Free Peptide Dosage Calculator Online – Exact BAC Water, Concentration & Insulin Syringe Units

Last updated August 2026 · Free · No signup required · Mobile-friendly for lab use

Avoid reconstitution mistakes. Enter vial size, bacteriostatic water volume, and target dose to get the exact syringe units to draw. This free peptide dosage calculator instantly converts your numbers into concentration (mg/mL & mcg/mL), draw volume, U-100 insulin units, and total doses per vial — the same math used by compounding pharmacies and research labs.

Reconstituting your vial – Step-by-step

Reconstitution is the process of adding liquid (almost always bacteriostatic water) to a freeze-dried (lyophilized) peptide so you can accurately measure and inject it. Follow these steps every time:

1. Clean both stoppers. Wipe the bacteriostatic water vial and the peptide vial with alcohol before puncturing either one.
2. Draw the water first. Pull the prescribed amount of bacteriostatic water into the syringe before adding anything to the peptide vial.
3. Add the water slowly. Aim the stream down the inside wall of the peptide vial instead of blasting the powder directly. This prevents foaming and peptide damage.
4. Swirl gently. Roll or swirl the vial until the powder dissolves completely. Do not shake it hard — mechanical stress can break peptide bonds.
5. Refrigerate after mixing. Keep the reconstituted vial cold (2–8 °C / 36–46 °F) and protected from light unless your supplier gives different storage instructions.

Get your target dose from a licensed provider — this calculator handles the arithmetic, not the protocol.

How the math works

Your peptide dissolves evenly in the water you add, so the concentration is simply the milligrams in the vial divided by the millilitres of water. Insulin syringes are marked in units, where 100 units equal 1 mL. The three formulas the calculator uses:

A 5 mg vial reconstituted with 2 mL of bacteriostatic water is 2.5 mg/mL, or 25 mcg per unit. A 250 mcg dose is therefore 10 units on a U-100 syringe — 0.10 mL. The vial holds 20 full doses.

If you only need to convert mcg ↔ mg, or a substance-specific IU value such as HGH/somatropin or HCG, use a dedicated peptide dose converter in addition to this tool.

Common reconstitution ratios

Starting points, not recommendations — set your own dose with a clinician. Select a row to load it into the calculator above.

Click any row to load those values into the calculator. Always verify the final numbers against your own vial label and protocol.

Insulin syringe size guide – Why barrel size matters

All standard insulin syringes use the U-100 scale (100 units = 1 mL). The difference between a 1 mL, 0.5 mL and 0.3 mL syringe is only the physical length of the barrel:

• 1 mL (100 unit) – most common. Good for doses of 10–80 units. Marks are farther apart than smaller syringes.
• 0.5 mL (50 unit) – ideal for medium doses. The same unit marks are spaced farther apart, making 5–40 unit draws easier to read accurately.
• 0.3 mL (30 unit) – best for very small doses (under 15–20 units). The finest resolution of the three.

The calculator always reports units on the U-100 scale. If you select a 0.5 mL or 0.3 mL syringe, the visual bar still shows the correct unit mark relative to a full 100-unit scale so you can cross-check.

How much bacteriostatic water should I add?

There is no single correct volume. Less water produces a higher concentration and smaller injection volume. More water produces a lower concentration and larger, easier-to-measure unit marks. Most researchers aim for a draw between 5 and 50 units on a U-100 syringe. Draws under 5 units become difficult to measure precisely; draws over ~60 units may require a larger syringe or splitting the dose.

Common mistakes that throw off peptide dosing

• Confusing mg and mcg (1 mg = 1000 mcg).
• Using sterile water for multi-dose vials (no preservative → higher contamination risk).
• Shaking the vial vigorously after adding water.
• Forgetting to account for the dead space in some syringe hubs.
• Storing reconstituted peptide at room temperature for extended periods.
• Mixing different peptides in the same syringe without checking compatibility.

Storage & stability after reconstitution

Once mixed with bacteriostatic water, most research peptides remain stable for 28–30 days when refrigerated at 2–8 °C and protected from light. Lyophilized (unreconstituted) powder is far more stable and can often be kept frozen for many months. Never freeze a reconstituted solution — ice crystals can damage the peptide structure. Discard any vial that becomes cloudy, discolored, or develops visible particles.

Frequently Asked Questions

Free peptide dosage calculator · No registration · Updated August 2026 · Designed for accuracy and clarity in research settings