Underground Biohacking

Peptide dosing calculator

mg
mL

1 mg = 1000 mcg.

Your syringe
Draw this much

Enter a vial size, water volume and dose to see where to pull.

51015202530102030
0 units0.3 mL barrel, U-100 scale30 units

For tracking and calculation purposes only. Not medical advice. Based on a standard U-100 insulin syringe.

The numbers here describe your own vial. They are not medical advice and not a dose suggestion. Confirm your protocol with a qualified clinician.

How the units are worked out

Your vial holds a fixed amount of peptide. The water you add sets the concentration (how much peptide sits in each millilitre). The concentration then decides how much liquid carries your dose.

Three steps, in order:

  1. Concentration (mcg/mL) = peptide in the vial (mcg) divided by water added (mL).
  2. Volume (mL) = your dose (mcg) divided by the concentration (mcg/mL).
  3. Units to draw = volume (mL) multiplied by 100.

That last step is the syringe, not the peptide. A U-100 insulin syringe is marked so 100 units hold 1 mL, so 0.1 mL reads as 10 units.

A worked example

Enter your dose in the calculator above and this line shows the numbers worked through.

Water and units at a glance

your vial at different mixes. Every row opens the calculator on that mix.

VialWaterConcentration
10 mg1 mL10,000 mcg/mL
10 mg2 mL5,000 mcg/mL
10 mg3 mL3,333 mcg/mL
10 mg5 mL2,000 mcg/mL

Units appear once you enter a dose.

The pre-filled vial and water are an example: the most-used BPC-157 vial and water amounts in WPA dosing data (Aug 2026). There is no pre-filled dose. Not a recommendation.

Mixing and storage

Run the water down the inside wall of the vial and let the powder dissolve on its own. Never shake it. Label the vial with the compound, the total mass, the water you added, the concentration and the date. A sealed freeze-dried vial keeps 12 to 24 months in the fridge at 2 to 8°C. Once mixed with preserved water, such as bacteriostatic water, that drops to roughly 28 days refrigerated. Keep it at the back of the fridge, away from light and away from the door's temperature swings.

Other compounds

Questions

How do I work out the units to draw?
First work out the concentration. Divide the peptide in the vial (in micrograms) by the water you added (in millilitres). Then divide your dose by that concentration and multiply by 100. The answer is the units to draw on a U-100 insulin syringe.
Does the water I add change my dose?
No. The water changes the concentration, so it changes how much liquid carries the same dose. More water means a bigger, easier-to-read draw. Less water means a smaller draw of a stronger mix.
What does U-100 mean on a syringe?
U-100 means the barrel is marked so 100 units equal 1 millilitre. So 10 units are 0.1 mL, and 30 units are 0.3 mL. Almost every insulin syringe sold is U-100.
My draw is bigger than the syringe. What now?
You have two options. Use a bigger barrel, or mix the same vial with less water so the same dose sits in less liquid. The calculator flags the problem as soon as the draw passes what your syringe holds.
Why does the calculator use micrograms?
Vials are labelled in milligrams and most doses are talked about in micrograms, so mixing the two is the most common error we see. The calculator holds everything in micrograms and lets you switch the display. 1 mg is 1,000 mcg.
Where do the pre-filled numbers come from?
The pre-filled vial and water are an example: the most-used BPC-157 vial and water amounts in WPA dosing data (Aug 2026). There is no pre-filled dose. They are a starting point for the maths, not a recommendation. Type your own numbers over them.
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