Reconstitution and dose maths

Get the draw right every time.

Enter your vial size and how much bacteriostatic water you added. Drag the dose. The syringe fills as you drag, so you see the exact units to pull before you touch a needle.

The arithmetic, shown

5 mg in the vial ÷ 2 mL of water = 2.50 mg/mL
0.250 mg per dose ÷ 2.50 mg/mL = 0.100 mL
0.100 mL × 100 = 10 units on a U-100 syringe

BPC-157 · 5 mg vial U-100

Compound

Draw to 10 units

Volume 0.100 mL

Doses / vial 20

Dose per injection 250 mcg

Your vial

Vial size (mg)

Bacteriostatic water added (mL)

Resulting concentration 2.50 mg/mL

Check a report for this vial

What the calculator is doing

Milligrams in the vial, units on the barrel.

A 10 mg peptide vial plus 2 mL of bacteriostatic water gives a 5 mg/mL solution, and a 500 microgram dose is drawn to the 10 unit mark on a U-100 syringe. — A worked example, not your numbers: a 10 mg vial with 2 mL of bacteriostatic water gives 5 mg/mL. A 500 mcg dose is 0.1 mL of that solution, which is the 10 unit mark on a U-100 syringe. The dose is in micrograms and the draw is in units, and they are never the same number.

By compound

One page per compound, defaults set.

Each compound page opens on the vial sizes it actually circulates in, prints a table of common draws you can check by hand, and shows what the public Janoshik archive holds for that compound.

Tirzepatide calculator

Multi-dose vials against single-dose pens, and the overdraw mistake that follows.

Retatrutide calculator

The most tested compound in the public archive. Vials 5 to 30 mg, doses in whole milligrams.

Semaglutide calculator

The smallest doses of the GLP-1s: 0.25 to 2.4 mg, where a draw can shrink below readability.

BPC-157 calculator

Dosed in micrograms, which is exactly where the thousand-fold unit mistake lives.

GHK-Cu calculator

50 and 100 mg vials flip the usual problem: the risk is a draw too small to measure.

MOTS-c calculator

One vial size dominates the public record, and one public assay shows why labels are claims.

Legal status

Research use only

MechPeptides sells nothing. The compounds named in the calculator are there so the arithmetic has a label on it. None of them is approved by the FDA for human or veterinary use, none is a dietary supplement, and nothing on this site is medical advice or a recommended protocol.

The calculator performs arithmetic on numbers you enter. It converts a vial mass and a diluent volume into a concentration, then into a volume and a U-100 syringe reading. It does not know your compound, it does not recommend a dose, and its slider bounds are display ranges rather than guidance. Confirm every calculation independently before acting on it.