Educational & research purposes only. These tools do not provide medical advice or dosing recommendations. Research peptides are not approved for human therapeutic use. Always consult a licensed healthcare provider.

Peptide Reconstitution, Explained

What reconstitution actually means, the simple arithmetic behind it, and the mistakes that matter. This page teaches the method — it is not a calculator for your personal protocol.

Educational / research calculation only — NOT medical advice. The numbers below are illustrative, chosen to demonstrate the arithmetic. They are not a recommended dose for any compound. Research peptides are not for human therapeutic use. Always consult a licensed healthcare provider, and follow their and your pharmacist's instructions.

The three steps

  1. Step 1 — Concentration

    concentration (mg/mL) = vial mg ÷ water mL

    How much peptide is in each millilitre once you add bacteriostatic water. More water → lower concentration → larger, easier-to-measure volumes (but the vial runs out sooner).

  2. Step 2 — Draw volume

    draw (mL) = portion mg ÷ concentration

    How many millilitres contain the portion you want. This is where the most dangerous error hides — see the units warning below.

  3. Step 3 — Syringe units

    units (U-100) = draw mL × 100

    On a U-100 insulin syringe, 100 units = 1 mL, so 0.1 mL = 10 units.

⚠️ The mg vs mcg trap (the costliest mistake)

1 mg = 1000 mcg. A 5 mg vial holds 5000 mcg. If a protocol is written in micrograms (e.g. “250 mcg”) and read as milligrams, that is a 1000× error. Always confirm which unit you are working in before doing any arithmetic — and verify with a licensed professional. Other things worth checking by hand: whether a draw volume is too small to measure accurately (a few units or less), larger than your syringe, or larger than the vial holds.

Worked examples

Illustrative numbers only — not dosing recommendations.

A standard mix

5 mg vial · 2 mL water · illustrative 0.25 mg portion

5 mg ÷ 2 mL = 2.5 mg/mL. Drawing an illustrative 0.25 mg portion: 0.25 ÷ 2.5 = 0.1 mL, which is 10 units on a U-100 insulin syringe (since 1 mL = 100 units).

A more concentrated mix (small, hard-to-measure volume)

10 mg vial · 1 mL water · illustrative 0.5 mg portion

10 mg ÷ 1 mL = 10 mg/mL. An illustrative 0.5 mg portion = 0.05 mL = 5 units. That is a very small volume — only a few units, which is hard to measure accurately by hand.

A more dilute mix (easier to measure)

5 mg vial · 3 mL water · illustrative 0.25 mg portion

5 mg ÷ 3 mL ≈ 1.67 mg/mL. The same illustrative 0.25 mg portion now = 0.15 mL = 15 units. More water makes the draw volume larger and easier to measure precisely — a trade-off against how long the vial lasts.

Concentration reference table

The concentration (mg/mL) you get from common vial sizes and water volumes. This is just vial ÷ water — a property of the mixed vial, not a dose.

Vial ↓ / Water →1 mL2 mL3 mL5 mL
2 mg2.00 mg/mL1.00 mg/mL0.67 mg/mL0.40 mg/mL
5 mg5.00 mg/mL2.50 mg/mL1.67 mg/mL1.00 mg/mL
10 mg10 mg/mL5.00 mg/mL3.33 mg/mL2.00 mg/mL
15 mg15 mg/mL7.50 mg/mL5.00 mg/mL3.00 mg/mL
30 mg30 mg/mL15 mg/mL10 mg/mL6.00 mg/mL

Stop doing this by hand

The Dosed app does the reconstitution math, saves it, and logs every dose and injection site — so you never re-derive it on a notepad. 100% on-device.

Get Dosed on iOS

Curious how long a compound stays active? Try the half-life visualizer.