Frequently asked questions

Divide the peptide in the vial by the bacteriostatic water you added. A 5 mg vial reconstituted with 2 mL of water is 2.5 mg per mL, which is 2500 mcg per mL. Every other figure follows from that one: the draw volume for a dose is the dose divided by the concentration, and the units on the barrel are that volume multiplied by the units per mL of your syringe scale.

It depends entirely on the concentration of your vial, which is why no single answer exists. If a 10 mg vial was reconstituted with 2 mL of bacteriostatic water it holds 5 mg per mL, so 0.25 mg is 0.05 mL, which reads as 5 units on a U-100 barrel. Change the water volume and that unit count changes with it.

This site does not recommend a volume, because the right one depends on the product you have and its own labelling. Arithmetically the volume only decides how large the draw is: 1 mL makes a 5 mg vial twice as concentrated as 2 mL, so the same dose is half the volume and half the units, which is harder to measure accurately. Larger volumes give bigger, easier readings for the same dose.

The scale printed on the barrel. A U-100 syringe is graduated at 100 units per millilitre and a U-40 syringe at 40, so the same 0.1 mL reads as 10 units on one and 4 units on the other. Reading a U-40 barrel as if it were U-100 changes the amount drawn by two and a half times, which is why this calculator asks which one you have instead of assuming.

No. Every calculation runs in your own browser and nothing you enter is sent to a server. The inputs are mirrored in the address bar so a bookmark reopens the same calculation, which stays on your device; clear the query string and it is gone. See the privacy policy for what the hosting provider and analytics can see, which is ordinary request data and never a dose.

Because there is no approved product label to quote one from. This site publishes a dose schedule only when a regulator has approved the product and the schedule is printed on its label, as with semaglutide and tirzepatide. For compounds sold for research use there is no such document, and inventing a plausible looking range would be worse than leaving the space empty.

The reverse calculator takes syringe units and concentration (or vial amount plus diluent volume) and computes the peptide amount delivered. It multiplies the draw volume in mL by the concentration in mcg per mL to get the peptide amount in mcg, then converts to mg. The draw volume comes from dividing syringe units by units per mL of your syringe scale.

The BAC-water solver calculates the diluent volume needed to produce whole-number syringe units for a given dose. It divides the desired units times the vial mass by the dose mass times units per mL, producing a diluent volume that lands on clean syringe readings. This is pure arithmetic, not a medical recommendation.

A peptide calculator is arithmetic, not a medical device: it turns a vial mass, a diluent volume and a target dose into a concentration, a draw volume and a syringe reading. Given those three numbers it is exact, limited only by how precisely you measured the mass and the water; it cannot correct a mislabeled vial or a wrong assumption about purity. This peptide dosage calculator is free, runs in your browser, and works the same way whether you call it a peptide calc, a peptide dose calculator or a reconstitution calculator.

Concentration is mass divided by volume. Add a known volume of liquid to a vial of known mass and the two numbers give it directly: a 5 mg vial with 2 mL of diluent becomes 2.5 mg/mL. Nothing else is involved, which is why every other quantity on this site follows from that one division.

Multiply the draw volume in millilitres by the markings per millilitre on your syringe. A U-100 syringe has 100 markings per mL, so 0.1 mL reads as 10 units. A U-40 syringe has 40, so the same 0.1 mL reads as 4 units. The volume is identical either way; only the reading changes.

An international unit measures biological activity rather than mass, and the number of units per milligram belongs to a specific substance and often to a specific batch. The unit converters here ask you to supply the factor for the substance you actually have, because a factor borrowed from another one produces a confident, wrong answer.

Multiply by one thousand going from milligrams to micrograms, and divide by one thousand going the other way. One milligram is exactly one thousand micrograms. Both directions are separate calculators here, which is quicker than doing the arithmetic and quicker than risking the reversal.

Every later step divides by the concentration, so an error in it is inherited by everything downstream. Rounding 2.5 mg/mL to 3 mg/mL puts every draw volume and syringe unit twenty percent out, and the result still looks entirely reasonable. Keep full precision until the final display.

The arithmetic assumes nothing is lost, so real yields are always slightly lower. Filter retention, solution left on the vial wall, and dead volume in the syringe all account for material that the calculation treats as delivered. Small draw volumes make this proportionally worse, because the dead volume is a fixed amount.

A dose is a mass, such as 0.25 mg. A volume is how much solution contains it, such as 0.1 mL. One follows from the other through the concentration, and neither is the other: they are different kinds of quantity, and every calculator on this site makes you state which one you mean.

They hold the same volume. U-100 and U-40 describe the calibration, not the capacity: the U-100 is marked in hundredths of a millilitre and the U-40 in fortieths. The finer scale gives more numbers to read and a smaller step per marking, which is why the two are not interchangeable on the same reading.