under 0.25 ml | Finest graduations; the accuracy pick for small doses of potent compounds |
| 0.5 ml U-100 insulin | 0.25 to 0.45 ml | The workhorse for most reconstitution setups |
| 1 ml U-100 insulin | 0.45 to 1 ml | Needed when low concentrations push draws close to a full ml |
| 3 ml syringe | reconstitution only | Graduated in ml rather than units; right for adding bacteriostatic water to the vial, wrong for measuring doses under 0.5 ml |
The common mistake behind “peptide calculator for a 3ml syringe” searches: a 3ml barrel is a transfer tool. Use it to add water, then dose with an insulin syringe sized to your draw. If your calculated draw exceeds 1 ml, add less water next time to raise the concentration instead of reaching for a bigger barrel.
Dosing discussions mix three unit systems, and most dosing errors are unit errors:
This calculator assumes your 10mg vial holds 10mg. Published third-party testing shows label claims regularly miss in this market: failed results turn up regularly in Janoshik’s public results database. Check your vendor’s published batch results on their PeptideCensus profile before relying on the label.
There is no single right answer. More water means lower concentration and larger, easier-to-measure draws. 2ml on a 10mg vial (5 mg/ml) is a common middle ground in research protocols; small doses of potent compounds measure more accurately at lower concentrations.
Impossible to answer without concentration; that’s the point of the calculator. At 5 mg/ml, a 5mg dose is 1 ml = 100 units on a U-100; at 10 mg/ml it’s 0.5 ml = 50 units.
Yes: the reconstitution math is identical for retatrutide, tirzepatide, BPC-157, TB-500, or anything else in a lyophilized vial. Compound-specific context lives on each peptide hub.
The math still works in ml, but insulin syringes exist because sub-1ml volumes need fine graduations; a 3ml syringe measuring a 0.15ml draw is guesswork.
For reconstitution, yes: measure your bacteriostatic water with it. For dosing, convert to an insulin syringe; the calculator’s unit output is for insulin-syringe graduations (U-100 or U-40), and a 3ml barrel cannot resolve a 0.2 ml draw accurately.
With bacteriostatic water and refrigeration, research protocols commonly work within a several-week window, but stability varies by compound. Check the peptide’s hub page, and when in doubt, reconstitute smaller vials.
Yes, proportionally. A “10mg” vial that tested at 8mg makes every calculated dose 20% lighter than intended. That is why batch results matter more than arithmetic.