Peptide Reconstitution & Dosage Calculator
Work out exactly how far to draw your syringe for a target dose. Enter your vial size, the bacteriostatic water you added, and your desired dose to get an instant, visual reading.
This calculator is a reference tool for laboratory research purposes only. It does not constitute dosing advice for human or animal use. Always follow your institution’s protocols and verify calculations independently.
What is a peptide reconstitution calculator?
Research peptides are typically supplied as a freeze-dried (lyophilized) powder sealed in a vial. Before that powder can be measured with a syringe, it has to be dissolved in a liquid, almost always bacteriostatic water, to create a solution with a known concentration. A reconstitution calculator takes three numbers you already know — how much peptide is in the vial, how much water you added, and the dose you want — and converts them into a single answer: how far to pull the syringe plunger.
It replaces manual arithmetic (and the rounding errors that come with it) with an instant, visual readout, so the same calculation can be repeated consistently across a research protocol.
How reconstitution math works
1. Find the concentration
Divide the total peptide mass in the vial (mg) by the volume of bacteriostatic water you added (mL). That gives you mg per mL.
2. Convert your dose
If your target dose is in mcg, divide by 1000 to get mg, so it’s in the same unit as your concentration.
3. Solve for volume
Divide your dose (mg) by the concentration (mg/mL) to get the volume to draw, then read that off your syringe’s unit markings.
Why accurate dosing matters
A small error in reconstitution math compounds every time the same vial is drawn from. Using too little water concentrates the solution, so the same syringe reading delivers more peptide than intended; using too much dilutes it below the target. Because a single vial is usually drawn from repeatedly across a protocol, an error in the initial calculation doesn’t just affect one draw, it affects every draw taken from that vial.
Working from a fixed concentration and a calculator rather than estimating by eye keeps every draw from the same vial consistent, which matters for reproducibility in any research setting.
Typical vial sizes by peptide
Vial sizes vary by supplier and product, but these are common amounts for widely studied research peptides. Always use the amount printed on your specific vial rather than assuming a standard size.
| Peptide | Common vial size |
|---|---|
| BPC-157 | 5 mg |
| TB-500 | 5 mg |
| Semaglutide | 5 mg |
| Tirzepatide | 5–10 mg |
| Retatrutide | 5–10 mg |
| CJC-1295 / Ipamorelin | 5 mg |
| NAD+ | 100 mg |
| Epitalon | 50 mg |
How to use this calculator
- Select your syringe size — 0.3 mL, 0.5 mL, or 1.0 mL, based on the U-100 insulin syringe you’re using.
- Enter the peptide amount printed on your vial, in milligrams.
- Enter the bacteriostatic water volume you used to reconstitute it, in milliliters.
- Enter your target dose and choose mcg or mg.
- Read the result — the syringe graphic and the text readout both update instantly to show exactly where to pull the plunger.
Standard U-100 insulin syringes are marked in “units,” where 100 units equals 1 mL. A 0.3 mL syringe is marked 0–30 units, a 0.5 mL syringe 0–50 units, and a 1.0 mL syringe 0–100 units — this calculator uses that same convention.
Frequently asked questions
What is bacteriostatic water and why does the amount matter?
Bacteriostatic water (BAC water) is sterile water containing 0.9% benzyl alcohol, used to reconstitute lyophilized peptides. The amount you add directly sets the concentration of your solution — more water means a more dilute solution and a larger draw volume for the same dose, less water means a more concentrated solution and a smaller draw volume.
Why does my calculated draw volume matter?
Research peptides are typically supplied as freeze-dried powder in a sealed vial. Reconstitution math converts the total mass in that vial into a concentration (mg/mL), so a specific dose can be measured out accurately with a syringe rather than estimated.
What if my calculated draw exceeds my syringe’s capacity?
If the draw volume is larger than your syringe can hold, either use a larger syringe, add less bacteriostatic water when reconstituting (to raise the concentration), or split the dose across two draws — this calculator will flag draws that exceed the selected syringe’s capacity.
Can I use this calculator for any peptide?
The math is the same regardless of which peptide is in the vial, since it’s based purely on mass, volume, and concentration. What differs between peptides is the typical vial size and the water volume used to reconstitute it, both of which you enter yourself.
Why do syringes use “units” instead of mL?
Standard insulin syringes are graduated in units (U-100 scale) rather than milliliters, because they were originally designed for insulin dosing. 100 units always equals 1 mL on a U-100 syringe, regardless of the syringe’s total barrel size, so this calculator converts your draw volume into units automatically.
How precise is the syringe reading in practice?
Insulin syringes are generally readable to the nearest 1–2 units by eye. If your calculated draw falls between marked graduations, round to the nearest visible line, or use a smaller syringe for finer resolution on small-volume draws.
Is this calculator a substitute for a lab protocol?
No. This tool is provided as a quick reference for research calculations only. Always follow your institution’s established protocols and independently verify any calculation before use in research.
Quick Conversion Key
Common mg ↔ mcg conversions and syringe unit references.
| Milligrams (mg) | Micrograms (mcg) |
|---|---|
| 0.1 mg | 100 mcg |
| 0.25 mg | 250 mcg |
| 0.5 mg | 500 mcg |
| 1 mg | 1,000 mcg |
| 2 mg | 2,000 mcg |
| 5 mg | 5,000 mcg |
| 10 mg | 10,000 mcg |
| Syringe size | Full scale |
|---|---|
| 0.3 mL (insulin) | 30 units |
| 0.5 mL (insulin) | 50 units |
| 1.0 mL (insulin) | 100 units |