Research Compound Dosing Math: A Step-by-Step Calculator Guide
The single most common mistake in research compound work isn’t reconstitution technique — it’s the dosing math. The conversion from milligrams of research compound, to millilitres of bacteriostatic water, to units on an insulin syringe trips up almost everyone the first time. This guide walks through the calculation step-by-step, with worked examples for the most common research compounds.
The three numbers you’re working with
- Vial size (mg). Printed on the label. Common sizes are 5 mg, 10 mg, 15 mg.
- Reconstitution volume (mL). How much bacteriostatic water you draw into the vial. You choose this. Most researchers use 1, 2, or 3 mL.
- Target research dose (mcg or mg). The amount of research compound you want per draw.
The core formula
Everything else flows from a single equation:
Concentration (mcg per mL) = (vial size in mg × 1000) ÷ reconstitution volume in mL
And on an insulin syringe (where 100 units = 1 mL):
Units to draw = (target dose in mcg ÷ concentration in mcg/mL) × 100
Worked example: BPC-157 5 mg vial
- Vial size: 5 mg = 5000 mcg
- Reconstitution volume: 2 mL of BAC water
- Concentration: 5000 ÷ 2 = 2500 mcg/mL
- Target research dose: 250 mcg
- Units to draw: (250 ÷ 2500) × 100 = 10 units on an insulin syringe
Worked example: TB-500 5 mg vial
- Vial size: 5 mg = 5000 mcg
- Reconstitution volume: 2 mL
- Concentration: 2500 mcg/mL
- Target research dose: 2 mg = 2000 mcg
- Units to draw: (2000 ÷ 2500) × 100 = 80 units
Worked example: Retatrutide 10 mg vial
- Vial size: 10 mg = 10,000 mcg
- Reconstitution volume: 2 mL
- Concentration: 5000 mcg/mL
- Target research dose: 2 mg = 2000 mcg
- Units to draw: (2000 ÷ 5000) × 100 = 40 units
Worked example: Tesamorelin 10 mg vial
- Vial size: 10 mg = 10,000 mcg
- Reconstitution volume: 2 mL
- Concentration: 5000 mcg/mL
- Target research dose: 1 mg = 1000 mcg
- Units to draw: (1000 ÷ 5000) × 100 = 20 units
Why reconstitution volume matters
Notice that the vial size and reconstitution volume together determine how many units one dose takes. If you reconstitute a 5 mg vial with 1 mL instead of 2 mL, every dose halves in volume — which means smaller draws and more sensitive measurement error. Pick a reconstitution volume that gives you draws between roughly 10 and 50 units. That keeps the math easy and the error small.
Insulin syringes: U-100 only
All the calculations above assume a U-100 insulin syringe, where 100 units = 1 mL. This is the standard syringe used in research compound work and the only one the math works for. Avoid U-40 syringes entirely — mixing them up is the most common cause of accidental under- or overdose.
Common dosing mistakes to avoid
- Confusing mg and mcg. 1 mg = 1000 mcg. A retatrutide “2 mg” dose is not the same as “2 mcg.”
- Confusing units and mL. Units are a syringe-specific measurement. 50 units on a U-100 syringe = 0.5 mL.
- Reconstituting with the wrong volume. Always log what you reconstituted with. Two researchers using identical vials can end up with completely different unit doses.
- Skipping the math entirely. Never copy unit doses from someone else — their vial size and reconstitution volume may not match yours.
A reusable mental shortcut
Once you have the concentration figured out, every dose conversion is a multiplication and a division. Write your vial’s concentration on a label or sticky note when you reconstitute it — then doses become a 5-second calculation rather than a head-scratch.
Pair this with the reconstitution guide
This post covers the math. For the physical technique — how to draw water, how to add it to the vial, how to avoid degrading the research compound — see the companion guide A Beginner’s Guide to Research Compound Reconstitution. And if you need supplies, you can add BAC water to your order with free express shipping Australia-wide.
Bottom line
The dosing math is unforgiving but small. Memorise the two formulas, label every vial with its concentration on the day of reconstitution, and stick to U-100 syringes. Once you’ve done it three times it becomes muscle memory — and you remove the single biggest source of error in research compound work.