# Reverse Reconstitution Calculator — units to dose | PepVault

Source: https://pepvault.app/tools/reverse-reconstitution-calculator

Last updated: 2026-09-29

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# Reverse reconstitution calculator

Already mixed your vial and drew some units? Work backwards — enter the vial, the water you added, and the units on the syringe to see exactly what dose that is.

Your vial and draw

Example numbers

That draw is 500 mcg, 0.5 mg. Concentration 2,500 mcg per mL, 10 doses per vial.

That draw is

500 mcg (0.5 mg)

0.3 mL insulin syringe · 30 units

- **Concentration:** 2,500 mcg/mL
- **Doses per vial:** 10

## Working reconstitution backwards

Reconstitution usually goes from dose to units: you know the dose you want and work out how many units to draw. The reverse is just as useful — you've already mixed a vial and want to know what a given draw *is*. The math runs the other way: **dose (mcg) = units ÷ 100 × concentration (mcg/mL)**, where **concentration = vial mg × 1000 ÷ water mL**.

Example: in a 5 mg vial mixed with 2 mL of water (2,500 mcg/mL), a 20-unit draw on a U-100 syringe is 500 mcg (0.5 mg), and the vial holds 10 doses.

Going the usual direction instead? Use the [reconstitution calculator](https://pepvault.app/tools/reconstitution-calculator) to turn a target dose into the units to draw, or mix the vial and draw it in the [3D Reconstitution Lab](https://pepvault.app/lab).

## Used most with

- [Semaglutide](https://pepvault.app/peptides/semaglutide)
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PepVault is a research and tracking resource, not medical advice. Ranges are what studies used, never a dose for you. Brand names are trademarks of their owners; PepVault is independent of them.

For educational and tracking purposes only — not medical advice. Always verify calculations and consult a qualified clinician before changing any protocol.

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