Peptide reconstitution calculator

The arithmetic, in one line

Dividing the vial’s peptide content by the water you added gives the concentration. Dividing your dose by that concentration gives the volume. A U-100 insulin syringe holds 100 units in 1 mL, so one unit is 0.01 mL — multiply the volume by 100 and you have the mark to draw to.

A 5 mg vial reconstituted with 2 mL of bacteriostatic water is 2.5 mg/mL, or 2,500 mcg/mL. A 300 mcg dose is 0.12 mL, which is the 12-unit mark. Add 4 mL of water to the same vial instead and that identical 300 mcg dose becomes 24 units. Nothing about the peptide changed — only the dilution did. This is why a unit count copied from someone else’s protocol is meaningless without their reconstitution.

Micrograms and milligrams

Peptides are prescribed in micrograms; the vial is labeled in milligrams. There are 1,000 micrograms in a milligram, so reading one as the other is a thousand-fold error in whichever direction you make it. If the dose you enter would be more than the entire vial holds, this calculator refuses to return a unit count rather than showing a drawable-looking number — that arithmetic impossibility is almost always a mcg/mg mix-up.

Why there is no suggested dose

Most peptides in this class have no FDA-approved dosing. Some have never been studied in humans at all, and the figures that circulate in forums are frequently extrapolated from animal work. Filling a default into the dose field would make this calculator into a dosing recommendation, which is not something we are in a position to give. The dose has to come from the clinician who prescribed it.

What each peptide actually is, what the evidence grade behind it looks like, and where it stands with the FDA is covered on the peptide reference pages — currently 12 of them, each with its regulatory status stated plainly.

Drawing accuracy

Insulin syringes lose precision at the bottom of their range. Below roughly a fifth of the barrel’s capacity the measurement error climbs steeply, so a dose that works out to two or three units is being measured on the least reliable part of the syringe. The fix is not a steadier hand — it is less bacteriostatic water, which concentrates the vial and moves the same dose up into a range you can actually read.